What is a Chemical Engineer?

a) An Engineer who manufactures chemicals,

b) A Chemist who works in a factory, or

c) A glorified Plumber?

This is actually a trick question as the correct answer is d) "None of the above." (Note however that chemical engineering students bored with the relentless "pipe-flow example" during fluid dynamics class may begin to think of themselves as simply "glorified plumbers".)

The first two incorrect answers make sense based upon the narrow sounding title; "chemical engineer." Surely such a person must be either a "chemist who builds things", or an "engineer who makes chemicals". Yet, the English language has never really made any sense and the name "chemical engineer" is a case in point.

"Enough already...go to the bottom."

All Right, So What is a Chemical Engineer?

It is true that chemical engineers are comfortable with chemistry, but they do much more with this knowledge than just make chemicals. In fact, the term "chemical engineer" is not even intended to describe the type of work a chemical engineer performs. Instead it is meant to reveal what makes the field different from the other branches of engineering.

All engineers employ mathematics, physics, and the engineering art to overcome technical problems in a safe and economical fashion. Yet, it is the chemical engineer alone that draws upon the vast and powerful science of chemistry to solve a wide range of problems. The strong technical and social ties that bind chemistry and chemical engineering are unique in the fields of science and technology. This marriage between chemists and chemical engineers has been beneficial to both sides and has rightfully brought the envy of the other engineering fields.

The breadth of scientific and technical knowledge inherent in the profession has caused some to describe the chemical engineer as the "universal engineer." Yes, you are hearing me correctly; despite a title that suggests a profession composed of narrow specialists, chemical engineers are actually extremely versatile and able to handle a wide range of technical problems.

So What Exactly Does This "Universal Engineer" Do?

During the past Century, chemical engineers have made tremendous contributions to our standard of living. To celebrate these accomplishments, the American Institute of Chemical Engineers (AIChE) has compiled a list of the "10 Greatest Achievements of Chemical Engineering." These triumphs are summarized below:

The Atom, as Large as Life:

Biology, medicine, metallurgy, and power generation have all been revolutionized by our ability to split the atom and isolate isotopes. Chemical engineers played a prominent role in achieving both of these results. Early on facilities such as DuPont's Hanford Chemical Plant used these techniques to bring an abrupt conclusion to World War II with the production of the atomic bomb. Today these technologies have found uses in more peaceful applications. Medical doctors now use isotopes to monitor bodily functions; quickly identifying clogged arteries and veins. Similarly biologists gain invaluable insight into the basic mechanisms of life, and archaeologists can accurately date their historical findings.

The Plastic Age:

The 19th Century saw enormous advances in polymer chemistry. However, it required the insights of chemical engineers during the 20th Century to make mass produced polymers a viable economic reality. When a plastic called Bakelite was introduced in 1908 it sparked the dawn of the "Plastic Age" and quickly found uses in electric insulation, plugs & sockets, clock bases, iron cooking handles, and fashionable jewelry (see OIL). Today plastic has become so common that we hardly notice it exists. Yet nearly all aspects of modern life are positively and profoundly impacted by plastic.

The Human Reactor:

Chemical engineers have long studied complex chemical processes by breaking them up into smaller "unit operations." Such operations might consist of heat exchangers, filters, chemical reactors and the like. Fortunately this concept has also been applied to the human body. The results of such analysis have helped improve clinical care, suggested improvements in diagnostic and therapeutic devices, and led to mechanical wonders such as artificial organs. Medical doctors and chemical engineers continue to work hand in hand to help us live longer fuller lives.

Wonder Drugs for the Masses:

Chemical engineers have been able to take small amounts of antibiotics developed by people such as Sir Arthur Fleming (who discovered penicillin in 1929) and increase their yields several thousand times through mutation and special brewing techniques. Today's low price, high volume, drugs owe their existence to the work of chemical engineers. This ability to bring once scarce materials to all members of society through industrial creativity is a defining characteristic of chemical engineering (see Plastics above, Synthetic Fibers, Food, and Synthetic Rubber below).

Synthetic Fibers, a Sheep's Best Friend:

From blankets and clothes to beds and pillows, synthetic fibers keep us warm, comfortable, and provide a good night's rest. Synthetic fibers also help reduce the strain on natural sources of cotton and wool, and can be tailored to specific applications. For example; nylon stockings make legs look young and attractive while bullet proof vests keep people out of harm's way.

Liquefied Air, Yes it's Cool:

When air is cooled to very low temperatures (about 320 deg F below zero) it condenses into a liquid. Chemical engineers can then separate out the different components. The purified nitrogen can be used to recover petroleum, freeze food, produce semiconductors, or prevent unwanted reactions while oxygen is used to make steel, smelt copper, weld metals together, and support the lives of patients in hospitals.

The Environment, We All Have to Live Here:

Chemical engineers provide economical answers to clean up yesterday's waste and prevent tomorrow's pollution. Catalytic converters, reformulated gasoline, and smoke stack scrubbers all help keep the world clean. Additionally, chemical engineers help reduce the strain on natural materials through synthetic replacements, more efficient processing, and new recycling technologies.

Food, "It's What's For Dinner":

Plants need large amounts of nitrogen, potassium, and phosphorus to grow in abundance. Chemical fertilizers can help provide these nutrients to crops, which in turn provide us with a bountiful and balanced diet. Fertilizers are especially important in certain regions of Asia and Africa where food can sometimes be scarce (See NITROGEN). Advances in biotechnology also offer the potential to further increase worldwide food production. Finally, chemical engineers are at the forefront of food processing where they help create better tasting and most nutritious foods.

Petrochemicals, "Black Gold, Texas Tea":

Chemical engineers have helped develop processes like catalytic cracking to break down the complex organic molecules found in crude oil into much simpler species. These building blocks are then separated and recombined to form many useful products including: gasoline, lubricating oils, plastics, synthetic rubber, and synthetic fibers. Petroleum processing is therefore recognized as an enabling technology, without which, much of modern life would cease to function (see OIL).

Running on Synthetic Rubber:

Chemical engineers played a prominent role in developing today's synthetic rubber industry. During World War II, synthetic rubber capacity suddenly became of paramount importance. This was because modern society runs on rubber. Tires, gaskets, hoses, and conveyor belts (not to mention running shoes) are all made of rubber. Whether you drive, bike, roller-blade, or run; odds are you are running on rubber.

Chemical Engineering Today & Tomorrow

The "Big Four" engineering fields consist of civil, mechanical, electrical, and chemical engineers. Of these, chemical engineers are numerically the smallest group. However, this relatively small group holds a very prominent position in many industries, and chemical engineers are, on average, the highest paid of the "Big Four" (see WAGES). Additionally, many chemical engineers have found their way into upper management. A chemical engineer is either currently, or has previously, occupied the CEO position for: 3M, Du Pont, General Electric, Union Carbide, Dow Chemical, Exxon, BASF, Gulf Oil, Texaco, and B.F. Goodrich. Even a former director of the CIA, John M. Deutch, was a chemical engineer by training.

More typically, chemical engineers concern themselves with the chemical processes that turn raw materials into valuable products. The necessary skills encompass all aspects of design, testing, scale-up, operation, control, and optimization, and require a detailed understanding of the various "unit operations", such as distillation, mixing, and biological processes, which make these conversions possible. Chemical engineering science utilizes mass, momentum, and energy transfer along with thermodynamics and chemical kinetics to analyze and improve on these "unit operations."

Today there are around 70,000 practicing chemical engineers in the United States (57,000 of these are AIChE members) (see AIChE MEMBERSHIP). During the entire history of the profession there have been only about 135,000 American chemical engineers (including those alive today). This means that more than a half of all the chemical engineers who have ever existed are contributing to society right now! Chemical engineering is not a profession that has to dwell on the achievements of the past for comfort, for its greatest accomplishments are yet to come.

What Is Stainless Steel and Why Is it Stainless?

In 1913, English metallurgist Harry Brearly, working on a project to improve rifle barrels, accidentally discovered that adding chromium to low carbon steel gives it stain resistance. In addition to iron, carbon, and chromium, modern stainless steel may also contain other elements, such as nickel, niobium, molybdenum, and titanium. Nickel, molybdenum, niobium, and chromium enhance the corrosion resistance of stainless steel. It is the addition of a minimum of 12% chromium to the steel that makes it resist rust, or stain 'less' than other types of steel. The chromium in the steel combines with oxygen in the atmosphere to form a thin, invisible layer of chrome-containing oxide, called the passive film. The sizes of chromium atoms and their oxides are similar, so they pack neatly together on the surface of the metal, forming a stable layer only a few atoms thick. If the metal is cut or scratched and the passive film is disrupted, more oxide will quickly form and recover the exposed surface, protecting it from oxidative corrosion. (Iron, on the other hand, rusts quickly because atomic iron is much smaller than its oxide, so the oxide forms a loose rather than tightly-packed layer and flakes away.) The passive film requires oxygen to self-repair, so stainless steels have poor corrosion resistance in low-oxygen and poor circulation environments. In seawater, chlorides from the salt will attack and destroy the passive film more quickly than it can be repaired in a low oxygen environment.

Types of Stainless Steel

The three main types of stainless steels are austenitic, ferritic, and martensitic. These three types of steels are identified by their microstructure or predominant crystal phase.

Austenitic:
Austenitic steels have austenite as their primary phase (face centered cubic crystal). These are alloys containing chromium and nickel (sometimes manganese and nitrogen), structured around the Type 302 composition of iron, 18% chromium, and 8% nickel. Austenitic steels are not hardenable by heat treatment. The most familiar stainless steel is probably Type 304, sometimes called T304 or simply 304. Type 304 surgical stainless steel is an austenitic steel containing 18-20% chromium and 8-10% nickel.

Ferritic:
Ferritic steels have ferrite (body centered cubic crystal) as their main phase. These steels contain iron and chromium, based on the Type 430 composition of 17% chromium. Ferritic steel is less ductile than austenitic steel and is not hardenable by heat treatment.

Martensitic:
The characteristic orthorhombic martensite microstructure was first observed by German microscopist Adolf Martens around 1890. Martensitic steels are low carbon steels built around the Type 410 composition of iron, 12% chromium, and 0.12% carbon. They may be tempered and hardened. Martensite gives steel great hardness, but it also reduces its toughness and makes it brittle, so few steels are fully hardened.

There are also other grades of stainless steels, such as precipitation-hardened, duplex, and cast stainless steels. Stainless steel can be produced in a variety of finishes and textures and can be tinted over a broad spectrum of colors.

Passivation

There is some dispute over whether the corrosion resistance of stainless steel can be enhanced by the process of passivation. Essentially, passivation is the removal of free iron from the surface of the steel. This is performed by immersing the steel in an oxidant, such as nitric acid or citric acid solution. Since the top layer of iron is removed, passivation diminishes surface discoloration. While passivation does not affect the thickness or effectiveness of the passive layer, it is useful in producing a clean surface for a further treatment, such as plating or painting. On the other hand, if the oxidant is incompletely removed from the steel, as sometimes happens in pieces with tight joints or corners, then crevice corrosion may result. Most research indicates that diminishing surface particle corrosion does not reduce susceptibility to pitting corrosion.

1001 things to do with Liquid Nitrogen

In the course of studying physics one is officially taught that liquid nitrogen is simply (and mainly) used to cool things down to 77K. But everybody who once has observed students in practical courses "working" with this stuff knows that this is not true.
My intention is now to tell the truth about what is really done with liquid N2 before its remains are taken and used for cooling.


As we all know liquid nitrogen is mainly used for...

# making icecream by stirring for example yoghurt under it.
(mind the carpet!; Darmstadt Group)


# Roger Carlson comments on this topic

I have pix of making ice cream (with a good recipe), feel free to link
to them if you want:

http://www.rogerandjudycarlson.com/roger/icecream/pix_ice_cream.html


# putting pieces of chalk in it for making little hovercrafts (best on linoleum floors!)


# twirling in large basins so that because of its low viscosity you get a
(nearly) infinitly turning maelstrom. It's good fun to watch little
paper-boats floating on it for minutes.


# inhaling its fumes because everybody will make eyes on you exhaling.


# freezing your partner's chair while he is shortly absent.


# for squirting water in it. If you use a spray-bottle you can squirt funny
ice patterns into a basin with nitrogen. My alltime favorite: Helmar's ice-earrings


# one word: marshmellows


# its nice for cooling a good beer in a basin of water on which the nitrogen is poured
(not much fun to look at, but great fun to drink; Darmstadt Group)


# Put on a rubber surgical glove with a hot dog (saussage) stuck in one of the
fingers. Put the hot dog in the liquid nitrogen and then, to the amazement
of your friends, smash your "finger" with a hammer. (Wes Denisson)
Comment: Keep in mind which finger...


# Get a pot of boiling water and pour some nitrogen in it. You will watch the
mists of hell shrouding the floor. It's good fun to test how long
you can stand sticking a finger into it - a cool feeling ...


# Get about a liter of soap bubble solution hot and pour about a cupful of liquid
nitrogen in it. Bubbles go everywhere! (Wes Denisson)


# Break a light bulb, put the filament into liquid nitrogen and turn it on.
Looks cool! (Wes Denisson)


# Put a little bit of nitrogen in a can with a plastic snap on lid. We use a
Pringles Chip can. After you pour in the nitrogen seal the lid. The lid will
pop off with a boom and fly off. (David Hutchison)


# Blow up a balloon. Put the inflated balloon in the nitrogen. It will deflate,
then take it out and it will inflate as it warms up. (David Hutchison)


# A siberian frog frozen in liquid nitrogen shall come to life again if you throw
it back into the water. (Prof. Alois Loidl, who never tried it in public, but
used a wind-up frog of his children instead, for demonstration)


# Freeze a can of shaving cream and then peel the can away from the
cream. Put the canless cream into someone's car. Let the oven-like
heat from the car's sitting in the sun defrost the shaving cream.
2 cans will fill an entire car. (Coulter C. Henry, Jr.)


# Freeze a banana in liquid nitrogen and use it to hammer a nail. (Wes Dennison)


# Here is a small anecdote from Markus Selve (Stuttgart, Germany) I will just quote:

"Wir haben hier nebenbei auch 'ne Anwendung entdeckt.
Eigentlich wollten wir eine wassergefüllte PET-Flasche (Cola)
unter Druck setzen und dann als Rakete hochschießen. Mit Aufpumpen haben wir leider
nur 5 bar erreicht. Deswegen haben wir in die Colaflasche ca. halb mit Wasser gefüllt.
und dann ca 100 - 200 ml LN2 zugegeben und den Deckel geschlossen. Im Deckel war ein
Loch in das wir ein Fahrradventil (nur die äussere Röhre ohne den eigentlichen
Ventileinsatz) gesteckt hatten. Da drin war ein Gummistöpsel. Eigentlich sollte es bei
Erreichen des Enddrucks (was auch immer der hätte sein sollen) den Stopfen rausdrücken
und die Rakete vom Wasserstrahl hochgehoben werden. Es hat aber den gesamten Schraubdeckel
abgerissen. Das Wasser ging ziemlich schnell raus und die Rakete ist immerhin bis zum 7.
Stock (ca. 30m) geflogen."


# Here is another quote from Jeeplass (Philadelphia):

As an employee of the Franklin Institute Science Museum in
Philadelphia, Pennsylvania, I had many occasions to use liquid nitrogen in our Hot & Cold show:
One thing we used to do for smaller groups was to freeze a graham cracker and
then eat it. The vapors released through your mouth and nose are quite
dramatic and it really does tintilate your tastebuds! Of course, we usually
waved the cracker around just a little before eating it to be sure no drops of
the really cold stuff linger.


# This story was mailed to me by Earl Blodgett (Wisconsin)

For several years our Society of Physics Students
chapter has entertained visiting students with a spectacular liquid nitrogen depth charge.
The term "depth charge" is used because we have a large extremely durable plastic trash can filled
with about 40 cm of water. - After a short safty talk, focusing on the rule of NEVER tightly sealing
a vessel containing liquid nitrogen, we use a long-necked metal funnel to pour perhaps half a liter of
liquid nitrogen into an ordinary 2 liter soda bottle. Then we tightly screw on the cap, and drop it into
the water! - For several seconds, one can hear the bottle expanding! The preferential orientation of the
polymers makes the bottle get longer and longer, rather than a more spherical expansion. However, eventually
the polymers just can't take it anymore, and BOOM! A quite satisfying detonation, sending water, nitrogen
vapor, and bits of plastic high into the air. - The heavy duty plastic can serves to direct the "shrapnel"
upwards, it is lots safer this way versus just setting the bottle on the grass and running away!
(picture 1, picture 2)


# Larry Weinstein sent me the following: We have two more demos we use LN2 for here at ODU:

1) Take a 'ringshooter' (used to demonstrate Lenz's Law by placing an aluminum ring around
an AC electromagnet [made by wrapping wire around a long thin iron core - typically 15-20 cm
high and 3 cm in diameter] - the Al ring will jump into the air, a split Al ring and a nonconducting
ring will not move) and demonstrate that the Al ring will jump from the magnetic repulsion. Now
chill the Al ring in LN2. Repeat the demonstration and the ring will jump MUCH higher (since its
resistance decreases substantially at -200 C)

2) Take a thinwalled metal cone, point downward (a sealed metal funnel will work). Fill it with LN2.
Wait. Oxygen will condense out of the air and drip from the tip of the cone. Hold the tip of the funnel
between the poles of a strong magnet. The drops of liquid oxygen will levitate there (if the field is
strong enough) giving a rare good demonstration of paramagnetism. (This demo is courtesy of Sebastian
Kuhn, also at ODU.)

# Four suggestions by TOM MILLER (Air Force Research Lab):

(1) Start a show by sticking one end of very flexible tubing
(e.g., latex or tygon) down into a dewar; the heat of the tubing
will cause LN2 to spray out the other end of the tubing, and
you can direct the spray at the audience. After the submerged
end of the tubing is completely frozen (and the spraying stops),
remove from the dewar and whack the frozen end on a table
and watch it break into pieces.

(2) Wrap a long piece of latex tubing around itself and stick
the whole thing into a dewar of LN2 until completely frozen.
Remove and place on a table, and continue with the rest of
your show. After a few minutes, the tubing will slowly start to
move, sometimes crawling across the table.

(3) Stick flowers in LN2 and then crumble them in my hand;
large ones like carnations are best. Sounds simple, but the
kids love it.

(4) I freeze balloons, as you mention, but in a better way.
Blow up a balloon and slip the end of the balloon over the open
end of a test tube, and place the closed end in a dewar full of
LN2. Your breath in the balloon will slowly liquify (10-15 minutes).
When the balloon is completely deflated, lift the test tube out of
the dewar and the audience can see your liquified breath in the
test tube. The tube will frost up, but you can wipe the frost off
with your fingers. Rest the test tube in a beaker, and as time
passes, the balloon will inflate again.


# Bob sent me an email reading:

not exactly a *fancy* idea, but I thought it was cool;
bouce (or have a volunteer bounce) a soft, hollow ball. then freeze the ball LN2 style.
using gloves, try to bounce the ball again. The always neat shattering effect will be
accompanied by a loud bang.

also, throwing LN2 from a bucket at a wall - preferably above someone -
creates some interesting effects (the wall will "smoke" for a while)


# An email with the following idea comes from Ken Hubbard (da Vinci Middle School, Eugene, Oregon):

I do another "trick" with my middle school students. If you put about 10 ml of LN2 into
a styrofoam cup into a bell vacuum you can see solid nitrogen. The crystalization "puffs" up
very quickly. Really cool to be able to see N as a solid, liquid and a gas.


# Something nasty is proposed by Craig Shaw:

fill a small bottle with ln2 then screw the lid on tight. Put in a bag of flour and seal with elastic band. Then run


# Åge Guddingsmo from Norway suggested the following:

The other day me and some other students where playing around with Liquid Nitrogen.
I got the Idea to put it in 1/2 l soda bottle and watch it blow. To increase the rate
of heat into the bottle we used water. We used a 10 l bucket with water. It resulted in
an huge explosion, leaving the bucket in small pices over a larger area.


# Something for the techies among the readers of this site sent to me by Ralph Lewis Newman-Allen

ya this isnt as quick or as easy to do as most of the fun things on the site..
but a project that someone else accomplished in finaldn i think (not sure where) use a
liquid nitrogen bath to cool a AMD 1ghz cpu and overclocked it to 2ghz.
The guy mentioned, and this is what im hopefully going to accomplish/find out,
that he probobly could have overclocked it further then that but he apparently didnt have
a large enough powersupply.

This is the thing thats curious though. Im no expert in computers just a long
term intermediate user, butas far as i know most of the power goes to your monitor
(about 80% less with an LCD monitor) but even then its still probobly the most.
I wonder how minimal the cpu power drain really is on the system overall and how cost
effective it would be in the long term to just pay a few extra bucks a month, if
thats what it would amount to, for electricity then to buy a new pc system every year.

Of course theres always the cost of the nitrogen compressor too which would prob be a tad expensive.


# Ron George from Llanelli, Wales (UK) wrote to me:

I "fry" an egg using LN2. Crack an egg into a frying pan. Pour LN2 over the egg.
It turns into a "fried egg"! When it warms up again, it becomes an uncooked egg once more.


# Paul Beauregard is writing:

Pour LN2 on the tile floor with a sweeping action as you walk. It gathers
up dust into a gray mat like felt. It's sort of like using a water hose on
a driveway to push dirt in one direction. Great for 'dusting' under heavy
machinery or instruments. Sweep up the gathered dust at the edges of the
room or the low point in the room and it's gone.


# Tish Richey gives an example pour les Chefs

One of my favorite liquid nitrogen demonstrations is to place an egg (raw & in shell)
in container and cover with liquid nitrogen. after the nitrogen has evaporated,
take the egg out smash it with a hammer, it appears to be hard boiled.
As it cools it returns to white and yolk.


# Lets hope the fire brigade takes this joke (Dr Lucio Baggio; Univ. of Trento, Italy)

Hide a Dewar into one friend's dorm, drop LN2 around when he is not watching, and
then cry "FIRE". This was told me by a friend of mine, who enjoyed to see the attempts
of the victim to stop the fire...


# Richard Mack tells us about effectively cleaning floors:

LN2 also works great for sweeping and cleaning hard floors such as concrete or wood.
Get a couple liters in a container, and dump it on the floor in the direction
you want the debris to travel. It picks up everything in it's wave and if it hits a wall,
the wave will boil off and deposit the junk there. Now all you have to do is go
around the perimeter and sweep up the clutter.


# James McSheehy agrees with Richard Mack

LN2 is great for cleaning linoleum or vinyl floors. As it rolls across
the floor and boils, it picks up dirt, dust, and small debris. With a
little practice, the detritus can be sent in a specific direction and
deposited under a lab bench or out the door. Perfect for fast clean-ups
when lab directors decide to visit the worker bees.


# Jeremy A. Smith tells us a small story:

At the Gettysburg College Physics department we used to do all kinds of liquid
nitrogen demos to wow visting students. All pretty run of the mill stuff, but
at the end of the spring semester the department head would give the Society
of Physics Students free reign to play with the remaining liquid, as most of
it would dissipate over the summer break anyway.

We did several 'depth charge' style explosions in the fountain that sat in
front of the physics building. Unsatisfied with that we created a liquid
nitrogen cannon with a simple piece of thick cylindrical pipe, capped off
and weighted at one end (we also had free reign of the physics department
metal shop). We would put a small amout of liquid nitrogen in a 16 ounce
plastic bottle, tighten the lid as taight as possible, and placed it upside
down in the cannon. Then we placed a lacrosse ball on top of the bottle...
if you ever noticed, those bottles are concave on the bottem and thus made
perfect resting points for spherical projectiles. We would expediate the
expansion of the gas by pouring some water into the cannon. The explosion
would be very impressive, launching the ball tremendous distances. With a
stop watch and some quick application of basic kinematics we determined we
could get the ball to reach heights of over 40 meters! An impressive show
to say the least. We were never able to find a suitably sized pipe to
create a 2-liter bottle cannon... probably for the better, as we probably
would have tried launching bowling balls or something.

As a side note, we only ever had one mishap. Once we fumbled a bit too long
with the cannon and a bottle exploded in my hand. The most significant
damage was the startle. The concussion was considerable though, numbing my
hand for twenty minutes or so. The only other lasting repercussion was some
scratches from the tattered plastic shards. Lesson to be learned: Physics
fun is not without its hazards.


# Another story by Chad Orzel (Physics Department, Union College)

Regarding the "Liquid nitrogen in a Coke bottle" trick,
you really ought to warn your readers to be cautious about
trying that one. I know of a case at MIT where a bored
graduate student put liquid nitrogen in a Coke bottle, and
became alarmed when the bottle started to swell up. He
couldn't get the cap off, so he put the bottle in a restroom
sink, and waited outside the door.

The resulting explosion destroyed the sink, and drove little
slivers of plastic into the walls and ceiling. I've seen
pictures of the aftermath-- the damage was pretty impressive.
Somebody in the same room when the bottle blew could've been
seriously injured.

(Of course, since nobody _was_ injured, it's a funny story.
I'm especially fond of the coda, where the campus police
called his advisor at home (the whole thing happened in the
early morning hours), and told him that one of his students
had blown up the lab with nitroglycerin... The advisorm
needless to say, was rather relieved to learn that said student
had only destroyed a bathroom with liquid nitrogen.)


# no comment on the following suggestion by Edward Lin (California)

Another trick you can do is to "drink" LN2. since the nitrogen will vaporize
when it gets near your tongue, it will float on an insulating bed of
nitrogen gas and not actually freeze your tongue. You can then blow smoke
and impress your friends. Important Note: dont drink very much at a time
(just a sip) otherwise your skin temperature may eventually get to freezing,
and also do not actually swallow since your epiglotis will seal off your
esophagus and hold the LN2 long enough to freeze the surrounding tissue.


# Marshall Hampton has tried the same as above

You can put a little in your mouth (not too much!! - about half a small
spoonful) and let wisps of vapor come out. This is quite safe if you don't
overdo it - like water on a very hot stove, the N2 doesn't wet the surface.


# Here is what Ian Hook (Ex. University of New England) mailed to me:

Warning ?
My clumsy physics Lab partner was always knocking over or spilling things.
So naturally when a beaker was spilt all over my Lab note book, I grabbed it
and lifted quickly out of the way.
How does one explain to the lecturer why my entire years work is shattered into
a hundred pieces ?

Luckily the partner did not stay for another year. He noted that a 1 inch diameter
polished steel optical reflector was very dirty. It needed more than just a simple wipe.
Intending to moisten it........ he lost a huge chunk out of the centre of his tongue !
I think he was expelled after a "snap oral test".

Otherwise, it's great fun for the careful.


# Another nice trick was mailed to me by Dan Dulek (Stagg High School)

Try taking a ping-pong ball and poking a small hole in it. The hole has to be tangent
to the sphere of the ball. When poking the hole use a pin and the pin should be almost
flat agianst the ball. Basiclly you want a hole in the side of the ball that will cause
the ball to spin. Submerge this ball into the liquid nitrogen and let it fill up.
Place the ball on a table and watch it spin. As the nitrogen goes back to a gas it will
rush out the hole and presto!! It's pretty cool. If it does not spin try placing your
hand on it to warm it to get it started.


# Michael L. Clark, PE mailed to me the following text:

One of my favorite demonstrations is to freeze miniature marshmallows and
allow the participants to eat them. The thermal mass is quite low, thus
there is little danger of injury, but if eaten quickly, they still create a
small cloud of vapor.

The marshmallows are not as messy as other frozen foods. Frozen Tootsie
Rolls are also very good.


# Then I got the following message by Airframe123_at_aol.com:

Hey, i think you have great ideas[;] here are some of mine (Tested safe)
* You can put you[r] hand in liquid nitrogen and pull it out quickly (Bare hands)
* Pour a tbsp of liquid nitrogen into your hands quickly switch hands.

Safer projects

* Put a helium filled ballon in the liquid nitrogen take it out after 15-25
seconds. Drop it, it will fall to the ground and the float once more
* Put a leaf in liquid nitrogen, shatter it with your hands (Wear gloves)
* Put a rubber band in the liquid nitrogen, try to stretch it (Breaks doesn't it)
* Put 10 ballons in the liquid nitrogen (2quarts or more container) It will
amaze your friends (Wow all those fit?) Take it out and watch it inflat.


# John H. DuBois III sent me the following:

We initially acquired LN2 to make ice cream (which I've found to be especially
enjoyable in the heat of the desert, at Burning Man). But this inevitably led
to further experimentation. Some of the things we've done with it:

I dipped a large butane cylinder (the type used to refill torches and lighters)
into LN2 long enough for it to solidify, then removed it, cut it open, and
pulled out the large waxy ingot of butane. I chipped pieces off and set them
in the patio and lit them; they slide downhill as the butane on the bottom
re-liquifies, with the flames getting larger and larger. I finally took the
whole remaining piece and did the same with it, keeping an eye on it to make
sure it didn't catch anything on fire.

For a "Mad Science" party, I tried making butane ice cubes for drinks. I made
a small pressure vessel out of pipe pieces and connected it via tube to a
cylinder of butane. I dipped the vessel in LN2, and after waiting for it to
cool down, injected butane into it and let it solidify. Then I removed the
vessel from the LN2 and opened it up and removed the plug of butane. I ended
up only making one, but I was able to drop it in a flask of water and ignite
the butane gas the poured out. I ended up winning the party's top prize (a
radiometer) for this experiment. I think that may have had something to do
with the liquid butane that dripped off of the plug onto my pants and caused
them to burst into flame when I lit the flask.

My housemate showed me that he could pour LN2 into a metal measuring cup, and
tilt it a bit so that the LOX that condenses on the outside runs to one edge of
the bottom to form a nice drop. He then lights a wooden match, blows it out so
that just an ember is left, and touches it to the LOX drop, causing the match
to burst back into flame.

He also experimented with LN2-driven rockets, as recounted here:
http://www.armory.com/~spcecdt/pyrotech/cryoRocket_icb.html

A bit of advice: If you put out styrofoam bowls of LN2 to allow party-goers to
play with it, and there are also gummy bears present at this party, expect said
party-goers to discover that gummy bears shatter wonderfully when brought to
LN2 temperature and thrown on the floor or hammered with a mallet, with tiny
bits of gummy bear flying in all directions. Also expect to have a terribly
sticky mess to clean up the next day.

A serendipitous discovery: If you carefully cool down ethanol of very high
proof by adding LN2 directly to it while stirring, before it freezes it will
become glassy. The higher the proof, the easier this is to do. In my
experiments, anything less than 80% (160 proof) would transition directly from
low-viscosity liquid to solid. With 95% alcohol, it's easy to bring it to
the glassy state; with intermediate concentrations it can be done if you are
very careful and proceed slowly. A scoop of glassy alcohol dripping slowly off
of the spoon in long strands is a sight to behold. Of course, there is a
temptation to taste it, but be careful or you will end up with a blister on the
tip of your tongue (cough).

He recently wrote: "I finally scanned in some pictures I took of the stuff I
sent you a long while ago. They're at http://www.armory.com/~images/?s=LN2fun"


# The next idea was sent so me by Sasha Ivanov

LN is used in cosmetics to treat acnes, various skin diseases and hair loss due to
over active sebaceous (oil producing) glands. Wrap the stick with cotton, deep the
stick in LN and roll it back and forth over your skin or scalp. The cold causes
glands to shrink, stabilizing HP balance of the scalp. Your hair will grow four
times faster and healthier.


# The following idea was mailed to me by Steve Rohl (Senior _at_ Euclid High School)
who also likes to experiment with lqN2 together with his friend Ross James Salupo:

Let me start out by saying what can't you do with liquid nitrogen! But my
chemistry teacher showed me many things to do with it, such as exploding a 2
liter bottle and blowing it out of is mouth. But someting I don't think I saw
on your site was, putting a nice bloomed rose or flower in it and when you
squeeze it, it just crumbles. If thats not entertaining enough for you, another
thing you can do is, Light the floor on fire. All you need is a methane pump and
a test tube with a two holed stopper. Put glass rod in the holes. Connect a
rubber hose to one of the glass rods and also to the methane. Turn on the gas
and it'll go into the test tube and after 4 min or so, you will have a good
amount of liquid methane (of course the test tube has to be placed in a container
of liquid nitrogen). Now quickly take the test tube out of the liquid nitrogen
dump it on the floor and light. This isn't quite as dangerous as it sounds.
But every saftey measure should be taken...


# The following email reached me by Lasse Greiner

Wir benutzen LN2 für Hochzeiten statt Reis. Wenn das Pärchen aus dem Amt/Kirche
kommt schütten wir 2-3 Dewarkannen (a 25L) aus. Der entstehende Nebel ist ein sehr
netter Effekt, und die Abkühlung ist im Sommer auch willkommen...

Nur im Freien, und nicht in irgendwelchen Senken oder so probieren!
Und nicht fragen was das kostet ;-)

Englisch:
We use LN2 instead of rice at weddings. When the couple is leaving the building,
we pour 2-3 Dewars (each approx 25L) on the ground. The fog is a neat effect and
the cooling is appreciated in summer times.....

Outside only, and never try this in a valley of some kind.
And do not ask about the cost ;-)

PS: Ein sehr einfaches Schokoeisrezept (Kalorienbombe)

1 Glas Nutella o.ä.
250g Sahne
1 Pk Vanillinzucker

Nutella erwärmen, in der Sahne mit Vanillezucker auflösen.
In LN2 eintropfen, je kleiner die Tropfen desto besser.
Im Gefrierschrank (-20°C,über Nacht) auftauen lassen.


# James Jackson told me the following little anecdote:

We were using LN2 in a lab the other day to cool stuff down, surprisingly.
I managed to tip a load onto my trousers. Of course it began boiling off,
with clouds of 'smoke' coming off. Just at this point, when I was walking
around the lab with dramatically smoking trousers, a tour group of prospective
students walked into the lab. We all went about as if nothing was strange,
which confused the hell out of the tour group! Suffice it to say when they
left we pissed ourselves laughing.

The fun we have in otherwise dull labs.


# Someone sent me a quite some list of funny and silly things to do with liquid nitrogen:

1. Blu-Tack nails hammered into the wall
Because liquid nitrogen is so very cold, things that are normally soft are
changed in surprising and amusing ways. Blu-Tack, normally like putty, can
be shaped by hand into the shape of nails, which when put into liquid
nitrogen go hard (as nails) and can then be hammered into the wall (well,
if the wall is fairly soft). Of course, liquid nitrogen soon evaporates
and the nails warm up, and nails made of Blu-Tack turn back into ordinary
soft Blu-Tack, leaving a situation which seems to other people IMPOSSIBLE!
How has someone made a nail of soft Blu-Tack and nailed it into the wall?

Similarly I once made a cutting tool out of Blu-Tack, put it on a
power-drill and cut a notch in a desk. Next time you see notches in
university desks, you may wonder how they've been done!

2. Explosives that disappear into thin air
I urge caution here, as the letting off of explosions should always be done
in good humour! Seeing a bomb go off - great fun, but ending up dead or in
the accident & emergency dept NOT FUNNY, especially if you've got a really
stupid story to tell when they say "how did this happen?". Anyway, liquid
nitrogen, about 50ml of it, in a plastic lemonade bottle. At room temperature,
liquid nitrogen boils, expanding like steam to fill a volume 2000 times its
liquid state. The plastic bottle explodes very violently. being nearer than
30ft is NOT RECOMMENDED! Boom! It explodes in a great cloud of frozen steam
and ice-vapour! The plastic of the bottle is brittle like broken glass and
smashes into smithereens, tiny shards going all over the place. Then the scene
clears and all the liquid nitrogen literally DISAPPEARS INTO THIN AIR. So,
explosion investigators will find remnants of a violent explosion but
absolutely no trace of any explosives.

3. Rockets too can be made. As in "the advanced gas-cooled Lilt bottle".

4. Solid lumps of pure frozen Antifreeze
Antifreeze is a liquid deliberately for preventing freezing. Even dilute
quantities in car radiators can save your engine from being destroyed by
frost. Even the most severe winter will not freeze a quite strong solution
of antifreeze in water. But pure antifreeze, surely that could never be
frozen? Not so! Liquid nitrogen will freeze it solid! Pure solid blue crystal
lumps of antifreeze - a sight to be seen!

5. What if it gets in your carpet?
Liquid nitrogen is as wet as water, so it will soak material. On a solid
floor it will skitter about like globules of water on a cooker hotplate,
as the floor at room temperature is from a nitrogenous perspective as hot
as a hotplate. They hover around like tiny hovercraft on their own cushions
of evaporating fluid. A carpet is a bit different, and the stuff will soak
right through. For this reason it is best to make sure it's a good quality
carpet and not foam-backed, as the foam will shatter! Good quality carpets
aren't harmed by liquid nitrogen (except for really ancient fibre carpet).
Chewing gum in contrast turns to something hard and brittle, so with a hammer
it can be smashed! This is a novel way to remove sticky icky gooey things
from carpets.

6. Drinking liquid nitrogen
Not recommended! It's about as advisable as fire-eating! However I can do
it because I know how tiny a quantity of liquid nitrogen to drink such that
I avoid exploding! Even a few ml, swallowed, results in belching forth great
clouds of ice-vapour, an excellent party trick! Getting it wrong, though,
would be very nasty. I have found that when doing something really silly
it is best to be sensible in the silliness! If I was being charged up to
a million volts so I could spike my hair I'd be very careful not to touch
anything connected to electrical earth.

7. Rubber
Rubber; flexible, bouncy, stretchy, springy... but with liquid nitrogen it
becomes a hard solid a bit like porcelain. Rubber tubes, such as those
found on bunsen burners, if dipped in liquid nitrogen, turn into thin pottery
tubes and can be smashed! Then when they warm up, the broken pieces are still
in the shape of smashed shards but are now made of flexible rubber again.
A curious irony.

8. Killing weeds in the garden
Weeds growing inbetween slabs on paths? No problem! A quick dose of liquid
nitrogen freezes them solid! Weeds in garden paths do not survive being
frozen to minus 196 degrees C and then melting in the sun. However, the
liquid nitrogen is not a poison or a chemical as such and will completely
disappear into thin air. As a result, there is no residue. The sterile
ground will soon get new seeds dropped on it, so the technique of using
liquid nitrogen as weedkiller is not a permanent solution. What's more,
though the weeds will come back, your liquid nitrogen will not.

9. Whistling Kettles
If a whistling kettle is filled with liquid nitrogen it will soon boil,
even if just left in the room with no heating applied. A boiling kettle
with no heating. It will even whistle and boil in the deep freezer, as the
liquid is boiling at room temperature, so the room and the freezer are
like an oven in relative terms.

10. The tale of the exploding Fairy Liquid
This happened in a room in a student hall of residence. I already knew
from experience at a student party that if liquid nitrogen is put in a
bottle of Fairy Liquid then after an effective delay the top will burst off
and hit the ceiling! So, attempting to repeat this in my student room I
borrowed the bottle of dish washing liquid from the communal kitchen and
placed it in the middle of the carpet where my friends gathered around the
room could observe the stunt without (much) danger. Now I'm sure the people
who make Fairy Liquid will nod in agreement here about the wisdom of buying
a good quality washing-up liquid like Fairy Liquid and not some cheap brand.
Because Fairy Liquid is the top-of-the-range stuff and is a bit more
expensive, the bottle is more sturdy. The borrowed bottle of shop's own
brand was not just cheaper soapy stuff, but a lesser-engineered bottle. What
happened next was observed by the onlookers who will not forget, as the
liquid nitrogen boiled away and the bottle started to expand, bloating out
like a balloon. At last it could take it no more, and suddenly BURST! The
contents, a mixture of liquid nitrogen and soap-liquid went all over the
carpet!
The nitrogen disappeared within minutes. But how do you clean liquid soap
out of a carpet? Use muck? In the end it was never finally resolved,
although some of the bravest attempts took place on a Friday night. It was
a known fact that the cleaners never visited over the weekend, and the
heating was always on full because the tower had no separate room controls
and therefore had to be heated to the most tropical temperatures so as to
please all the residents, some of whom were from very hot places. So, on a
Friday night, the twenty gallon transformer wagon on wheels (which just
happened to be about) was filled with water and was overturned onto the
carpet! This produced loads of suds which could be trampled around in, but
the stuff was never exhausted. So, if you're staying in a student hall of
residence, you might like to test your carpet to see if it's been soaked
in soap.

11. Case of mistaken identity - The Wrong Pie
It was usual to collect food from the refectory and leave it lying around
in the rooms. Because of this, some of the food lying about on plates in
rooms was fresh, and some of it was stale. It never really went bad, but
because of the high temperatures and dry air it would become preserved and
dried-out. On that day I had put a small amount of liquid nitrogen in a
champagne bottle and had put the cork in (caution! Silliness!), and I aimed
it at a slice of cherry tart which had been lying around for a week or two
and I had decided was a bit too stale and was ready to throw out of the
window of the high tower to the birds. The cork shot out like a bullet, as
expected, and hit the cherry tart with just the right amount of force so as
not to smash the plate. But oh shucks, I suddenly realised the mistake and
saw the actual stale cherry tart on the bookshelf. I had shot the wrong
pie! The shot pie was the fresh one I had acquired that day! What a mess!
I hate wasting food! It really won't do! So I got a spoon and went around
carefully eating it off the chairs, curtains, carpets, etc, being very
careful to avoid eating any industrial grit and other stuff that had been
produced by some of the other silly experiments that had been done in that
room. It was an hour before I had got all the pie eaten. Not good, as I
could have put that time into studying something scientific.
So, the moral is: When aiming a champagne bottle with liquid nitrogen at
a cherry tart, make sure to identify the correct target first!


Attention! Working with liquid nitrogen may be dangerous!!! I hereby state that I am not liable or take any responsibility for damages or injuries caused by information or suggestions on this blog!

The funny side of Engineering (esp. software engineering)

The following is a rather extensive list of jokes relating to engineers in general. Enjoy!

You walk into a room and notice that a picture is hanging crooked. You...

Straighten it.
Ignore it.
Buy a CAD system and spend the next six months designing a solar-powered, self-adjusting picture frame while often stating aloud your belief that the inventor of the nail was a total moron.

The correct answer is "3" but partial credit can be given to anybody who writes "It depends" in the margin of the test or simply blames the whole stupid thing on "Marketing."

SOCIAL SKILLS

Engineers have different objectives when it comes to social interaction.

"Normal" people expect to accomplish several unrealistic things from social interaction:
Stimulating and thought-provoking conversation.
Important social contacts.
A feeling of connectedness with other humans.

In contrast to "normal" people, engineers have rational objectives for social interactions:
Get it over with as soon as possible.
Avoid getting invited to something unpleasant.
Demonstrate mental superiority and mastery of all subjects.

FASCINATION WITH GADGETS

To the engineer, all matter in the universe can be placed into one of two categories: (1) things that need to be fixed, and (2) things that will need to be fixed after you've had a few minutes to play with them.
Engineers like to solve problems. If there are no problems handily available, they will create their own problems.
Normal people don't understand this concept; they believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.
No engineer looks at a television remote control without wondering what it would take to turn it into a stun gun. No engineer can take a shower without wondering if some sort of Teflon coating would make showering unnecessary. To the engineer, the world is a toy box full of sub-optimized and feature-poor toys.

FASHION AND APPEARANCE

Clothes are the lowest priority for an engineer, assuming the basic thresholds for temperature and decency have been satisfied. If no appendages are freezing or sticking together, and if no genitalia or mammary glands are swinging around in plain view, then the objective of clothing has been met. Anything else is a waste.

DATING AND SOCIAL LIFE

Dating is never easy for engineers. A normal person will employ various indirect and duplicitous methods to create a false impression of attractiveness. Engineers are incapable of placing appearance above function.

Fortunately, engineers have an ace in the hole. They are widely recognized as superior marriage material: intelligent, dependable, employed, honest, and handy around the house. While it's true that many normal people would prefer not to date an engineer, most normal people harbor an intense desire to mate with them, thus producing engineer like children who will have high-paying jobs long before losing their virginity.

Male engineers reach their peak of sexual attractiveness later than normal men, becoming irresistible erotic dynamos in their mid thirties to late forties. Just look at these examples of sexually irresistible men in technical professions:

Bill Gates
MacGyver
Etcetera

Female engineers become irresistible at the age of consent and remain that way until about thirty minutes after their clinical death. Longer if it's a warm day.

HONESTY

Engineers are always honest in matters of technology and human relationships. That's why it's a good idea to keep engineers away from customers, romantic interests, and other people who can't handle the truth.

Engineers sometimes bend the truth to avoid work. They say things that sound like lies but technically are not because nobody could be expected to believe them. The complete list of engineer lies is listed below.

"I won't change anything without asking you first."
"I'll return your hard-to-find cable tomorrow."
"I have to have new equipment to do my job."
"I'm not jealous of your new computer."

FRUGALITY

Engineers are notoriously frugal. This is not because of cheapness or mean spirit; it is simply because every spending situation is simply a problem in optimization, meaning that, "How can I escape this situation while retaining the greatest amount of cash?"

POWERS OF CONCENTRATION

If there is one trait that best defines an engineer it is the ability to concentrate on one subject to the complete exclusion of everything else in the environment. This sometimes causes engineers to be pronounced dead prematurely.

Some funeral homes in high-tech areas have started checking resumes before processing the bodies. Anybody with a degree in electrical engineering or experience in computer programming is propped up in the lounge for a few days just to see if he or she snaps out of it.

RISK

Engineers hate risk. They try to eliminate it whenever they can. This is understandable, given that when an engineer makes one little mistake the media will treat it like it's a big deal or something.

Examples of bad press for engineers:

Hindenberg
Space Shuttle Challenger
SPANet(tm)
Hubble space telescope
Apollo 13
Titanic
Ford Pinto
Corvair

RISK/REWARD

The risk/reward calculation for engineers looks something like this:

RISK: Public humiliation and the death of thousands of innocent people.
REWARD: A certificate of appreciation in a handsome plastic frame.

Being practical people, engineers evaluate this balance of risks and rewards and decide that risk is not a good thing.
The best way to avoid risk is by advising that any activity is technically impossible for reasons that are far too complicated to explain.

If that approach is not sufficient to halt project, then the engineer will fall back to a second line of defense: "It's technically possible but it will cost too much."

EGO

Ego-wise, two things are important to engineers:
How smart they are.
How many cool devices they own.

The fastest way to get an engineer to solve a problem is to declare that the problem is unsolvable. No engineer can walk away from an unsolvable problem until it's solved. No illness or distraction is sufficient to get the engineer off the case. These types of challenges quickly become personal -- a battle between the engineer and the laws of nature.

Engineers will go without food and hygiene for days to solve a problem. (Other times just because they forgot.) And when they succeed in solving the problem they will experience an ego rush that is better than sex -- and I'm including the kind of sex where other people are involved.

Nothing is more threatening to the engineer than the suggestion that somebody has more technical skill. Normal people sometimes use that knowledge as a lever to extract more work from the engineer. When an engineer says that something can't be done (a code phrase that means it's not fun to do), some clever normal people have learned to glance at the engineer with a look of compassion and pity and say something along these lines: "I'll ask Bob to figure it out. He knows how to solve difficult technical problems." At that point it is a good idea for the normal person to not stand between the engineer and the problem. The engineer will set upon the problem like a starved Chihuahua on a pork chop.

------------------------------------------------------------

Engineering Terms

Top Engineering Terms and Expressions
(What engineers say versus what they mean)

1. A number of different approaches are being tried.
(We are still guessing at this point.)

2. Close project coordination.
(We sat down and had coffee together.)

3. An extensive report is being prepared on a fresh approach.
(We just hired three punk kids out of school.)

4. Major technological breakthrough!
(It works OK, but looks very hi-tech!)

5. Customer satisfaction is believed assured.
(We are so far behind schedule, that the customer will take anything.)

6. Preliminary operational tests were inconclusive.
(The darn thing blew up when we threw the switch.)

7. Test results were extremely gratifying!
(Unbelievable, it actually worked!)

8. The entire concept will have to be abandoned.
(The only guy who understood the thing quit.)

9. It is in process.
(It is so wrapped in red tape that the situation is completely hopeless.)

10. We will look into it.
(Forget it! We have enough problems already.)

11. Please note and initial.
(Let's spread the responsibility for this.)

12. Give us the benefit of your thinking.
(We'll listen to what you have to say as long as it doesn't interfere with
what we have already done or with what we are going to do.)

------------------------------------------------------------

The Train Ride

Three engineers and three accountants are traveling by train to a conference. At the station, the three accountants each buy tickets and watch as the three engineers buy only a single ticket.

"How are three people going to travel on only one ticket?" asks an accountant. "Watch and you'll see," answers an engineer. They all board the train. The accountants take their respective seats but all three engineers cram into a restroom and close the door behind them.

Shortly after the train has departed, the conductor comes around collecting tickets. He knocks on the restroom door and says, "Ticket, please." The door opens just a crack and a single arm emerges with a ticket in hand. The conductor takes it and moves on.

The accountants saw this and agreed it was quite a clever idea. So after the conference, the accountants decide to copy the engineers on the return trip and save some money (being clever with money, and all). When they get to the station they buy a single ticket for the return trip.

To their astonishment, the engineers don't buy a ticket at all. "How are you going to travel without a ticket?" asked one perplexed accountant.

"Watch and you'll see," answered an engineer. When they board the train the three accountants cram into a restroom and the three engineers cram into another one nearby. The train departs.

Shortly afterward, one of the engineers leaves his restroom and walks over to the restroom where the accountants are hiding. He knocks on the door and says, "Ticket, please."

------------------------------------------------------------

The Balloonist

A man is flying in a hot air balloon and realizes he is lost. He reduces height and spots a man down below. He lowers the balloon further and shouts, "Excuse me, can you tell me where I am?"

The man below said, "Yes, you're in a hot air balloon, hovering 30 feet above this field."

"You must be an engineer," said the balloonist.

"I am," replied the man. "How did you know?"

"Well," said the balloonist, "everything you have told me is technically correct, but it's of absolutely no use to anyone."

The man below said, "You must be in management."

"I am," replied the balloonist, "but how did you know?"

"Well," said the man, "you don't know where you are, or where you're going, but you expect me to be able to help. You're in the same position you were before we met, but now it's my fault."

------------------------------------------------------------

Wife or Mistress

An architect, an artist, and an engineer were discussing whether it was better to spend time with the wife or a mistress.

The architect said he enjoyed time with his wife, building a solid foundation for an enduring relationship.

The artist said he enjoyed time with his mistress, because of the passion and mystery he found there. The engineer said, "I like both."

"Both?" asked the architect and artist in unison.

The engineer replied, "Yeah. If you have a wife and a mistress, they will each assume that you are spending time with the other woman, so you can go to the office and get some work done."

------------------------------------------------------------

Engineering Patients

Five surgeons were taking a coffee break. The first surgeon said, "Accountants are the best to operate on because when you open them up, everything inside is numbered."

The second surgeon said, "Nah, librarians are the best. Everything inside them is in alphabetical order."

The third surgeon responded, "Try electricians, man! Everything inside them is color coded."

Then the fourth doctor interceded, "I prefer lawyers. They're heartless, spineless, gutless and their heads and their butts are interchangeable."

To which the fifth surgeon, who had been quietly listening to the conversation, replied, "I like engineers. They always understand when you have a few parts left over at the end."

------------------------------------------------------------

Three Freshman Engineers

Three freshman engineering students were sitting around one day arguing about who might've designed the human body.

The first one said, "It must've been a mechanical engineer. The human body has all those levers and pivots and stuff - a mechanical engineer must have designed all that."

The second one said, "No, it had to have been an electrical engineer. The complex way the nerves are wired up to the brain must have been designed by an electrical engineer."

Then the third one said, "No, it was a civil engineer. Who else would have run a waste water line through a recreational area?"

------------------------------------------------------------

Engineer and His Dog

Four men were bragging about how smart their dogs are. The first man was an Engineer, the second man was an Accountant, the third man was a Chemist, and the fourth man was a Government Worker.

To show off, the Engineer called to his dog. "T-Square, do your stuff." T-Square trotted over to a desk, took out some paper and a pen, and promptly drew a circle, a square, and a triangle. Everyone agreed that was pretty smart.

But the Accountant said his dog could do better. He called his dog and said, "Slide Rule, do your stuff." Slide Rule went out into the kitchen and returned with a dozen cookies. He divided them into 4 equal piles of 3 cookies each. Everyone agreed that was good.

But the Chemist said his dog could do better. He called his dog and said, "Measure, do your stuff." Measure got up, walked over to the fridge, took out a quart of milk, got a 10 ounce glass from the cupboard and poured exactly 8 ounces without spilling a drop. Everyone agreed that was good.

The Government Worker called to his dog and said, "Coffee Break, do your stuff." Coffee Break jumped to his feet, ate the cookies, drank the milk, shit on the paper, sexually assaulted the other three dogs, claimed he injured his back while doing so, filed a grievance report for unsafe working conditions, put in for Worker's Compensation, and went home on sick leave.

------------------------------------------------------------

Slow Golfers

A pastor, a doctor and an engineer were waiting one morning for a particularly slow group of golfers.
The engineer fumed, "What's with these guys? We must have been waiting for 15 minutes!"
The doctor chimed in, "I don't know, but I've never seen such ineptitude"
The pastor said, "Hey, here comes the greens-keeper. Let's have a word with him."

[dramatic pause]

"Hi George. Say, what's with that group ahead of us? They're rather slow, aren't they?"
The greens-keeper replied, "Oh, yes, that's a group of blind firefighters. They lost their sight saving our clubhouse from a fire last year, so we always let them play for free anytime."
The group was silent for a moment.

The pastor said, "That's so sad. I think I will say a special prayer for them tonight."

The doctor said, "Good idea. And I'm going to contact my ophthalmologist buddy and see if there's anything he can do for them."

The engineer said, "Why can't these guys play at night?"

------------------------------------------------------------

Engineers and Glasses

To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the engineer, the glass is twice as big as it needs to be.

------------------------------------------------------------

Clothes

Two engineering students were walking across campus when one said, "Where did you get such a great bike?"

The second engineer replied, "Well, I was walking along yesterday minding my own business when a beautiful woman rode up on this bike. She threw the bike to the ground, took off all her clothes and said, "Take what you want."

The first engineer nodded approvingly, "Good choice; the clothes probably wouldn't have fit."

------------------------------------------------------------

Retired Engineer

There was an engineer who had an exceptional gift for fixing all things mechanical. After serving his company loyally for over 30 years, he happily retired.

Several years later the company contacted him regarding a seemingly impossible problem they were having with one of their multimillion dollar machines. They had tried everything and everyone else to get the machine to work but to no avail. In desperation, they called on the retired engineer who had solved so many of their problems in the past.

The engineer reluctantly took the challenge. He spent a day studying the huge machine. At the end of the day, he marked a small "x" in chalk on a particular component of the machine and stated, "This is where your problem is".

The part was replaced and the machine worked perfectly again.

The company received a bill for $50,000 from the engineer for his service. They demanded an itemized accounting of his charges. The engineer responded briefly:

One chalk mark: $1

Knowing where to put it: $49,999

It was paid in full and the engineer retired again in peace.

------------------------------------------------------------

Fixing things

Normal people believe that if it ain't broke, don't fix it.
Engineers believe that if it ain't broke, it doesn't have enough features yet."

------------------------------------------------------------

Types of Engineers

What is the difference between Mechanical Engineers and Civil Engineers?
Mechanical Engineers build weapons, Civil Engineers build targets.

------------------------------------------------------------

Talking Frog

An engineer was crossing a road one day when a frog called up to him and said, "If you kiss me, I'll turn into a beautiful princess".
He bent over, picked up the frog and put it in his pocket. The frog spoke up again and said, "If you kiss me and turn me back into a beautiful princess, I will stay with you for one week."

The engineer took the frog out of his pocket, smiled at it and returned it to the pocket. The frog then cried out, "If you kiss me and turn me back into a princess, I'll stay with you and do ANYTHING you want." Again the engineer took the frog out, smiled at it and put it back into his pocket.

Finally, the frog asked, "What is the matter? I've told you I'm a beautiful princess, that I'll stay with you for a week and do anything you want. Why won't you kiss me?"

The engineer said, "Look I'm an engineer. I don't have time for a girlfriend, but a talking frog, now that's cool.

------------------------------------------------------------

Too Smart for His Own Good

They were leading a priest, a drunkard and an engineer to the guillotine. They asked the priest if he wanted to face up or down when he met his fate. The priest said that he would like to face up so he would be looking towards heaven when he died. They raised the blade of the guillotine, released it, it came speeding down and suddenly stopped just inches from his neck. The authorities took this as divine intervention and released the priest.

Next the drunkard came to the guillotine. He also decided to die face up hoping that he would be as fortunate as the priest. They raised the blade of the guillotine, released it, it came speeding down and suddenly stopped just inches from his neck. So they released the drunkard as well.

The engineer was next. He too decided to die facing up. They slowly raised the blade of the guillotine, when suddenly the engineer said, "Hey, I see what your problem is."

------------------------------------------------------------

You might be an engineer if . . .

. . . you have no life and can prove it mathematically.

. . . you enjoy pain.

. . . you know vector calculus but you can't remember how to do long division.

. . . you chuckle whenever anyone says “centrifugal force.”

. . . you've actually ever used every single function on your graphing calculator.

. . . when you look in the mirror, you see an engineering major.

. . . it is sunny and 70 degrees outside, and you are working on a computer.

. . . you frequently whistle the theme song to “MacGyver.”

. . . you always do homework on Friday nights.

. . . you know how to integrate a chicken and can take the derivative of water.

. . . you think in “math.”

. . . you've calculated that the World Series actually diverges.

. . . you hesitate to look at something because you don't want to break down its wave function.

. . . you have a pet named after a scientist.

. . . you laugh at jokes about mathematicians.

. . . the Humane Society has had you arrested because you actually performed the Schroedinger's Cat Experiment.

. . . you can translate English into Binary.

. . . you can't remember what's behind the door in the science building which says "Exit.”

. . . you have to bring a jacket with you, in the middle of summer, because there's a wind-chill factor in the lab.

. . . you are completely addicted to caffeine.

. . . you avoid doing anything because you don't want to contribute to the eventual heat-death of the universe.

. . . you consider any non-science course “easy.”

. . . when your professor asks you where your homework is, you claim to have accidentally determined its momentum so precisely, that according to Heisenberg it could be anywhere in the universe.

. . . the “fun” center of your brain has deteriorated from lack of use.

. . . you'll assume that a “horse” is a “sphere” in order to make the math easier.

. . . you can name 6 Star Trek episodes.

. . . you have used coat hangers and duct tape for something other than hanging coats and taping ducts.

. . . you've modified your can-opener to be microprocessor driven.

. . . you've ever saved the power cord from a broken appliance.

. . . you've a habit of destroying things in order to see how they work.

. . . your I.Q. number is bigger than your weight.

. . . the microphone or visual aids at a meeting don't work, and you rush up to the front to fix it.

. . . you can type 70 words a minute but can't read your own handwriting.

. . . you thought the real heroes of Apollo 13 were the mission controllers.

. . . you spend more time on your home computer than your car.

. . . you think that when people around you yawn, it's because they didn't get enough sleep.

. . . you know what http:/ stands for.

. . . you've ever tried to repair a $5.00 radio.

. . . your three year old son asks why the sky is blue and you try to explain atmospheric absorption theory.

. . . at Christmas, it goes without saying that you will be the one to find the burnt-out bulb in the string

. . . you have "Dilbert" comics displayed anywhere in your work area

. . . you carry on a one-hour debate over the expected results of a test that actually takes five minutes to run

. . . a team of you and your co-workers have set out to modify the antenna on the radio in your work area for better reception

. . . you are aware that computers are actually only good for playing games, but are afraid to say it out loud

. . . you see a good design and still have to change it

. . . the salespeople at Circuit City can't answer any of your questions

. . . you rotate your screen savers more frequently than your automobile tires

. . . your favorite James Bond character is "Q".

. . . you take a cruise so you can go on a personal tour of the engine room.

. . . you think "cuddling" is simply an unproductive application of heat exchange

. . . you have trouble writing anything unless the paper has horizontal and vertical lines.

. . . you have more than one constant memorized.

. . . you understood more than five of the above.

------------------------------------------------------------

Q: What is the definition of an engineer?
A: Someone who solves a problem you didn't know you had, in a way you don't understand.

------------------------------------------------------------

Q: How do you drive an engineer completely insane?
A: Tie him to a chair, stand in front of him, and fold up a road map the wrong way.

------------------------------------------------------------

A mechanical engineer, an electrical engineer, and a software engineer are in a car that breaks down.
The mechanical engineer says: ''Maybe is's a stuck valve''.
The electical engineer says: ''Maybe it's a dead battery''.
The software engineer says: ''I know. Let's all get out and get back in again, and see if that fixes it''.

------------------------------------------------------------

What's the difference between an engineer and a computer scientist?

An engineer thinks there's 1000 bytes in a kilobyte, and a computer scientist thinks there's 1024 meters in a kilometer.

------------------------------------------------------------

An engineer and a programmer

A programmer and an engineer are sitting next to each other on a long flight from Los Angeles to New York.

The programmer leans over to the engineer and asks if he would like to play a fun game.

The engineer just wants to take a nap, so he politely declines and rolls over to the window to catch a few winks.

The programmer persists and explains that the game is real easy and is a lot of fun. He explains "I ask you a question, and if you don't know the answer, you pay me $5. Then you ask me a question, and if I don't know the answer, I'll pay you $5."

Again, the engineer politely declines and tries to get to sleep.

The programmer, now somewhat agitated, says, "OK, if you don't know the answer you pay me $5, and if I don't know the answer, I'll pay you $100!"

This catches the engineer's attention, and he sees no end to this torment unless he plays, so he agrees to the game.

The programmer asks the first question. "What's the distance from the earth to the moon?" The engineer doesn't say a word, but reaches into his wallet, pulls out a five dollar bill and hands it to the programmer.

Now, it's the engineer's turn. He asks the programmer "What goes up a hill with three legs, and comes down on four?"

The programmer looks up at him with a puzzled look. He takes out his laptop computer and searches all of his references. He taps into the Airphone with his modem and searches the net and the Library of Congress. Frustrated, he sends e-mail to his co-workers--all to no avail.

After about an hour, he wakes the Engineer and hands him $100. The engineer politely takes the $100 and turns away to try to get back to sleep. The programmer, more than a little miffed, shakes the engineer and asks "Well, so what's the answer?" Without a word, the engineer reaches into his wallet, hands the programmer $5, and turns away to get back to sleep.

------------------------------------------------------------

Top Ten Reasons To Date an Engineer

The world does revolve around us... We pick the coordinate system.
Find out what those other buttons on your calculator do.
We know how to handle stress and strain in our relationships.
Parents will approve.
Help with your math homework.
Can calculate head pressure.
Looks good on a resume.
Free body diagrams.
High starting salary.
Extremely good looking

------------------------------------------------------------

Top Ten Reasons NOT to Date an Engineer

T-shirt and jeans are their formal dress. Hot dog and a six-pack is their seven-course meal.
The only social life known of is to post and talk on the net.
Flames like a monster and speaks like a pussycat.
Works from 6:30am to 7:30pm daily. No morning kisses and no evening walks.
No matter how hard you cry and how loud you yell, he just sits there calmly discussing your emotion in terms of mathematical logic.
Only listens to classic rock. Hates everything from Bach to Prince.
Touches his computer more often than you.
Talks in acronyms.
Can't leave that damn pencil off his ear for a minute.
Will file a divorce if you call him in the middle of debugging.

------------------------------------------------------------

More Reasons to Date an Engineer

Complimentary Tutoring
Large Earning Potential
Can handle stress and strain in relationships
Know all the dynamics of relative motion
Learn about the benefits of friction and viscosity
FREE body diagrams
Always back up their hard drives
Trained to do it right the first time
Specialized in experimentation
Can go all night with no hint of fatigue

------------------------------------------------------------

"You can't spell Geek without EE."

------------------------------------------------------------

The graduate with a Science degree asks, "Why does it work?"

The graduate with an Engineering degree asks, "How does it work?"

The graduate with an Accounting degree asks, "How much will it cost?"

The graduate with a Liberal Arts degree asks, "Do you want fries with that?"

------------------------------------------------------------

A Software Engineer, a Hardware Engineer and a Departmental Manager were on their way to a meeting in Switzerland. They were driving down a steep mountain road when suddenly the brakes on their car failed. The car careened almost out of control down the road, bouncing off the crash barriers, until it miraculously ground to a halt scraping along the mountainside. The car's occupants, shaken but unhurt, now had a problem: they were stuck halfway down a mountain in a car with no brakes. What were they to do?

"I know", said the Departmental Manager, "Let's have a meeting, propose a Vision, formulate a Mission Statement, define some Goals, and by a process of Continuous Improvement find a solution to the Critical Problems, and we can be on our way."

"No, no", said the Hardware Engineer, "That will take far too long, and besides, that method has never worked before. I've got my Swiss Army knife with me, and in no time at all I can strip down the car's braking system, isolate the fault, fix it, and we can be on our way."

"Well", said the Software Engineer, "Before we do anything, I think we should push the car back up the road and see if it happens again."

------------------------------------------------------------

A mathematician, a physicist, and an engineer were in a hotel for a convention. In the middle of the first night, for no apparent reason, a fire breaks out in the engineer's wastebasket. The engineer rushes over to the bathroom, empties out the ice bucket, fills it with water and pours it into the trash can, dousing the fire. Satisfied that the problem was solved, the engineer goes back to sleep. In the middle of the second night, a fire breaks out in the physicist's wastebasket. The physicist whips out his calculator and a note pad, frantically does a few computations, rushes to the bathroom, pulls out a cup, fills it to a precisely measured level, and rushes back to the wastebasket, pouring the water onto the fire. As the last drop hits the flame, the fire goes out. Satisfied that the problem was solved, the physicist goes back to sleep. Finally, a fire breaks out in the mathematician's room. The mathematician rushes to the bathroom, sees the ice bucket, sees a cup, sees the water faucet. He takes out his calculator and a note pad and calmly does the computations, working out exactly how much water is needed to put out a fire of that size. Satisfied that the problem is solved, he goes back to sleep.

------------------------------------------------------------

Top Ten Things Engineering School didn't Teach You

There are at least 10 types of capacitors.
Theory tells you how a circuit works, not why it doesn't work.
Not everything works according to the specs in the databook.
Anything practical you learn will be obsolete before you use it, except the complex math, which you will never use.
Engineering is like having an 8 a.m. class and a late afternoon lab every day for the rest of your life.
Overtime pay? What overtime pay?
Managers, not engineers, rule the world.
Always try to fix the hardware with software.
If you like junk food, caffeine and all-nighters, go into software.
Dilbert is not a comic strip, it's a documentary.

------------------------------------------------------------

Engineers do it with precision.
Electrical engineers are shocked when they do it.
Electrical engineers do it on an impulse.
Electrical engineers do it with large capacities.
Electrical engineers do it with more frequency and less resistance.
Electrical engineers do it with more power and at higher frequency.
Mechanical engineers do it with stress and strain.
Mechanical engineers do it with less energy and greater efficiency.
Chemical Engineers do it in fluidized beds.
City planners do it with their eyes closed.
Petroleum engineers do it with lubrication.
Reservoir engineers do it thorougly and with lot of simulation.
Drilling engineers do it with smooth penetration aided by lubrication, frequent short wiper trips, and at the end, slug is pumped before they pull out.

------------------------------------------------------------

Pick-Up Lines to Use on Engineering Girls

I won´t stop bugging you until I get the address of your home page.
You fascinate me more than the Fundamental Theorem of Calculus.
Since distance equals velocity times time, let´s let velocity and time approach infinity, because I want to go all the way with you.
My love for you is like a concave up function because it is always increasing.
Let´s convert our potential energy to kinetic energy.
Wanna come back to my room?....and see my 166Mhz Pentium?
How about you and I go back to my place and form a covalent bond?
You and I would add up better than a Riemann Sum.
You´re sweeter than glucose.
We´re as compatible as two similar Power Macintoshes.
Why don´t we measure the coefficient of static friction between you and me?
Wanna see the programs in my HP-48GX?
Your body has the nicest arc length I´ve ever seen.
Isn´t your e-mail address beautifulgirl@mydreams.com
You´re hotter than a bunsen burner set to full!
Y ou´re the enter key on my TI-89, baby.

------------------------------------------------------------

Advantage to dating an Engineer:

If you´re into money, you have 3 main choices: Doctor, Lawyer, or Engineer. If you marry a doctor, most likely he´ll work bad hours and you´ll have a good few years but he´ll eventually run off with some good looking patient of his. Don´t want that. You could marry a Lawyer, this might last for a while, but he´ll probably dump you for his young good looking secretary. Plus he´ll take you for every dime you ever make. Definitely not good. How about an engineer? You´ll be financially stable and I bet he´ll love you a lot and never stray. You know the no. one reason I can assure this? He´ll probably never even see another woman in the workplace if he´s an engineer!

------------------------------------------------------------

Advantages to being a girl in Engineering

You never have to complain about not having any guy friends (instead you complain you never have any friends that are girls)
Never ever ever a line for the bathroom, probably the one place on earth where the men´s bathroom is used more than the womens
No catfights (an occasional brawl, but you won´t be involved, just sit back and watch)
All the professors know your face and your name
All the guys know who you are
Never a lack of guys
Someone will always have a solution to any technical problem you have.
Cars, Cars, Cars
Have you seen the bathrooms?????
Guys want to be your partner in group projects and want to sit next to you in class, because "hey I get to be the next to the girl"
When someone yells, "hey girl," you´re pretty sure it´s you.
Lots of single guys if you´re looking for someone, some very good looking ones too
It´s awesome when your guy friends won´t stop for directions if they´re lost but WILL call you for help if they have problems with homework.
Drama free, or near drama free friendships, and those with drama aren´t worth it, plenty plenty plenty more interesting people to meet
Boys with money and fun technology they are willing to share (love the plasma tv and overly monsterous computers)
You never get yelled at for taking something apart, it´s required
You get to be a minority, minority = scholarship money ..... hehehe
Guys actually hold doors open for you and are nice to you for no apparent reason

------------------------------------------------------------