Thermite and other memorable experiments

May 4, 2006 11:10 PM

Unsafe-science-experiments-you-did-in-class-Friday: an advisory on dangerous chemistry experiments (they mention Nitrogen Triiodide, Chromate Volcanos, Whoosh Bottles, and Potassium Chlorate and Sugar), unwise microwave oven experiments, and, of course, thermite (and a great thermite video). I am amazed anyone survives high school, what other dubious but educational experiments did you do? Note: all pages are science education sites. Read the warnings. The awesome Chemistry Comes Alive site mentioned prev.
posted by blahblahblah (44 comments total)

You can have lots of fun with sodium metal. It's great for the plumbing, of course.
posted by Steven C. Den Beste at 11:26 PM on May 4, 2006

Not dangerous, but we used to pour silver nitrate on some unsuspecting fool's arm. They would think it was just water, only to their arm turn black as it was exposed to sunlight after class. Good times. That stuff doesn't come off for days.
posted by diocletian at 11:31 PM on May 4, 2006

When I was in junior high school, a friend and I found out about Nitrogen Triiodide. We spent a LOT of time trying to figure out if we could make a batch of the stuff...
posted by Windopaene at 11:35 PM on May 4, 2006

I totally forgot to include in the FPP the strange case of David Hahn, the radioactive boyscout. Building a nuclear reactor beats thermite every time.
posted by blahblahblah at 11:50 PM on May 4, 2006

We had some fun with LOX I got in Thermos bottles from flight line guys at the Naval base where my dad was stationed. This science teacher has a clever setup for producing it in small demo quantities by using commercially available liquid nitrogen as a refrigerant for condensing gaseous tank oxygen.

We also had fun with matchstick rockets.
posted by paulsc at 11:54 PM on May 4, 2006

How did they even get the Nitrogen Triiodide set up for that experiment without it exploding? That stuff looks evil.
posted by banished at 12:28 AM on May 5, 2006

A friend once swore to me that his high school or junior high science teacher (who doubled as a coach) broke open a thermometer and had the students handle the mercury bare-handed. He wanted them to see it form little balls and all that good stuff.

As I remember the story, the teacher just didn't know that mercury was poisonous.
posted by Clay201 at 12:44 AM on May 5, 2006

banished: it's only sensitive to pressure once it's dry (so they set it up while it's still wet)

great post.
posted by zanni at 1:37 AM on May 5, 2006

How did they even get the Nitrogen Triiodide set up for that experiment without it exploding? That stuff looks evil.

As zanni says, it's only explosive when dry. You can make it (at your own risk) by mixing a load of iodine crystals with some fairly concentrated ammonia solution. The resultant brownish sludge is perfectly safe while wet. Once you've dried the stuff out though, it's a different story...

It's one of those explosions that's almost 'bang' - no heat or flames. I remember a science teacher friend telling me about the time he spread a big batch of the stuff across some paper along a sunny window-sill to dry. A fly landed, and the explosion took out the window pane.
posted by popkinson at 1:53 AM on May 5, 2006

One I personally performed:

Get some lye/NaOH. Fill a 20 oz. soda bottle. Add strips of aluminum foil. The reaction produces dangerous hydrogen gas. You can fill a balloon with it, to make an explosive balloon. We were also able to get either a quick flamethrower-like burst of flame or a cool candle-like effect by introducing flame near the mouth of the bottle.
posted by TheOnlyCoolTim at 2:07 AM on May 5, 2006

Ahhhh, sweet thermite, the memories. I wonder what ever happened to the bottle of Fe2O3 we tried for this.......
Alum powder is available as radiator stop leak, though it's a bit coarse. Wonder whatever happened to rec.pyrotechnics?
posted by IronLizard at 2:44 AM on May 5, 2006

Science pranks and anecdotes
posted by edd at 2:56 AM on May 5, 2006

...my biology teacher once tried telling us about intelligent design.

not really dangerous, but definately frightening.
posted by Tryptophan-5ht at 3:27 AM on May 5, 2006

My grade 10 science teacher showed us what happens when you mis magnesium and water.

"Oh... that's probably goiing to be another hole in the floor."
posted by Space Coyote at 4:31 AM on May 5, 2006

As someone who blew up a science cupboard with Nitrogen Triiodide and was very nearly expelled from school, don't try this one at all, kids!

School science can't be any fun any more. When I were a lad, we used to (and with teacher approval):

• pop little chromate volcanoes on spatulas if there was extra time - until someone stuck a red-hot spatula back in the chromate jar.
• do this thing with phosphorus and a solvent that you could write on filter paper with a glass rod dipped in it, and it would trace your letters in fire.
• drop Dutch Metal foil into a chlorine-filled container.
• have a physics teacher who'd hand out mercury after filtering it through his pocket handkerchief, which he then proceeded to use for its designed purpose.

posted by scruss at 4:39 AM on May 5, 2006

My high school chemistry teacher had a large mason jar full of mercury. He wants us to pass it around the room to see how dense it was and about half way through the class decided this was bad idea and took it back.
posted by rabbitsnake at 5:02 AM on May 5, 2006

Thermite is fun, but it's truly amazing in very large quantities. I suggest 1500 pounds.
posted by eriko at 5:21 AM on May 5, 2006

Ah, the pryo phase. I remember it well...

A buddy and I found that if you tie lots of tight knots in underwater demolition fuse (available through the ads in Popular Science), and then wrap them tightly in tape, they would almost explode. We were throwing these out of my tree fort one day, when we noticed that way down on the ground the dry leaves surrounding the tree were on fire. Panic ensued, and over time we got down, stretched the garden hose out and mostly put it out. A fire truck came down our street during this, slowed down to look, then continued on to our neighbors house. Apparently those kids had set their yard on fire too!

Got my chemistry set taken away for two months.
posted by DesbaratsDays at 5:21 AM on May 5, 2006

My dad and I used to paint very tiny specks of Nitrogen Triiodide on the underside of all the lightswitches in the house to annoy my mom and sister. Endless fun, but you have to know what you're doing. It really is great stuff, though.
posted by Ryvar at 5:22 AM on May 5, 2006

Add me to the list of people who vividly remember playing with mercury poured directly onto an open surface.
posted by briank at 6:02 AM on May 5, 2006

I had a small box of mercury, I played with matches, I launched bottle rockets out my bedroom window, and I set the lawn on fire. But now I realize I was a piker! A PIKER!
posted by Songdog at 6:07 AM on May 5, 2006

My favorite 'my God - they used to do that?' science demonstration was showing the redox potential of ordinary lead. Metals like lead and aluminum would burst into flames if they didn't form a protecive oxide coat on their surfaces that blocks further oxygen exposure. My freshman Chem prof demonstrated this by grinding lead colloidally fine in a bath of acetone, then slowly pouring the mixture through the air while standing on a desk. As it fell, the acetone evaporated, exposing lead to oxygen. It spontaneously caught fire and made a huge mushroom-shaped cloud of red smoke, which is a very duarble toxin. Makes me wonder how many other toxic substances are caked in thin layers on the walls of university lecture halls.

Also, we used to make thermite by scraping rust from scrap iron and using aluminum foil. Not very interesting as a pyrotecnic display, but fun to see what all you can fuse together with the pool of yellow-hot molten iron that comes out the bottom.
posted by gregor-e at 6:10 AM on May 5, 2006

Ahh yes, the joys of having a college chemisty professor for a father.

Some of the more memorable moments.

Making flash paper (flash cotton). Never worked quite as well as the original stuff, but it was still fun.

Contact grenades, A shotgun shell without the buckshot, stick it in a pvc pipe, fill with wadding, add a streamer, and a bb/small ball bearing on the primer. Throw, and enjoy the paper rain (watch for falling plastic).

Using picric acid to make metal picrates. Different metals make different colors of fire. Coat a pinecone in various picrates, and toss it in a campfire. Much fun is had.

Chemi-luminescence with luminol, and making my own glowstick like substance, and seeing the look of wonder at a glowing blue car driving down the street. (but the stuff only lasted around 10 minutes once it hit air)

Tennis ball grenades. Just stuff a tennis ball full of strike anywhere match heads (and a little black powder/magnesium/etc), throw at something (preferrably not flammable, I got it right the second time), and enjoy.

Dad catching me reading the Anarchist's Cookbook, and demanding that he overlook anything I wanted to make. Found quite a few mistakes in there, so he started giving me all the good recipes.

Of course, the thermite, generic smoke grenades, etc. I learned more about fire safety in one summer than most people learn in a lifetime.

I also realize in today's climate, I would probably be locked up for the things I was allowed to try as a kid.
posted by fnord at 6:17 AM on May 5, 2006

@fnord - You used to make picrates? Jeez, that's amazngly dangerous. Picric acid is Tri-Nitro-Phenol, a very close chemical cousin of TNT, only more dangerous. Old picric acid bottles are notorious for dehydrating or forming picrate salts, becoming far more sensitive to shock. I doubt there are many chem stockrooms that still have the stuff, but I've seen old bottles that had obviously been there 50 years or so. Gave me the willys just looking at them.
posted by gregor-e at 6:36 AM on May 5, 2006

I went to school in South Carolina. We had mandatory "Hunter's Ed" as part of our physical education. Basically this involved watching reenactments of rednecks accidentally shooting themselves. The highlight was when they brought in the real, but "deactivated" (supposedly the firing pins had been removed) hunting rifles and shot guns and we practiced aiming and holding them without "sweeping" our mock hunting partner. This was done in the school's gymnasium. I can't imagine they still do this (bringing guns into school) now a days... but it's a fun story to tell all my horrified Yankee friends.
posted by wfrgms at 6:44 AM on May 5, 2006

gregor-e: yep. Remember, my father was watching all of this. We were doing it all in a lab, under the hood, proper precautions and all.

It was used as a military explosive, but was too unstable (if I remember correctly).

This stuff was all under water in the lab, so was relatively safe, but I agree. I wouldn't touch the dried stuff if you paid me.
posted by fnord at 7:04 AM on May 5, 2006

Awesome. Nice post.
posted by dazed_one at 7:07 AM on May 5, 2006

fnord - did you ever make flash powder? That was my dad's favorite (he was a chemist as well).
posted by Ryvar at 7:12 AM on May 5, 2006

We made Ammonium Dichromate volcanoes! We'd build the structure out of papier-mâché, then make a little wire cup for the top. We'd fill the cup with Ammonium Dichromate, add a bunch of pencil shavings, and let 'er rip. Beat the hell out of the silly baking-soda-and-vinegar method. Oh, sure, usually the structure caught fire, a little, but, hey, SCIENCE!
posted by MrMoonPie at 7:14 AM on May 5, 2006

I am amazed anyone survives high school, what other dubious but educational experiments did you do?

God, living must be so terrifying for you!
posted by c13 at 7:44 AM on May 5, 2006

I am amazed anyone survives high school, what other dubious but educational experiments did you do?

God, living must be so terrifying for you!

You'd be surprised! My physics teachers also blew his face off when he ignited a methane bubble a lot closer to his face than he thought it was. Priceless expression!
posted by jmd82 at 8:14 AM on May 5, 2006

Yup... I too was one of those kids (along with my lab partner) who managed to set the linoleum on fire with magnesium. But my teacher gave us a really big piece and it popped out of the beakerful of water. Hardly our fault.
posted by kimdog at 8:36 AM on May 5, 2006

Slightly less damaging was someone spreading mercury on the aluminium stair treads in school - wonderful feathery growths of amalgam.

Nitrogen triiodide - we used to put small quantities in little foil packets and leave them scattered around on the floor...
posted by ibanda at 8:52 AM on May 5, 2006

...not to mention the calcium carbide tricks!
posted by ibanda at 8:57 AM on May 5, 2006

You'd be surprised! ..... blew his face off .... Priceless expression!

What expression exactly? Must have been horrifying.
posted by dibblda at 9:42 AM on May 5, 2006 [1 favorite]

I grew up in rural Ohio, and my grandfather, a retired science teacher, used to thrill us with a derivative of this classic demonstration of why grain dust is so flammable. Dust explosions in the silos of grain elevators were a common occurence in dry seasons. My sisters and I adapted this experiment by adding Lego people or army men to represent the grain elevator employees. Good times, those.

I also employed the aforementioned drano & aluminum foil in a 2-liter bottle bombs to very nearly get myself kicked out of college.
posted by M.C. Lo-Carb! at 9:43 AM on May 5, 2006

I think some people in this thread are confusing magnesium with sodium, or possibly calcium. Magnesium does burn brightly and is quite hard to extinguish, but it does not catch on fire when it comes into contact with water; some racing wheels were made out of it because of its lightness, and you can buy keychain firestarters that are made of solid magnesium blocks (you scrape of some of the stuff and ignite it with sparks from an embedded flint).
Oh, and if you ever want to see really bright light, fill a test tube with oxygen and drop a burning piece of magnesium wire in. It's like the sun coming up on a foreign planet.
posted by PontifexPrimus at 9:49 AM on May 5, 2006

This is one I've been told about, but would never have the guts to try myself:

If you take a solution of copper sulfate and bubble acetylene through it slowly, pretty soon there will be a layer of blue powder at the bottom. Filter it to separate out the powder, and what you've got is copper acetylide.

Which apparently makes nitrogen tri-iodide look stable. As long as it's wet, it's safe to handle. What he told me was that they used to put a wet filter paper load of the stuff out into the middle of a field, and wait. Eventually it would explode (quite spectacularly) when a fly landed on it. Or if they got bored, they'd start taking shots at it (from a great distance) with a BB gun.
posted by Steven C. Den Beste at 10:11 AM on May 5, 2006 [1 favorite]

In high school chem class, we played silly games with copper nitrate and tinfoil. We were supposed to only use a tiny amount, but the teacher got interested and started using vast quantities. I forget how we explained the ceiling damage to the principal.

In middle school science, a teacher put out two beakers -- one of hydrochloric acid, one of water. We were supposed to use various tests to figure out which was which. When the teacher wasn't paying attention, one of my classmates decided to use the taste test. Luckily, he picked the water beaker first.
posted by booksandlibretti at 12:36 PM on May 5, 2006

My middle school science teacher really liked the Florida Gators, and someone gave her a gator fountain to attach to a garden hose. One day, she attached it to the gas and lit a match. That was a bad idea.

Yesterday in chemistry one of the kids in my class wanted to measure the energy released when he mixed magnesium and hydrochloric acid. As it turns out, the answer is a lot. So much in fact, that some of the hydrogen chloride came out of solution and went into the air. He saw that his experiment was releasing a gas and decided to walk away. Meanwhile everyone else was wondering what the smell was.
posted by martinX's bellbottoms at 2:41 PM on May 5, 2006

You'd be surprised! ..... blew his face off .... Priceless expression!
Oops, I meant almost blew it off, as in the explosion singed his eyebrows. It was one of those, "Wow, I almost blew my face off...that could have been bad...LETS DO IT AGAIN!!!" faces.
posted by jmd82 at 9:40 PM on May 5, 2006

I have a dim memory of some third grade teacher who was ahead of her time, allowing the kids to design and implement their own experiments. I shook flour out of a strainer over a bunsen burner. It really gave us a sense of the dust explosion thing.
Good times, good times.
posted by deep_cover at 6:28 AM on May 6, 2006

During my first year of teaching science, as a demonstration to my class, I added small amounts of solid sodium to a beaker of water and as expected it fizzed and sparked a little fire. I decided to do this twice more, but in the same beaker. Big mistake, the water was already hot, the sodium exploded the beaker, shot some small flames into the air and burnt a few tiny holes into the ceiling tiles. hmmm, note to self always use the hood while in the classroom.
Every year I demonstrate a thermite reaction . Done outside, in a metal bucket of sand, using the clay pots. I make the students stand at least 20 feet away. Last year the rxn stopped before anything happened. I waited until the smoke cleared, with great trepidation approached the bucket and picked up a piece of charred potassium permanganate with some tongs. As I picked up the char a tiny hot ember fell into the clay pot...I took off running , got about 15 ft away, slipped and fell down in front of my students just as we got a great thermite reaction. There was quite the explosion, of laughter.
posted by redhead at 2:46 PM on May 6, 2006

Luckily, he picked the water beaker first.

Actually, drinking hydrochloric acid at reasonable dilutions is fairly safe - your stomach contains plenty of the stuff already.

Some of the kids in my school used to do it for a dare - making stronger and stronger solutions and drinking them - I think they stopped when their teeth started to fizz...
posted by popkinson at 7:54 AM on May 8, 2006 [1 favorite]