Today’s a lab day in my main class for the term, with a fairly involved experiment to measure the charge-to-mass ratio of the electron. This is going to be all kinds of fun, because 1) I can’t get into the room to set anything up until an hour before the start of class, and 2) SteelyKid is home sick, which means I can’t go in to pull stuff together until about an hour before the start of class. Whee!
Today’s a day to (attempt to) accentuate the positive, though, so let’s use this as a jumping-off point for a more upbeat topic, namely:
What’s the best lab you ever did in a lab science class?
This could be from any science– physics of course, but biology, chemistry, and geology have their moments, too– and “best” is totally subjective. It could be the lab that was the most fun to do, or the one that made the most interesting or precise measurement, or the one that failed in the most spectacular manner. Leave your favorite in the comments.
My personal choice is an easy one: the “Ballistic Pendulum” lab we did when I was an undergrad.
The “Ballistic Pendulum” is a technique for measuring the speed of a fast-moving projectile by firing it into a much heavier mass that is suspended to act as a pendulum. From the fact that momentum is conserved in the collision, and energy is conserved after the collision, you can use the maximum height reached by the pendulum to determine the initial speed of the projectile.
We do this in our intro mechanics classes using a PASCO set-up with a spring-loaded launcher that fires a metal ball into a metal-and-plastic pendulum, and records the angle. It’s an okay lab, but nothing too brilliant.
Back in the stone age when I was an undergrad, though, we did this with a .22 rifle and a heavy wooden pendulum. Now, that was an impressive lab… I particularly enjoyed the year when I TA’ed the lab for the pre-med class. I told them at the start of class that we would be firing a rifle in the lab, and offered them earplugs. They all laughed at me. So I set myself up in a place where I could see the whole room when the first group fired the gun, and got to watch the center of mass of the room go up by about 10cm when they heard the gunshot. Good times, good times…
Sadly, you’d never be able to do that lab today without a SWAT team busting in and screwing up the error analysis. But it did make the point very impressively.
So, what’s your favorite lab class story?
(This is not-quite a payoff to Paul A., who asked for more True Lab Stories with his DonorsChoose donation. The generation of a real Lab Story has been delayed by SteelyKid’s illness, but I’ll try to come up with something.)
My favourite lab ever was about raindrops splattering apart on different surfaces. After recording the puddle size and amount of sattelite splatters of about 1200 drops falling from four different heights our instructor was so impressed by our dedication to statistically significant boredom that we got to play around with a high speed camera.
The room in which we set it up was so small that I spent the next three hours folded in three under a table while slowly getting high because we could only get a good resolution when using halogen lights that melted the plastic around the clamps holding them. But we got some very cool movies out of it, not to mention an unmatched insight into the inner life of tortured waterdrops.
Honourable mention goes to the many brave soda bottles that gave their life to science and liquid nitrogen. Explosions ALWAYS work. For science, of course.
Sorry, people, but my fermentation lab always gets the top evaluations, and with a number of fermentation experiments bubbling away, we need only await the results, which includes the best sauerkraut ever.
Lidocaine synthesis in undergrad. They were trying to weed out the synthetic medicinal chemists from the rest of us posers with this, three week, 20 hour lab. It was brutal going through it, though it was nice that the instructors let the class know it was the same synthetic process used to industrially produce LSD…
In the end, my yield was terrible, under 30%. But in the process of getting the sample to the weighing room (there were high precision scales necessary to determine whether I got a B- or C+), I got some of the lidocaine on my hands and, subsequently, on my face. I couldn’t feel a thing for 5 or 6 hours on the right side of my face. Still makes me smile, I think…
The coolest and most sciency-looking one was definitely my phys chem lab on phosphorescence. It involved lasers AND liquid nitrogen AND glowing blue stuff. (Writing it up was kind of a pain and mostly number-crunching, though we did get very pretty results despite the shutter being broken.)
Probably the one I enjoyed most was the group project in environmental chem, where we analysed soil samples at an old battery factory for lead content. Flame spectrometry is FUN.
Ballistic pendulum here too. Just finding out that my high school had a crossbow was great, and the teacher demoed it by shooting it down the hall. (The shot itself wasn’t too impressive–he called it “the flight of the wounded duck”–but watching the hallway clear out when he aimed it was fun.)
The ballistic pendulum was a lot of fun, but — not having had it involve firing of a .22 rifle — it falls way short of another mechanics lab: rotating frame of reference. The physics lab had kind of carousel, probably about two meters across. It was a circular plate, mounted on a motor that would set it rotating. It also had cloth hung around it, mounted on the carousel so the cloth walls rotated along with it. Inside, on the plate were mounted a table in the centre and two chairs on opposite sides. Two students at a time went on the carousel, and we would be asked to do various things like throw a ball back and forth between us, and a few other things. It made centrifugal and Coriolis forces become very real.
My best lab was in freshman E&M measuring the speed of light with an analytical balance, one side having a pair of coils to give an electromagnetic force, while the other side had a capacitor to give an electrostatic force. The ratio of electric:magnetic forces gave c^2, and was within 10% on c.
the best one yet was when a friend of mine reacted to much H_2O_2 and it was splutering everywere and when we got it working right our teacher got some steel wool and burnt it in the oxygen rich bottle and braking the glass.it has been a year and we still keep “reminding” our firend of it.
as a TA i got to do the ballistic pendulum demo with the .22 cal rifle. fun!
i like the time my high school chem teacher took us outside and demo’d the thermite reaction. i think we ended up with about 200 grams of molten iron. to call it exothermic is an understatement.
sadly, that teacher recently passed away.
I also did the ballistic pendulum with the gun. Way cool. But for my money, I still prefer the torsion measurement of G–weighing the earth with four leaden balls and a very fine string. Nothing in chem lab was nearly as much fun. (I did chem lab back in the days of alchemy, when manly men crystallized solutions with their beards, and took vast manly inhalations of aromatic hydrocarbons.)
In high school chemistry we performed a mini-hindenburg lab. Looking back on it, it was probably breeding grounds for a lawsuit, but still pretty darn cool.
It wasn’t GREAT lab, but this year in my quantum physics for poets class, I devised a lab to measure e/m using an old CRT monitor, a very powerful commercial magnet, a ruler, and a crapload of simplifying back-of-the-envelope assumptions. (I have neither the budget nor the space to obtain and store a specialty e/m apparatus for this course.)
It was gratifying simply because it worked, at least in an order of magnitude sense.
I also enjoy the lab I do in my relativity-for-poets class where we measure the gaussian curvature of a big balloon by inflating it and measuring the geometric properties of circles and triangles on its surface. The students are just SO SHOCKED when those angles don’t add up to 180º, even though they should know by then to expect it.
When I read this post a few days ago, I immediately thought of when i was in junior lab and a group of us tried to fabricate bucky balls. The set up at the time was essentially two graphite rods clamed into a glass reaction chamber. At which point the whole apparatus was placed into a large cooling bath and then a current run though the rods so that they would arc. So far so good. Initial set and arcing runs according to the documented procedure. Next comes the point where the apparatus needs to be disassembled and rinsed with toluene in order to collect any bucky balls created. At this point lets mention that it is Friday around 5 oâclock. So just as we are starting to pipette the solution out the chamber we managed to break the pipette in half. Since the chemistry stores are closed for the weekend and we needed to get this done for the weekend, someone comes up with the ‘brilliant’ idea that we should mouth pipette the solution out of the chamber. Which worked and none of us have developed any health problems yet. Regrettably, after all that effort we seemed to have missed the process window and did not manage to fabricate any bucky balls. For the next two years our little group was constantly looked at with awe and caution by the chemists in the university. Though it did cement my love of experimental science. When do theorists get to talk of the adventures of an experimental mishap?
My favorite lab was one we did in high school chemistry. The experiment itself wasn’t that amazing – basically just titration, but instead of telling us what to do, our teacher gave us a little story about a farmer wanting to know how much calcium was in his chicken’s eggs, told us what chemicals we had at our disposal, and told us to go design an experiment that would let us answer his question, and then perform it. It was just so cool to feel like we were doing something actually useful and that we had the ability to figure out how to do it on our own.
Freshman fall LASER labs. Specifically, building an ultra high power ultraviolet pulse laser. Being ultraviolet, it was invisible and it took so much power the lights flickered with each shot as it made random things burst into flames. Supercooling with lasers, building a fiber optic waveguide and running simple data transfers between computers with it, and such were all pretty sweet though. Really, you can’t get cooler labs than laser labs, I mean, they’re LASERS.
You can measure the speed of light using a slab of chocolate and a microwave oven. Your kid will think your kitchen is the best lab, and that you are a great scientist.
http://www.null-hypothesis.co.uk/science/item/measure_speed_light_microwave_chocolate
I’ve been awe-struck by this one exactly 50 years. In a virology lab we killed coliphages (viruses that infect E. coli) with UV light, waited prescribed intervals from 1 minute to an hour, added host cells, plated them out, and incubated the plates. Darned if the little suckers, apparently dead at one minute, didn’t scramble around and reassemble their chromosome and come back to life, demonstrating an elegant time-regeneration curve. Never take life – or death – for granted.