Velocity Lab, Or Why We Don't Do "Real" Labs

One of the most interesting things I noticed in the PBS series Einstein's Big Idea was how the early investigators looking into physical phenomena were able to make such precise measurements using such primitive equipment and facilities. If the re-enactments are to be believed, scientists like Antoine-Laurent Lavoisier and Emilie du Châtelet were basically conducting their research in a spare room at home. It must have taken a tremendous amount of patience to gather the data that proved, for example, the principle of conservation of matter or that the energy contained in a falling object was proportional to the square of its velocity.

In this experiment, we recreated Mme. Châtelet's demonstration by dropping marbles into cups of flour from various heights and measuring how far down into the flour they sank. Although I don't usually bother recording data -- no one is particularly interested in keeping track of what we're doing besides me -- in this case I thought we'd do it "the real way," like the classroom instructions call for. But right away we had to make changes. First, we could only find yard sticks, not meter sticks. So we cobbled together a meter stick by taping a tongue depressor onto our yard stick and marking off the extra centimeters.

(Note marble in mid-flight)

Next, the lab called for regular glass marbles, but we found that our results were rather random -- the marbles fell different depths without regard to what height they were dropped from. And sometimes they barely broke the surface of the flour. So we used some steel marbles we found, which tunneled into the flour an amount that could be measured.

Finally, the regular drink-sized paper cups called for in the lab were too shallow, and the (metal) marbles hit bottom and bounced back up. So I dug out some super-sized plastic cups that were about twice as tall as the original cups.

But in the end, our data was gibberish. We were simply too careless, and we didn't do enough trials to get a reliable answer. The whole experience reminded me of my traumatic days in high school science, where the top students (the ones who went onto med school, as it happens) routinely made up data to fit the expected results, so they'd get a good grade in the class.

(Stick marked in cm for measuring depth of marble)

In the three years since I began really focusing on science, I've been very proud of myself for getting nearly all the "labs" we do to work -- by which I mean they provide an impressive demonstration of the principle I'm hoping to illustrate. But I just think it's too much to ask for these demonstrations to provide useful data as well. We're not scientists, but we like watching cool things happen. I'm sorry to admit it, but it's true.

So if you're using this blog to find ideas for your own home or classroom science activities, take our example with a grain of salt. We're dilitantes with a capital "d," and we cannot be held responsible if your results vary.

Richard Wiseman's Top 10 Quirky Science Tricks for Christmas Parties

These "stunts" aren't just great for parties, they're also perfect quick and easy science demonstrations for kids. They come from the Quirkology YouTube channel created by Prof. Richard Wiseman from the University of Hertfordshire (UK). For more quirky science visit Wiseman's blog -- but be aware the blog has some not-safe-for-the-classroom informality.

Thanks to a whole bunch of people on Twitter.

Physics at UAlbany's Community Day

When we studied Chemistry a couple years ago, we started off with a trip to see local colleges put on demonstrations for "National Chemistry Week." There's nothing like that for physics, but luckily the University at Albany's Physics Department had several demonstrations as part of the school's Community Day. We saw Lego models of the Mars Rover and other robots, some cool (sorry!) liquid nitrogen tricks, a hologram of King Kong, and a mad scientist-type Jacob's Ladder. (I couldn't help but notice how much of the department's equipment looked like it belonged in Frankenstein's lab -- I guess the nanotech money hasn't spread to the physics dept.) Still, the professors and students were very friendly and willing to answer questions, and it was cool to see some stuff we probably won't be doing at home!

This is a Jacob's Ladder. Look closely between the upright bars and you will see a spark rising up.

The magnetic rings are repelled when the current is turned on, creating a like magnet charge on the center bar.

Also a little hard to see, this is a rotating hologram which shows an animated image of King Kong dangling from the top of the Empire State building.

Dipping an inflated balloon in liquid nitrogen makes it contract. As it re-warms, the air inside expands to fill the balloon again.