ScienceMakers Toolkit Manual - The History Makers

Now to go beyond the natural frequency, you will rub the rod more aggressively. This will create a higher pitch
sound that your parents might describe as shrieking or just plain unpleasant. These vibrations are called harmonics.
Try This!
Another clever way of fi nding the center of the rod is to place it over the ends of your pointer fi ngers. Now
slowly bring your arms together while allowing your fi ngers to slide beneath the rod. The pressure of the rod on
each fi nger will adjust the amount of sliding friction so that your fi ngers will automatically come together at the
center of mass of the rod. Since the rod is uniform in shape, the center of mass is also the geometric center.
The shower in your bathroom and the stairwell of a building have the perfect acoustics for many physics experiments.
When you sing in the shower, the waves refl ect off of the walls. At certain pitches, the waves will constructively
interfere and produce a phenomenon called resonance. Try singing high and low until you fi nd the
resonant frequency of your shower. You will know it when you hear it, because resonance will make you think
that you are an opera star.
See this experiment online at: http://www.physicscentral.org/experiment/physicsathome/rod.cfm
Ronald E. Mickens - Video Clip Transcription
Clip 1 - Early Interest: My grandfather mainly talked to me about science. About what it means to be a scientist,
and how does one distinguish scientifi c knowledge from other kinds of knowledge…So we had, you know,
lots of interesting discussions. But also, I think, formed the basis of my wanting to be around people who were
much older than I. I mean, you know, why be around somebody my age, I didn’t know anything, and they probably
knew less than I did. So, you go with the people who have the knowledge.
Clip 2 - First Chemistry Set: My best ever, goodest of all Christmases, and that’s when my parents bought me
a chemistry set. I must have been about eight years old. That was something that I really wanted. You know, you
ever think back, what was the best Christmas. I mean it wasn’t, it was one of these little small things, but the
thing I liked about that Christmas gift, the chemistry set, was that you could actually kill yourself with this stuff.
See nowadays, you know, they give you these chemicals that you can swallow it, nothing happens. It’s basically
Kool-Aid. But in those days, they gave you things where you could actually blow off a face. Or you could set
the house on fi re. Or you could, you know, maim yourself or whatever. And that was good, I mean fortunately
most of the destructive power ended up being directed toward the house, but there were some close [calls], you
know. But that was fun, I mean, it was, I mean you could mix stuff up and it would actually blow up. I remember
one time, and I’m not sure what happened, I mixed up some powdered metal with some sulfur, it was basically
gunpowder and it went off in my face. But fortunately it was in a test tube and I was sitting like this, and it
went down and blew a hole in the fl oor and it missed my face because it was directed almost like a gun, it went
up to the ceiling. But that was, I mean, that’s how you get, people talk about how do you interest kids in science?
Give them some dynamite, I mean really, you know, some nitroglycerin, some acid, I mean, then, well at
least the ones that survive, they will be in science. But now you can’t get that excitement out of a video game, I
mean, no. There has to be some real danger there.
Clip 3 - Starting at Fisk: I had these full fellowships, scholarships to three or four colored schools and I decided
I wasn’t going. I mean, it’s not that I had anything against them as being colored schools, I wanted to get
out of Virginia. That was my whole thing. I had never heard of Fisk before. So I went down and this is a science
program, and we had calculus, we had chemistry, we had physics and all kinds of stuff. But at the beginning of
the summer institute, they gave us a standardized exam. And I made 99 percentile on the standardized exam. I
blew them out, as they say. The thing that’s interesting is that at the end of the summer, they gave us exactly the
same exam [as] before, and I made 92 percentile, so I told [them], this has been a negative learning experience.
193
Physics