Science in the Library

On May 19, 2017, kids came to the Pasadena Public Library to make wind turbines that would generate electricity by turning the shaft of a hobby motor. We were inspired by a project we found at https://www.exploratorium.edu/snacks/light-wind . The goal was to use the motors in reverse--instead of the electricity making the shaft turn, the turning would make electricity! We hoped to produce enough energy to light an LED bulb attached to the motor. It didn't work out that way, but we still made a great science lesson of it. I provided several different motors, but every time I tested them myself, I could not get the LED light bulb to come on. One kind of motor I got at Fry's was just too strong to turn in the wind. It probably would have needed blades several feet long and a floor fan wasn't going to produce enough wind. The other kind turned easily , but didn't generate quite enough voltage. (One of the kids accurately noted: "Don't you need more energy to op...

This afternoon we had a program at Pasadena Library about how to make a musical instrument--something that would produce not just noise, but definite pitches that you could change or manipulate.  We learned about aerophones, chordophones, idiophones and membranophones, and then got a chance to make our own DIY instruments. Here was my setup: Not shown: a large container of water, which we needed for some of the instruments. First, we talked about the properties of sound and experimented with a "head harp," which is made by putting a string through a wire hanger and holding both ends up to your ears to hear what sounds it made when we let the hanger hit the wall.  Without the strings being close to your ears, all you hear is a faint click, but when the strings are held up to your ears it sounds like a gong or a church bell.  This helped to convey a lesson about how much faster and better sound moves through solids than through air. After some mo...