Workshop for High School Physics TeachersAmerican Physical Society meeting
Westin Hotel Indianapolis, March 19, 2002Mike Moloney, Elaine and Scott Kirkpatrick, and Albert McGarvey
- Sample Excel Spreadsheets and Discussion
- Experiment to Determine the Wavelength of white light using a cloth grating
- Hearing 'chimes' from coathangers and other wires
- A falling magnet lights red and/or green LEDs as it passes
- magnet slides down a 1/2" pvc pipe
- the LEDs are connected across a coil around the pvc pipe
- when the magnet goes fast enough there is enough emf to light one or more LEDs
- the red LED needs a lower voltage than the green, so just the right speed lights the red but not the green LED
- list of manufacturers of the magnets and coils we used
- Making squawkers (cup and string, soda straws)
- a hole is made in the botttom of a plastic cup
- a string is put through the hole and knotted
- by pulling or scraping on the string, one makes a squawk
- or,
- one cuts the end of a soda straw into a 'V' shape
- the ends of the 'V' are supposed to be slender, and vibrate like a reed
- one blows through the 'V' and makes a sound
- as this sound is being made, one cuts off the straw shorter and shorter
- the frequency goes up as this happens, due to the shorter length
- Jello Optics
- one makes a shallow pan of jello (instructions)
- one cuts the jello into shapes and passes light from a laser pointer through the shapes
- cut a strip 1-2" wide to act as a waveguide.
- Place on a surface like transparency plastic on stiff cardboard
- send light from a laser pointer into the strip
- vary the angle and observe total internal reflection
- gently bend the strip and observe the light 'follow' the curve
- bend the strip more, and observe light losses near the bend
- cut a plano-convex lens from the pan and place on a separate surface
- use a flashlight to shine light into the 'lens' and observe focusing
- Place crossed polaroid across the width of a strip of jello
- Press gently on the jello and observe the effects of this stress using the crossed polaroids