A Rubens Tube is a physics experiment which demonstrates that sound
waves are just pressure waves. Flammable gas is fed into a tube with small holes cut along the length. A speaker
is attached at one end. The sound waves from the speaker create regions of higher and lower pressure in the tube,
which alters the amount of gas available to the fire creating areas of higher and lower flame levels. The amplitude
of the effect is related to the amplitude of the sound wave, and by altering the frequency of the sound wave, one can
produce a standing wave effect. Below are some pictures/videos of the Rubens Tube Kirsten Larson, Ryan Swindle, and I
contructed.
A lightning globe is a pretty simple and cheap project. Although it is also relatively dangerous. A high voltage (more than 5k volts) is required. You can purchase special
high voltage power souces, however, to save money we simply took apart an old monitor which runs at over 10k volts and hacked the power source. The power is run through
a gas containing bulb. In our case, the bulb had a argon-nitrogen mix. The bulb is wrapped with aluminum screen (or some other conductive material), and then run to a ground.
The high potential differences lets the current arc across the gas and through the insulating glass bulb to the aluminum screen creating the lightning effect. Pictures are below.
Monitor missing it's circuit board.
Completed Apparatus
Lightning Show!
The excited argon-nitrogen mix creates that characteristic purple color.