Buzzer in a Vacuum, 1 Each

The United Scientific® Buzzer in a Vacuum by United Scientific is a classroom demonstration showing that sound needs a medium while light does not. A gasket-sealed bell jar (106 mm tall x 90 mm diameter) holds a buzzer with blinking LEDs; as air is removed, the lights stay visible and the sound fades. Includes 1 m of 6 mm ID tubing. Used in physical science and physics teaching labs.