Bell Jar With Battery Operated Buzzer

Without air or matter, sound waves cannot travel and therefore cannot be heard. This bell jar effectivelydemonstrates this concept using a battery€“operated buzzer housed inside an acrylic tube. When the buzzer is placed beneath the jar and a vacuum seal is created in the chamber, students will observe a total absence of sound. Once air is returned to the chamber, the sound of the buzzer can be heard once more. Activity requires an electric vacuum pump, not included. Height 14cm, dia. 10cm.