• Battery operated
• Includes flashing LEDs and a buzzer
• Bell Jar gasket seals creates a vacuum
• Includes activity guide

This apparatus demonstrates that light can travel in a near vacuum, but sound does not. The cushioned bottom vacuum jar holds a buzzer with blinking LED lights. As air is evacuated out of the jar, the blinking lights are easily visible but the sound from the buzzer decreases. This provides evidence that sound needs a medium to travel through but light does not. The sound will not completely disappear but will decrease noticeably. Even without the buzzer and lights, this device can serve as a small vacuum jar for other experiments. Includes activity guide. Required but not included are 4 AAA batteries and a vacuum pump.