suitable for KS3+. A versatile unit for demonstrating the properties of a vacuum. Comprises a sturdy baseplate with tap, glass bell jar and detachable battery operated bell. The bell can be heard getting quieter as the air is evacuated. Then, by closing the tap, turning off and disconnecting the pump, and then slowly allowing the air back in, the bell can be heard getting louder, as air is required to conduct the sound.
Please Note: Use ideally with an electric vacuum pump (our code 0951) as sometimes a hand pump does not create a strong enough vacuum. 285 x 215mm.