Jolly Air Bulb

This apparatus is designed to demonstrate to students that volume of air enclosed in the column is clearly visible to students. A wide bore glass tube is mounted vertically in front of a scale graduated 0-60 cm.

Zero corresponds to the inside of the closed top end of the tube. Air is confined in the tube by a coloured oil contained in a metal container fitted with a Bourden type gauge. A tap is fitted to the side of the metal container, for the air inlet tube from the pump. As the pressure in the oil container is increased, oil is forced into the glass tube and volume of contained air and its actual total pressure are directly indicated. The tube is of extra strong glass having very large safety overload margin. As a further precaution, a safety plastic screen is secured over the front. Overall ht. 690 mm approx. Supplied complete with oil.

Demonstration type, fully enclosed in a transparent synthetic case for demonstration. 100 mm coated dial reads from 28 to 32 inches and 950 to 1040 millibars, air tight sealed all around, pressure rubber bulb provided to force the movements, for educative demonstration.