Experimental glass blowing for boys

by Carleton John Lynde

FIG. 100
MAGIC

Experiment 75. A fountain.

With the apparatus Fig. 99 suck as much air as you can out of the bottle, pinch the coupling, and open it under water. Does the atmosphere lift the water into the bottle and produce a beautiful fountain?

FIG. 101
MORE MAGIC

Experiment 76. Magic tumbler.

Fill a tumbler with water, cover it with a sheet of paper, hold the paper on with your hand, invert the tumbler, and remove your hand (Fig. 100). Does the atmospheric pressure upward support the paper and water?

Experiment 77. Magic lift.

Fill a tumbler with water, press your palm down on the top with your fingers pointing downward (Fig. 101), straighten your fingers without admitting air to the tumbler, and then lift your hand. Do you lift the tumbler of water also?

There is a partial vacuum between your hand and the water, and the atmospheric pressure upward and downward holds your hand and the tumbler together.