22
The power of air
and water
You will need
– G2 hydraulic cylinder
– Cup of water
Here’s how
1. Pull the piston of the G2 cylinder outward
and then seal the opening of the tube
connection nozzle with your finger.
2. Now push the piston in. It will slide in
about a centimeter or two, but will spring
back when released.
3. Now, fill the G2 cylinder completely with
water. To do this, dip the opening of the
tube connection nozzle into a cup filled
with water, push the piston all the way in,
and then pull it out again.
4. Again, seal the opening of the tube
connection nozzle with your finger and
push the piston in. You will hardly be able
to move it in at all, and you will not feel
the same springy, elastic feeling you felt
when the cylinder was filled with air.
1
3
4
EXPERIMENT
1
–
Air is elastic. Air-filled balls used in sports take advantage of this
scientific fact. The elastic air in bicycle and car tires absorbs vibrations
and shocks while the vehicles are moving.
Unlike air, water can hardly be squeezed. This applies generally to all
liquids, including oil. Under the influence of pressure, the density of all
real substances changes, but especially with gases. This is much less the
case with liquids and solids than with air. The amount by which a
substance can be compressed is referred to as its
compressibility.
Cup of
water
W
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A
t’s
h
a
p
p
en
in
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