Page 75 - Active Science 5 Ebook and Activity

2. Air occupies space.
Activity 6.3

Aim : To prove that air occupies space.

Materials Required : An empty glass, water in a tub

Procedure : • Take an empty glass.

• Turn the glass upside down and place
it on the surface of water in a tub.

• Gently press it down.

Observation : You will see that water does not enter

the glass. Water cannot enter the glass as it is full of air.

Conclusion : This shows that air occupies space.

3. Air exerts pressure.

Air takes up space and has weight. Anything that has weight exerts pressure. Air exerts
pressure in all directions. This pressure is known as air pressure.

Activity 6.4

Aim : To prove that air exerts pressure.

Materials Required: Capped plastic bottle filled with water, a pin

Procedure : • Take a capped plastic bottle filled with water.

• Take a pin and poke a hole into the side of the bottle close to the
bottom.

• Remove the pin.

Observation : At the hole of the bottle, two forces are at
work. Water pressure inside the bottle is
trying to push the water out of the pinhole.
At the same time, the air pressure outside

the bottle is trying to keep the water inside
the bottle. When the bottle is capped, the forces inside and outside the
bottle remain equal and water does not leak out of the pinhole. But
when the cap is removed, the air pressure above the water becomes

greater and forces the water out of the pinhole.

Conclusion : The experiment shows that air exerts pressure.

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