5.4
Explaining gas pressure
Explaining gas pressure
Raj blows up a balloon. The balloon gets bigger and bigger. Why?
Objectives
■
Explain what causes
gas pressure
■
Explain air pressure and its
effect on boiling point
■
Explain how temperature
affects gas pressure
When Raj starts blowing, air particles enter the balloon. The particles move
quickly in all directions. They bump into, or collide with, the rubber. The
colliding particles exert a force on the rubber, and push it outwards. The force
per unit area is called pressure.
As Raj continues blowing, more air particles enter the balloon. The balloon
gets bigger.
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The more Raj blows into the balloon, the greater the
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of air &particles
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How does temperature affect gas pressure?
ng
Raj ties up his balloon. He leaves it in a warm room. The balloon gets even
bigger. Why?
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te
In
The air particles inside the balloon warm up. They move faster. They hit each
other, and the sides of the container, more often. The air pressure inside the
balloon has increased. In the warm balloon, the faster moving particles are
further apart. This is why the balloon gets bigger.
at
Saniyah puts a plastic bottle in a freezer. The air in the bottle cools down. The
particles move more slowly. They hit each other, and the inside of the bottle,
less often. The pressure inside the bottle has decreased. The bottle collapses.
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c.
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The bottle collapses as the air pressure inside
it decreases.
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