Understanding

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Understanding Gases
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Gases

• fill balloons
• propel bullets
• form the Earths atmosphere
• are invisible
• have the ability to expand and contract
• are made of atoms or molecules

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What Do Gases Look Like?
If we could magnify gas atoms and molecules a
hundred million times they would look something
like the wildly flying Ping- Pong balls of state
lottery games.
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What happens when you heat gas molecules?
Lets try this experiment and find out.
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What is inside of this bottle?
PREDICT What will happen to the balloon if the
bottle is placed in hot water?
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What do you see happening to the balloon?
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What is making the balloon expand?What is
happening to the molecules inside the bottle?
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What would happen if the air inside the bottle
was cooled?
Lets replace the hot water with ice and find
out!
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What is happening to the balloon now?
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And now?
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And now?
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What is causing the balloon to collapse?What is
happening to the molecules inside the bottle?
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The Science Behind it All
Heating gas causes molecules to
Speed up
They actually move so fast that they collide with
each other with great force. This increases the
pressure inside the bottle causing the balloon to
expand in response to the increased pressure
inside the bottle.
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Cooling the gas inside the bottle causes the
molecules to
Slow down
They move very slowly and contact each other with
much less force. The molecule pack in closer
together.