Film title: What is a gas?
Our world is full of gases.
You can't see most of them ...
But you can see their effects.
Oxygen ...
oxygen
Helium ...
helium
And carbon dioxide, are three very common gases.
carbon dioxide
But what is a gas?
What is a gas?
A gas is simply a state of matter that's not a solid or a liquid.
state of matter
Gases are made of molecules that have lots of energy.
Molecules
They move around quickly and take the shape of their container.
If a gas is put into a larger container, it will change its shape and its molecules will spread apart to take up more space.
But the gaps between the molecules also mean that gases can be compressed or squeezed into a smaller space ...
Like in these aerosol cans.
The molecules spread apart when they are released into the air.
The ability to change the amount of space it takes up, known as its volume, is a defining feature of a gas.
gas
can change the space it takes up
known as its volume
Fizzy drinks contain gases that are dissolved and compressed in a liquid.
As soon as a can is opened, the compressed gas increases its volume and exits the can...
Making a hissing noise as it escapes!
A gas can change shape and volume.
You can't see most of them ...
But you can see their effects.
Oxygen ...
oxygen
Helium ...
helium
And carbon dioxide, are three very common gases.
carbon dioxide
But what is a gas?
What is a gas?
A gas is simply a state of matter that's not a solid or a liquid.
state of matter
Gases are made of molecules that have lots of energy.
Molecules
They move around quickly and take the shape of their container.
If a gas is put into a larger container, it will change its shape and its molecules will spread apart to take up more space.
But the gaps between the molecules also mean that gases can be compressed or squeezed into a smaller space ...
Like in these aerosol cans.
The molecules spread apart when they are released into the air.
The ability to change the amount of space it takes up, known as its volume, is a defining feature of a gas.
gas
can change the space it takes up
known as its volume
Fizzy drinks contain gases that are dissolved and compressed in a liquid.
As soon as a can is opened, the compressed gas increases its volume and exits the can...
Making a hissing noise as it escapes!
A gas can change shape and volume.
What are the properties of a gas?
Learning points
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