This document discusses gases and how they differ from other forms of matter. It notes that air is made up of gases, which are invisible and spread out to fill any container. The document also discusses how heating and cooling can change the state of matter, using water as an example to show how it changes from liquid to solid ice and back again. Finally, it defines steam as the gas that water becomes when it boils and rises into the air as vapor.

1. 1st Grade
What Can We Observe About
Gases?

2. Observing Gases
 Air is made out of gases.
 A gas is a kind of matter. Where is the air
in each picture?
 You can not see most gases.

3. -A gas is matter that does not have its own
shape.
-It spreads out to fill its container.
-It takes that shape of the container.

4. Heating and Cooling Matter
 Heating and cooling can change matter.
 You can see how matter changes by observing
water.
Stream in summer Stream in winter
In summer, the water in this stream is warm. Being In winter, the water in the stream gets cold. When
warm keeps the water liquid. the water gets cold enough, it changes into ice. Ice
is solid water
In spring, the water will get warm again. It will change back to a liquid.

5. What is steam?
 When water boils, it becomes a gas.
 This gas is called steam.
When the water gets hot enough,
it becomes steam.
The steam goes into the air.
As steam cools,
it forms tiny drops of water that
make a little cloud.

6. Put on your thinking caps!
 What is gas?
 What is steam?
 Think about how and
why matter may
change.
 What would happen if
you blew air into a bag?
Why?
 What changes water
from liquid to a solid?