1. Air Pressure and Gravity Unit
Lesson 3 - All About Air Pressure

2. Objective
We will be able to use observations, questioning, and reasoning to discuss science.
We will understand the meaning of air pressure and compression.
Objective 1
Generating Evidence: Using the processes of scientific investigation (i.e. framing questions, designing investigations, conducting investigations, collecting data, drawing conclusions)
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Framing questions: Observe using senses, create a hypothesis, and focus a question that can lead to an investigation.
Designing investigations: Consider reasons that support ideas, identify ways to gather information that could test ideas, design fair tests, share designs with peers for input and refinement.
Conducting investigations: Observe, manipulate, measure, describe.
Collecting data: Deciding what data to collect and how to organize, record, and manipulate the data.
Drawing conclusions: Analyzing data, making conclusions connected to the data or the evidence gathered, identifying limitations or conclusions, identifying future questions to investigate.

3. Vocabulary Words
air- The mixture of gases, which form the atmosphere of the Earth
air pressure – the force of air pressing on a surface
compress – to reduce the size or volume by pressing or squeezing it

4. All About Air Pressure
How do these balloons show that air takes up space?
What would happen if the boy lets go of the balloon?
Look straight at you. Can you see air?
But does that mean air is not there?
more air fills up the balloon on the left and makes it bigger than the balloon on the right.
the air would come rushing out no

5. All About Air Pressure
Look at the boy’s balloon. There is only a little air in the balloon.
Look at this picture. The balloon is big and round. Air takes up the space inside the balloon.

6. Compressing Air
You know that air takes up space but what happens when the air it takes up gets smaller?
When things get squeezed into a smaller space, they get compressed.
You can inflate a balloon to show kids that the air has nowhere to go.
To compress something means to reduce the size or volume by squeezing it.

7. The Force of Air What is happening to the air inside the balloon?
As air gets compressed, it pushed harder and harder against the insides of the balloon.
You can inflate a balloon to show kids that the air has nowhere to go.
The harder we squeeze the more the air inside is being compressed.

8. Experiment
Today you will see how much air pressure and compression a balloon can take.
Materials:
1 balloon per student
1 student per balloon
1 foot per student
air

9. Experiment Direction: Inflate the balloon and tie the end closed.
Place the inflated balloon on the ground.
Step / compress on the balloon gently with one foot.
What are you doing to the balloon?
Is the air pressure increasing inside?
Where is the air going?

10. Experiment
Did the compress the balloon to much?
Was the air pressure to high in the balloon that it popped?
Now, gently place the other foot on the balloon. You should have 2 feet on the balloon.
If not, continue to compress and increase the air pressure.

11. Experiment Why did some kids’ balloon pop faster than others?
Discuss it with a partner
That’s right! Some balloons had less space to expand. The air had nowhere to go. So, it made room by popping!

12. Show What you know What did we learn about air? How can we use air?
What does compress mean?