1. What is air?

2. Recall syringe
What happened when you mixed citric acid and sodium bicarbonate?
It produced a gas
What could that gas be?
What could the gas be made of?

3. List gases you have heard of
Make a list with group LM p 24 #1

4. Define gas
In your own words LM p 24 #2
Gas:….

5. Gas
Physics . a substance possessing perfect molecular mobility and the property of indefinite expansion, as opposed to a solid or liquid.
A state of matter with no definite shape or volume

6. What elements could be in the gas that forms when sodium bicarbonate and citric acid react? LM p 24 #3
Carbon ( C )
Hydrogen (H2)
Oxygen (O2)
Sodium (Na)

7. Possible gases H2 or hydrogen O2 or oxygen CO2 or carbon dioxide
H2O or water vapor

8. What gases could be produced when you sodium bicarbonate and citric acid react?
LM page 24 #4

9. Gas produced
When you add sodium bicarbonate and citric acid the gas produced is carbon dioxide
NaHCO3 + C6H8O7  CO2 + H2O+Na3C6H5O7

10. What is air? In the atmosphere We breath it
Mixture of gases (learned in 7th grade)
Is matter

11. How can we prove air is matter?
How can we find out if the air in the ball has mass?
Demo with ball
What caused the mass of the ball system to change?
Does air take up space in the ball?
How do you know?

12. Is air matter?
We know because the ball weighed less before we added air then it did after we added air.
The air caused the ball to increase in mass so the air must have mass
The ball is more full, or firmer, so the air takes up space
If air has mass and takes up space then it is matter

13. Let’s explore Using a syringe system Syringe, tubing, binder clip
May work with air or without air

14. Explore Rules Do not use the syringe systems to annoy anyone
You can use the clip
Work with partners

15. To remove the tube Use fork and pry gently
DO NOT POKE OTHERS WITH FORK

16. Try this Put the tube on the syringe Pull out the plunger a little
Bend the tube
Put on the clip
Take turns practice pushing and pulling the plunger
Make a note about your observations

17. Now Connect 2 syringes with the tube
Push and pull and see what happens
Note observations

18. Transparency 6
Answer questions in notebook LMp 25

19. Vocabulary Air is a mixture of gases.
Air is matter. It has mass and takes up space.
Compressed air: air that is forced into a smaller space
Expanded air: to occupy more space, when the force holding air in a smaller space is removed the matter occupies more space.

20. Air Composed of tiny particles too small to see
Particles are constantly moving and have space between them
They bounce off of one another and the sides of their container all the time

21. Imagine you can see the particles inside the syringe
Explain what you think is happening to the air particles as you compress and expand the air inside the syringe.

22. Plastic bubbles I have cut bubbles from a sheet. DO NOT POP THEM!
Put the bubble into the syringe
Insert the plunger half way
Clamp the tubing to make a closed system

23. Plastic bubble continued
Think about what is happening to the syringe, the air inside the syringe and the air bubble as you apply force.
Push and pull and observe
Make notes of your observations
Talk to your partners.
Come up with an explanation for what you observe that includes what is happening to the air particles

24. Discussion What is inside the syringe? What is in the bubble?
What happens to the air in the syringe when you push down on the plunger?
What happens to the bubble when you push on the plunger?

25. Discussion continued Why does the bubble shrivel?
What happens to the bubble when you pull up on the plunger?

26. Air as particles Lab Manual page 25
Work as a group and write short precise answers to the seven questions
7 minutes

27. LM page 25
What is the air in the syringe and the air in the bubble made of?
*Air particles

28. What happens to the air particles in the syringe when you push on the plunger?
*The air particles are pushed closer together

29. What happens to the air particles in the bubble when you pull up on the plunger?
*They get farther apart

30. Are there more air particles in the bubble when it is compressed or when it is expanded?
*Always the same number. The bubble is sealed. No particles can go in or out.

31. When you push on the plunger, are the air particles closer together in the syringe or in the bubble?
*The average distance between particles is the same in the syringe and in the bubble

32. What is between air particles?
Nothing- only space or distance, but no matter.

33. What happens to air particles when a volume of air is compressed?
*Particles are closer together.

34. When a volume of air expands?
*Particles are farther apart.

35. Air in a Syringe Lab Manual pages 26-27
Read along silently as I read aloud
10 minutes to complete page and complete drawings
Turn in
Homework/Class work: Read “Particles” page Resource Book
Complete questions LM page 29

36. Key Points Air is matter. It has mass and takes up space.
Compressed air: air that is forced into a smaller space
Expands: to occupy more space, when the force holding air in a smaller space is removed the matter occupies more space.
There is nothing between particles of gas-only space
During compression and expansion the number and size of particles in a sample of gas do not change. Only the space between the particles.

37. particle
Smallest piece of any substance that is still that substance

38. Diagram of a water particle