1. Air Pressure Inquiry Investigation 8, Part 1
Air Pressure and Wind
TG-p
Air Pressure Inquiry
Investigation 8, Part 1

2. Syringes and Pressure
Remember the activity with the syringes and tubing
Describe the investigation
The air was compressed when the plunger was squeezed
The blue foam cube became smaller because the air inside it was compressed
TG-260
Student lab Notebooks P. 45

3. Air-Pressure Inquiry Plastic jar that is tightly closed
The inside glass is half filled with water
A stopper with tubing is pushed tightly into the glass bottle
TG-260
Student lab Notebooks P. 45

4. Pressure in a Jar
What do you think will happen to the water in the tube when I squeeze the jar?
Record your predictions in your ISN.
TG-260
Student lab Notebooks P. 45

5. Gently Squeeze the Jar…
What happens to the water level in the tube?
Surprised?
Water level in tube goes down!!
Explain why this happens!
TG-261
Student lab Notebooks P. 45

6. Water molecules can not be squeezed closer together - it’s a liquid
Results
Air molecules are squeezed closer together
When you squeeze the plastic jar…
TG-261
Student lab Notebooks P. 45
Water molecules can not be squeezed closer together - it’s a liquid

7. Results
Why does the water in the tube go down when you push on the sides of the plastic jar?
When you squeeze the plastic jar…
TG-261
Student lab Notebooks P. 45

8. The volume in the plastic jar is less
Why it happens…
Increases the pressure in the plastic jar
Molecules have less room to move around so they bang into each other and the sides of the jar more often
When you squeeze the plastic jar…
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Student lab Notebooks P. 45
The volume in the plastic jar is less

9. The air inside the top of the glass bottle is also compressed
Air takes up less room
leaving an empty space in the glass bottle
Which can not change its shape
Why it happens…
When you squeeze the plastic jar…
TG-261
Student lab Notebooks P. 45
The air inside the top of the glass bottle is also compressed

10. Why it happens…
When the volume of air in the glass bottle is compressed
The water flows down the straw to fill the empty space
When you squeeze the plastic jar…
TG-261
Student lab Notebooks P. 45

11. Question 2- Page 45(LB)
Decreased the volume in plastic jar and increased air pressure
Air in the glass bottle is compressed - leaving an empty space in the glass bottle
Water flowed from the tube to fill the space previously filled with air in the glass bottle
TG-261
Student lab Notebooks P. 45

12. Question 3- Page 45 (LB) There would be less pressure
Air in the glass bottle would expand
Pushing the water up the tube
TG-261
Student lab Notebooks P. 45

13. Multimedia Gas in a syringe simulation
Compare the syringe system to the pressure indicator.
TG-262
CR-ROM -Gas in a Syringe- Matter and Energy Section

14. Density What happened to the volume?
It decreased
What happened to the number of molecules?
Stayed the same.
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15. Density
If the number of molecules stayed the same, what happened to the total mass of the molecules?
It stayed the same.
If the volume decreased and the mass stayed the same, what happened to the density of the air?
The density increased
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16. Reading
Starting on page 48 of your resource book read “What is Air Pressure”
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Student Resource Book P.48-52
TG-Teacher Answer Master- P.407

17. What Is Pressure? Atmosphere is composed of air
A column of air 1cm square has a mass of 1.2 Kg
Atmospheric Pressure: the force applied by the air above you
Molecules have mass so they are pulled to Earth by gravity
Kinetic energy helps us live with pressure
Atmospheric pressure acts with equal force in every direction

18. Barometer Measures air pressure Baro- means pressure
-meter- means measure
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Student Resource Book P.48-52
TG-Teacher Answer Master- P.407

19. Mercury Barometer
Long glass tube filled with mercury, placed in a dish of mercury
Force of air on the surface of mercury pushes the column of mercury up the tube
Although mercury is very toxic, what is the advantage?
Very accurate
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20. Aneroid Barometer How does an aneroid barometer work?
As pressure changes, a spring will coil and uncoil and give us a reading in millibars
What is the advantage?
Small and compact
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21. Units Bars Millibar (mb) Used to measure air pressure
Equal to the pressure exerted by air in the atmosphere at sea level
Millibar (mb)
Unit used to measure atmospheric pressure
1/1000 of a bar
average sea-level air pressure = 1013 mb
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22. Response Sheet-Air Pressure and Wind
Pull out page 47 of your lab book and answer the question.
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Student Lab Notebook P.47