1. STATES OF MATTER

2. GAS PRESSURE

3. Learning Points
Predict the effect of gas pressure using the particulate theory.

4. GAS PRESSURE
In the compression experiments you had a cap or your finger over the end of the syringe containing a gas, Air.
Air is actually a mixture of gases.
When you squeezed the syringe you were increasing the AIR PRESSUE in the syringe.

5. Air pressure is equal in all directions.
GAS PRESSURE
Air pressure is equal in all directions.
Air pressure is caused by the force of air gas particles bumping into things.

6. Click here for gas pressure animation

7. Can you think of any examples when air pressure is increased?
Balloons
Air is forced into a balloon under pressure. As the number of air particles and collisions increase, the pressure inside the balloon increases.

8. QUICK EXPERIMENT INSTRUCTIONS
AIM: To find out how many breathes it
takes to burst a balloon.
INSTRUCTIONS
Count how many breathes is needed for you to burst your balloon

9. HOW STRONG IS GAS PRESSURE?
Part 1: Collapsing can
Your teacher is going to demonstrate how powerful gas/air pressure is.

10. Collapsing can
Your teacher is going to try and collapse a metal can by changing the air pressure in the inside of the can by sucking out air using a pump.

11. WHAT HAPPENED?
CAN YOU EXPLAIN WHY?

12. EXPLANATION
The pump sucks out any air/gas particles from inside the can.
Therefore, the only air particles that are hitting the can are on the outside.
There are no gas/air particles inside the can to push against the force of the particles pushing from the outside.
The can collapses.

13. AIM: To collapse a can using air pressure.
QUICK EXPERIMENT
AIM: To collapse a can using air pressure.

14. Click here to watch a collapsing
INSTRUCTIONS
Watch the following video and see if you can do the same thing and collapse an aluminum can.
Click here to watch a collapsing
can video

15. HOW STRONG IS GAS PRESSURE?
Part 2: Magdeburg
Hemispheres
Your teacher is going to demonstrate how powerful gas/air pressure is.

16. Magdeburg Hemispheres

17. WHAT HAPPENED?
CAN YOU EXPLAIN WHY?

18. EXPLANATION
The pump sucks out any air/gas particles from inside the two hemispheres.
Therefore, the only air particles that are hitting the hemispheres are on the outside, keeping the hemispheres together.

19. MAGDEBURG HEMISPHERES
In the original experiment two brass hemispheres were brought together and the air inside removed by a pump.
The hemispheres were held together by the pressure of the gas particles in the atmosphere pushing against the outside of the hemispheres.

20. USING AIR PRESSURE TO HOLD ON
reuters.com
up-ship.com
cbsnews.com