1. Homework Quiz
Increasing which variable would decrease the pressure of a contained gas?
Temperature b) number of particles
Boiling point d) volume
Boyle’s law relates pressure and
Temperature b) number of particles
c) Volume d) mass
The SI unit of pressure is the
a) pascal b) newton c) square meter d) psi
D, c, a

2. Equation Practice (360-style!)
Use the GUESS method to solve each of the 3 problems
You will need a calculator and your Foldable
Set up your “space” for GUESS
Partner A tells Partner B what to write (You will switch for the next problem) step by step.

3. A gas has a volume of 5. 0 L at a pressure of 50 kPa
A gas has a volume of 5.0 L at a pressure of 50 kPa. What happens to the volume when the pressure is increased to 125 kPa? The temperature does not change.

4. A gas has a volume of 5. 0 L at a pressure of 50 kPa
A gas has a volume of 5.0 L at a pressure of 50 kPa. What happens to the volume when the pressure is increased to 125 kPa? The temperature does not change.

5. Gas stored in a tank at 273 K has a pressure of 388 kPa
Gas stored in a tank at 273 K has a pressure of 388 kPa. The safe limit for the pressure is 825 kPa. At what temperature will the gas reach this pressure?

6. Gas stored in a tank at 273 K has a pressure of 388 kPa
Gas stored in a tank at 273 K has a pressure of 388 kPa. The safe limit for the pressure is 825 kPa. At what temperature will the gas reach this pressure?

7. At 10 0C, the gas in a cylinder has a volume of. 250 L
At 10 0C, the gas in a cylinder has a volume of .250 L. The gas is allowed to expand to .285 L. What must the final temperature be for the pressure to remain constant? (Hint: Convert from degrees Celsius to kelvins using the expression 0C = K.)

8. At 10 0C, the gas in a cylinder has a volume of. 250 L
At 10 0C, the gas in a cylinder has a volume of .250 L. The gas is allowed to expand to .285 L. What must the final temperature be for the pressure to remain constant? (Hint: Convert from degrees Celsius to kelvins using the expression 0C = K.)

9. Air pressure is the force put on you by the weight of air molecules.
15 # / in2
air pressure is always pushing on us from all sides - about 15 lbs/ every square inch
but at the same time our bodies push back against the air pressure with people force
so it balances out and we don't get crushed
Do water/card demo before next slide

10. Explain the teacher demo in your notes: What’s going on?
Show how much more force air pressure exerts than water. Do water tube with card demo.

11. Something like this???

12. Ear Discomfort in Higher Altitudes
When you fly in a plane (or drive up into the mountains), what happens to your ears?
Your ears pop because the air pressure is different as you go higher.  When the air inside your body changes so that it will be the same as the new pressure outside your body, your ears pop.
Do you ever get a bloated feeling when you fly?

13. Think and Explain Quiz For each demo: Magic Leaky Bottle
Write down your observations
Include a “scientific explanation” that relates the demo to what you have learned about air pressure
Magic Leaky Bottle
Collapsing Can
Egg in a Bottle