2. Properties of Gases The volume of a gas is the same as the volume of its container.

3. Properties of Gases The volume of a gas is the same as the volume of its container. This is because gases fill the space available.

4. Measuring gas temperature Temperature is a measure of the energy of motion of the particles.

5. Measuring gas temperature Temperature is a measure of the energy of motion of the particles. The faster the particles move, the greater the energy and higher the temperature.

6. A thermometer is like a speedometer for molecules.

7. How fast do gas particles travel?

8. About 500 meters/second at room temperature.

9. How fast do gas particles travel? About 500 meters/second at room temperature. They collide constantly with each other and the walls of their container.

10. The outward push is called pressure.

11. Pressure = Force/Area

12. The outward push is called pressure. Pressure = Force/Area The USA measures pressure as PSI

13. The outward push is called pressure. Pressure = Force/Area The USA measures pressure as PSI (pounds per square inch).

14. The outward push is called pressure. Pressure = Force/Area The USA measures pressure as PSI (pounds per square inch). The SI measure is kPa (kilopascals).

15. In an inflated ball, there are more particles inside than outside.

16. In an inflated ball, there are more particles inside than outside, so the pressure inside is greater.

17. Your chance for fame & fortune! If you increased the pressure on the outside of the ball, would the ball change in volume?

18. If you said the ball would get smaller...

19. You could have been famous! the ball would get smaller... If you said

20. Boyle’s Law When the gas pressure increases, the volume decreases. When the pressure decreases, the volume increases. This is called

21. Boyle’s Law Least pressureMost pressure Most volumeLeast volume

22. A second chance at fame.. If you put a balloon in the refrigerator, would it stay the same size, increase in size, or decrease in size?

23. And the answer is... It would decrease in size?

24. Charles’s Law When the temperature of a gas is increased, its volume increases. When the temperature decreases, volume decreases. This is called

25. Charles’s Law Low temperatureHigh temperature Low volumeHigh volume

26. Charles’s Law Low temperatureHigh temperature Low volumeHigh volume If you double the temperature, you also double the volume.

27. Relationship between pressure and temperature. Low temperature (slow particle movement) High temperature (fast particle movement) Low pressureHigh pressure

28. Which box below would have the least mass, A or B? Low temperature A High temperature B Low pressureHigh pressure

29. The answer is NEITHER. The mass would be the same! WHY? Low temperature A High temperature B Low pressureHigh pressure

30. The amount of matter is unchanged. Low temperature A High temperature B Low pressureHigh pressure

31. But I’ve always heard that hot air rises, so wouldn’t B be lighter? Low temperature A High temperature B Low pressureHigh pressure

32. It would be more accurate to say that less dense air rises. Low temperature A High temperature B Low pressureHigh pressure

33. And the density of A and B is the same. Low temperature A High temperature B Low pressureHigh pressure

34. So how could you make box B gas less dense than A? Low temperature A High temperature B Low pressureHigh pressure

35. When you figure that out, you’ll know the real secret behind why a hot air balloon floats! Low temperatureHigh temperature Low pressureHigh pressure