2. BELLRINGER YOU HAVE 7 MINUTES LEFT! 1. What would be the density of a 9.0g sample of a substance that has a volume of 89 mL? Will this substance sink or swim? 2. What is the mass of a toy truck that has a volume of 23 mL and a density of 7.3 g/mL? USE WE IPC PLEASE!!!!!!!

3. BELLRINGER YOU HAVE 6 MINUTES LEFT! 1. What would be the density of a 9.0g sample of a substance that has a volume of 89 mL? Will this substance sink or swim? 2. What is the mass of a toy truck that has a volume of 23 mL and a density of 7.3 g/mL? USE WE IPC PLEASE!!!!!!!

4. BELLRINGER YOU HAVE 5 MINUTES LEFT! 1. What would be the density of a 9.0g sample of a substance that has a volume of 89 mL? Will this substance sink or swim? 2. What is the mass of a toy truck that has a volume of 23 mL and a density of 7.3 g/mL? USE WE IPC PLEASE!!!!!!!

5. BELLRINGER YOU HAVE 5 MINUTES LEFT! 1. What would be the density of a 9.0g sample of a substance that has a volume of 89 mL? Will this substance sink or swim? 2. What is the mass of a toy truck that has a volume of 23 mL and a density of 7.3 g/mL? USE WE IPC PLEASE!!!!!!!

6. BELLRINGER YOU HAVE 3 MINUTES LEFT! 1. What would be the density of a 9.0g sample of a substance that has a volume of 89 mL? Will this substance sink or swim? 2. What is the mass of a toy truck that has a volume of 23 mL and a density of 7.3 g/mL? USE WE IPC PLEASE!!!!!!!

7. BELLRINGER YOU HAVE 2 MINUTES LEFT! 1. What would be the density of a 9.0g sample of a substance that has a volume of 89 mL? Will this substance sink or swim? 2. What is the mass of a toy truck that has a volume of 23 mL and a density of 7.3 g/mL? USE WE IPC PLEASE!!!!!!!

8. BELLRINGER YOU HAVE 1 MINUTE LEFT! 1. What would be the density of a 9.0g sample of a substance that has a volume of 89 mL? Will this substance sink or swim? 2. What is the mass of a toy truck that has a volume of 23 mL and a density of 7.3 g/mL? USE WE IPC PLEASE!!!!!!!

9. Buoyancy & Pressure Properties of Matter

10. 1.What is buoyancy? Buoyancy - measure of the upward pressure (force) a fluid exerts on an object.

11. 2. Archimedes’ Principle The force exerted on an object is equal to the weight of the fluid displaced by the object. The metric unit for force or weight is newtons (N).

12. 3. Do all fluids exert the same buoyant force on an object? No…it depends on the weight of the displaced fluid.

13. 4. Why objects sink? An object sinks when the buoyant force is less than its weight.

14. If the buoyant force is greater than the object’s weight, it will float. 4. Why objects float?

15. 5. What is Neutral buoyancy… When the buoyant force is equal to the weight of the object. Example: Divers use neutral buoyancy to swim at a steady level underwater.

16. Why does a steel block sink and a boat float? 12 3

17. 6. Which state is buoyancy also a property of? Buoyancy is also a property of gases. Example: Balloons (hot air, helium, etc.) will float when the volume of air displaced weighs more than the balloon, gondola, and rider(s) combined.

19. 7. Charles’ law: The volume of a gas increases with increasing temperature and volume decreases with decreasing temperature. When pressure remains constant, then…

20. Click to see animated version: http://www.grc.nasa.gov/WWW/K-12/airplane/aglussac.htmlhttp://www.grc.nasa.gov/WWW/K-12/airplane/aglussac.html

21. Gases and Pressure 8. Pressure - the force acting on a unit area of surface. 9. Gas pressure is caused by collisions of gas particles with the walls of its container. The more collisions, the greater the pressure.

22. The unit for pressure in the metric (SI) system is the pascal (Pa). 10. A pascal is equal to one newton of force acting on one square meter of surface area.

23. 11. What is atmospheric pressure? Each particle of air held in place by gravity collides with and exerts a force against you and everything around you, creating air pressure.

24. At the Earth’s surface, the air’s pressure is 101,300 pascals (~weight of an elephant!) Why don’t we collapse?

25. 12. What is the relationship between altitude and pressure? Higher altitude means less gravity and less atmospheric pressure. Does this explain why your ears pop when you fly?

26. Other common units for atmospheric pressure:

27. 13. Boyle’s law: Gas pressure increases with decreasing volume. Gas pressure decreases with increasing volume.

28. Click to see animated version: http://www.grc.nasa.gov/WWW/K-12/airplane/aboyle.htmlhttp://www.grc.nasa.gov/WWW/K-12/airplane/aboyle.html

29. 14. Boyle’s law equation: When temperature remains constant, then

30. Practice!! Suppose 5 liters of air at atmospheric pressure (101.3 kilopascals) is compressed into a 0.5 liter aerosol can. What is the pressure of the compressed air in the can?

31. Answer!! Suppose 5 liters of air at atmospheric pressure (101.3 kilopascals) is compressed into a 0.5 liter aerosol can. What is the pressure of the compressed air in the can? P1V1 = P2V2 (101.3 kPa) (5.0L) = (P2) (0.5L) 506.5 = (P2) (0.5) (0.5) 1,013 kPa = P2

32. Mythbusters Watch this video and write down 5 things you learned from the video. http://dsc.discovery.com/videos/myt hbusters-lets-talk-buoyancy.html http://dsc.discovery.com/videos/myt hbusters-lets-talk-buoyancy.html

33. Summary Write 5 things you have learned from the notes today. Go to explorelearning.com Do the Archimedes’ Principle gizmo and answer the assessment questions.