1. 1. Homework 4/2/2007 by 6 PM: Diagnoser Question Sets to review electricity and magnetism 2. Start reviewing for the exam 3. Riverside2 write up due 4/10/2007.

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6. dynamo

7. Drop the clay lump into the water. Make the clay float. Write down what you did to make the clay float. Density: Engage

8. Measure the densities of the marble and the wooden ball in grams per milliliter. Each mark on your graduated cylinder is 1 milliliter (ml). The water volume doesn’t change if you drop something into it. The water is just displaced. The average mass of the marbles is 5.2 grams and the wood ball is 2.7 grams. Why did I give you three of each? Density: Explore Density = Mass / Volume

9. The density of water is 1 gram per milliliter. What is true of objects that sink in water? What is true of objects that float in water? What is the general principle?  If the density of an object is greater than the fluid it is immersed in, it will sink. Otherwise it will float.  Archimedes: The upward buoyant force on an object is equal to the volume of the fluid displaced. Density: Explain

10. Real sphere of marble Buoyant Force = Weight of fluid displaced Gravity Force = Weight of fluid displaced Imaginary sphere of fluid

11. Often air and water can both be treated as fluids. Pressure is Force per Area Areas of high pressure push things towards areas of low pressure. Atmospheric pressure decreases with altitude and water pressure increases with depth. Density: Extend

12. The same force applied over a smaller area results in greater pressure – think of poking a balloon with your finger and then with a needle.

13. Gas molecules behave a lot like colliding billiard balls. Molecules in a hotter gas move faster, all else being equal. Increasing the temperature of a gas while keeping volume and the number of molecules constant increases the pressure. Increasing the number of molecules in a gas while keeping volume and temperature constant increases the pressure. Density: Extend

15. Demonstrate the Cartesian diver made from a soy sauce packet in water. You may or may not have to add a paper clip like I did. Write down your observations. Pass around the diver. Discuss an explanation with your groups. Density: Evaluate