EXTENSION Provide students with small tubing, like that used in aquariums. Can they siphon out the oil?

HUH? The oil floats on the water because it is less dense.

More water and density - Properities of Salt Water

MATERIALS: two tall glasses of water, tablespoon, salt, two eggs

1. Fill one glass with water

2. Stir 5 tablespoons of salt into one glass of water

3. Add one egg to each glass

4. What happens to the eggs?

HUH? When you add salt water density increases. This makes it denser than the egg.

Ice Melts - Polar Oceans

MATERIALS: 2 bowls, plate, 3 shallow pans, salt, spoon, water, timer, five ice cubes

1. Place one ice cube in a bowl of cold water

2. Place another ice cube in a bowl of hot water

3. Place the third ice cube on a plate

4. Use a timer to see how long each takes to melt.

5. HUH? Water conducts heat better than air. So the ice cube in the warm water melts the faster than the ice cube on the plate

Place a fourth ice cube on a plate. Sprinkle with salt. What happens?

HUH? Ice and salt mix, temperature cools, and speeds up the melting process.

Place the last ice cube on the plate, press with the spoon handle. What happens?

HUH? Ice melts when it is pressed, that's why it is slippery to walk on. As your feet press on the ice it melts and a layer of water under your feet makes you lose your grip.