1. Thursday, November 17
Is ice more dense or less dense than liquid water? Give evidence to support your answer.

4. Cartesian Divers
The Cartesian diver is named after French philosopher and scientist René Descartes
CARTESIAN

6. Think of a deflated floaty vs inflated floaty.
DEFLATED FLOATY:SINKS
INFLATED FLOATY:FLOATS

7. How does it work?
The diver contains an air bubble sealed inside. The combined density of the pipet, air and weight is slightly lower than that of the water, so it floats. When you squeeze the sides of the bottle you increase the pressure pushing on the air bubble, making it compress into a smaller space. This decrease in volume causes the air bubble to increase in density. Therefore the overall density of the diver will now be greater than that of the surrounding water, making it sink. Releasing the pressure (by stopping squeezing the bottle) allows the air bubble to expand back to it's normal size, and so the diver will float again.

8. Cartesian Worksheet: Required (44 points) To earn optional EXTRA CREDIT (up to 25 points) 1. Try to make a cartesian diver, but not successfully=10 points 2. Successfully make a working diver=15 points 3. Design a fancy, decorated working diver=20 points 4. Present and briefly explain your fancy diver to the class on Tuesday, 11-21=25 points

9. Thursday, November 17
What happens to the molecules of a substance during a physical change? During a chemical change?

10. During a physical change, the molecules remain the same.

11. Dissolving sugar in warm water is a physical change.
Before dissolved in water
After dissolved in water

12. During a chemical change, the molecules rearrange and form new stuff.
Sodium acetate
carbonate