Cartesian Divers!

List 5 facts or observations! Cartesian Divers! How do they work? List 5 facts or observations! Sketch a diagram

When is it easier to make the divers sink? When the bottle has very little air in it. When the bottle is half-full of air. A B

Can you change the density of water by pushing on it? Is Water Compressible? Can you change the density of water by pushing on it?

Can you change the density of air by pushing on it? Is Air Compressible? Can you change the density of air by pushing on it?

No. Only air is compressible. The density of air can change. Is Water Compressible? No. Only air is compressible. The density of air can change.

Using density, explain why the diver floats. Water’s density = 1 g/cm3. The diver’s density is less than 1 g/cm3. 0.5 g/cm3 1 g/cm3

Density = = = 0.5 g/cm3 10 g 20 cm3 As compared to water, 0.5 g/cm3 is less dense than water. It floats.

What changes when you squeeze the bottle? (Don’t say color.) Volume Changes.

Volume Changes due to increased pressure.

Density = Mass/Volume Mass = 10 g Volume = 20 cm3 Volume = 5 cm3 Density = 0.5 g/cm3 Density = 2 g/cm3

When volume decreases, Density… 2 g/cm3 Increases!

Is the mass of the diver changed at all? No! Mass does not change. Volume decreases and density increases. 1 g/cm3 2 g/cm3

Using density, explain why the diver sinks. Water’s density = 1 g/cm3. The diver’s density is greater than 1 g/cm3. 1 g/cm3 2 g/cm3

Which diver will sink first? Predict Which diver will sink first? A B

Which diver will rise first? Predict Which diver will rise first? A B

Review Mass Volume Density =

1. Why does a cube of ice float in water? Review 1. Why does a cube of ice float in water?

Water versus Ice Water

Question 1 Three cubes have the same volume, but very different densities. Which cube has the greatest density? 2 g 10 g 20 g

Question 2 Three cylinders have the same volume, but very different densities. Which cylinder will displace the most water when submerged? Or will each cylinder displace the same volume of water? Same 8 g 12 g 32 g

Review Which is denser? Both boxes have the same volume.

What is the density of the ship? 0.9 g/cm3

Which one is more likely to float in H2O? Review Which one is more likely to float in H2O? Both boxes have the same volume.