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

Is Water Compressible?Can you change the density of

water by pushing on it?

Is Air Compressible?Can you change the density of

air by pushing on it?

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.

1 g/cm3

0.5 g/cm3

Density =

=

= 0.5 g/cm3

Volume

Mass

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

10 g

20 cm3

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

Volume Changes.

Volume Changes due to increased pressure.

Mass = 10 g Mass = 10 gVolume = 20 cm3 Volume = 5 cm3

Density = 0.5 g/cm3 Density = 2 g/cm3

Density = Mass/Volume

When volume decreases,

Density…

2 g/cm3

Is the mass of the diver changed at all?

No! Mass does not change.

Volume decreases and density increases.

2 g/cm3

1 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.

2 g/cm3

1 g/cm3

Predict

Which diver will sink first?

A B

Predict

Which diver will rise first?

A B

Mass

VolumeDensity =

Review

Review

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

Water versus Ice

Water

Question 1

2 g 10 g 20 g

Three cubes have the same volume, but very different densities. Which cube has the greatest density?

Question 2

12 g

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?

32 g 8 g

Review

Which is denser?

Both boxes have the same volume.

What is the density of the ship?

Review

Which one is more likely to float in H2O?

Both boxes have the same volume.