What is the volume of a cylinder that has a radius of 3 cm and a height of 10 cm?

Volume = πr 2 x h 3cm x 3cm = 9cm 2 V= 3.14x (3cm x 3cm) x10cm V= 282.6 cm 3 9.0cm

2 X 3.14

28.26 cm 2 x 10 cm 282.6cm

3 r= 3cm h= 10cm

Aim – Why do things float or Sink?

Buoyancy

• Buoyancy is the force in a liquid or gas that pushes upwards. The opposite of gravity!

Buoyancy Gravity A Nun Buoy

Matter can have

• Positive buoyancy - it floats • Negative buoyancy – it sinks • Neutral buoyancy – it “Flinks”

• Positive Buoyancy • The force of buoyancy is greater than the force of gravity!

• Negative Buoyancy • The force of gravity is greater than the force of buoyancy!

Neutral Buoyancy • The force of gravity is equal to the force of buoyancy!

Fluids with Different Densities (fluids include liquids and gases) 1.0 g/cm 3 13.5 g/cm 3 0.00018 g/cm 3

Sink or float in Water (1.0 g/cm

3

)?

1. Silver……………………….10.40 g/cm 3 2. Douglass fir……………….0.56 g/cm 3

3. Submarine ………………. 1.0 g/cm 3

Sink or float in Water ?

1. Salt………………………….2.200 g/cm 3 2. Maple………………………0.69 g/cm 3 3. Ebony……………………..1.20 g/cm 3 4. ZBT ………………………….1.00000009 g/cm 3 5. XBT …………………………0.99999999 g/cm 3

Sink or float in Gasoline (0.72 g/cm

3 )?

6. Balsa………………………0.12 g/cm 3 7. Maple………………………0.69 g/cm 3 8. Ebony……………………..1.20 g/cm 3 9. White Pine…………………0.43 g/cm 3 10. ABT …………………………0.72 g/cm 3

• A sphere has a volume of 38.2 cm3. If it flinks in water, what is its mass?