Transcript Aim – Why do things float or Sink?
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?