1. Pressure
Pressure: amount of force per unit of area (pressure = force ÷ area) Can change pressure by changing either the force or the area Which exerts more pressure, a pencil point or an eraser? Why?

2. What are some examples of pressure?

3. What is the best way to pull out someone from an icy pond?
pressure
What is the best way to pull out someone from an icy pond?

4. Remember air molecules are in constant motion
Air Pressure
Remember air molecules are in constant motion
These moving molecules create air pressure
Most air is close to Earth’s surface, so that is where the air pressure is greatest
Less air pressure as altitude increases
Air pressure is measured with a barometer

6. Bernoulli’s Principle: moving air exerts less pressure than still air
Air pressure
Bernoulli’s Principle: moving air exerts less pressure than still air
Take a piece of paper and blow across it: what happens?
The paper rises because the air pressure above it has decreased; pressure is higher below which pushes it up

7. Air Pressure
Airplane wings take advantage of Bernoulli’s Principle to increase lift

9. Remember water molecules are more closely packed than air molecules
Water pressure
Remember water molecules are more closely packed than air molecules
Water exerts pressure because of the weight and movement of the molecules
Water pressure changes with depth
more depth, more pressure
Blobfish

10. Why are water tanks tall?
Water pressure
Why are water tanks tall?
Water tanks are elevated so that gravity creates water pressure to push the water to homes and businesses
Fluids can transfer pressure: if you apply pressure to one part of the liquid, the pressure travels throughout it
Hydraulics take advantage of this

12. Buoyancy is the ability to float
Water and other fluids exert an upwards force (buoyant force)
Acts opposite to gravity
Fluid pressure is exerted in all directions and increases with depth
Remember submerged objects displace their own volume (Archimedes’ principle)
Something floats as long as the buoyant force is equal to its weight

13. “Under Pressure” performed by Kermits