1. Year 8 Pressure in fluids

2. Air pressure and hydrostatic pressure
Learning objectives
Explain the effects of air pressure
State the relationship between depth and hydrostatic pressure
Explain the design of dams

3. Magdeberg spheres

4. Magdeburg spheres Draw the diagram above Describe what you did
Explain your observations

5. Hydrostatic Pressure

6. Hydrostatic Pressure
What will happen when the fingers are removed from the holes in the tank of water?
Give as much detail as possible.

7. Hydrostatic Pressure
How do you explain this?

8. Hydrostatic Pressure
The deepest open circuit scuba dive was accomplished by Pascal Bernabé. The reading on his pressure meter was kPa. What depth did he reach?

9. Dams Why is the dam wall thicker at its base?
The dam wall is 10m deep from the water level. The reservoir contains freshwater.
Each arrow shows the pressure at metre intervals.
Calculate the pressure at each metre interval.
Plot a graph showing the relationship between depth and pressure.
State the relationship between depth and pressure.
A fish is swimming at a depth of 4.6 metres. Use your graph to determine the hydrostatic pressure exerted on the fish.

10. Air Pressure
Air pressure is approximately 100kPa at sea level but it varies plus or minus 5% due to the weather.
Warming air in a container causes an increase in pressure.
Cooling air causes a decrease in pressure.
This is because of changes to the kinetic energy of the air molecules.

11. Air Pressure
A pen cap floats in a plastic lemonade bottle three-quarters full of water. If you squeeze the bottle the pen cap sinks to the bottom. If you then let go of the bottle, the pen cap floats to the surface.

12. (a) When the bottle is squeezed what, if anything, happens to: (i) the distance between the air molecules inside the bottle? mark (ii) the distance between the water molecules inside the bottle? (iii) the pressure of the air trapped inside the pen cap? (iv) the volume of the air trapped inside the pen cap? (b) Explain why the pen cap sinks when you squeeze the bottle marks

13. Learning objectives
State the relationship between height (and depth) and the pressure in fluids
Explain the relationship between height and pressure
Outline the use of manometers in measuring the pressure in fluids

14. Task 1
Complete the worksheet to recap some ideas about fluids

15. Pressure in fluids atmospheric pressure noun
the pressure exerted by the weight of the atmosphere, which at sea level has a mean value of 101,325 pascals

16. Task 1
Complete the worksheet “A question of Pressure”

17. Manometers