1. Launch

2. Learning objectives Be able to describe how forces can be transmitted through a liquid Be able to explain how hydraulic systems can be used as a force multiplier Understand how pressure, force and area are related

3. The SupaCat weighs 32 tonnes, as much as 6 elephants! How can such a heavy machine drive over soft sand so easily?

4. Investigate how force, area and pressure are connected. Use the 5 different sized faces of the wooden block to change the area pushing on the sand. Apply the same mass (2kg) each time and measure the depth of impression created in the sand. Calculate the pressure generated by each area. Pressure (N/cm 2 ) = Force (N) Area (cm 2 )

5. The SupaCat also uses hydraulics – a principle that uses the relationship between pressure and surface area to multiply force.

6. Area = 1m 2 Input force = 10N What pressure is generated? What happens to all the particles? What happens to the pressure? Area = 0.5m 2 What force is generated? Force multiplier

7. Investigate how hydraulic systems could be used as a force multiplier by carrying out the experiment on worksheet 2.

8. Where do you think the force multiplier principle is used on the SupaCat?

9. The Shannon lifeboat uses a jet propulsion system, showing how hydraulics can be used to propel objects. The Shannon’s engine generates 32kN of force by pushing 750 litres of water per second out of two jets.

10. The Shannon class lifeboat engines are capable of generating 1300hp. This propels it to rescues at 25 knots (28 mph). Each Shannon lifeboat costs the RNLI £1.5 million. Each Supacat launcher costs the RNLI £1 million.

11. How could you persuade the public of the benefits of all the SupaCat’s hydraulic systems and the Shannon lifeboat’s propulsion system? Why does it improve on older technology?