This document discusses different types of simple machines and mechanisms that make life easier for humans. It describes how wheels were developed over time from log rollers to solid wheels to spoked wheels. It also mentions the use of animal power and levers as simple machines that increase mechanical advantage. Finally, it briefly outlines different types of gears and motions like linear and rotational.

1. Mechanisms These icons indicate that detailed teacher’s notes or useful web addresses are available in the Notes Page. For more detailed instructions, see the Getting Started presentation. This icon indicates the slide contains activities created in Flash. These activities are not editable.

2. Making our lives easier The aim of technology is to improve life for people. Machines and mechanisms make it easier for us to move things. Mechanisms and machines are all around us. Look around the room that you are in at the moment. Identify an everyday machine or mechanism. How does this machine or mechanism make life easier?

3. The first machines

4. Early ‘wheels’

5. From rollers to wheels No one knows for sure how the wheel was ‘invented’ . Perhaps the idea ‘developed’ in stages. Trees cut down to make log rollers . Logs cut into short pieces – solid wheels . Solid wheels lightened by cutting out bits – spokes . Rubber tyres used to improve efficiency.

6. Military machines

7. Animal power From early times people have used animals to make life easier for themselves. Horse power was used to help lift loads. Can you think of any other examples of animal powered machines?

8. Levers in action Levers are very simple machines. If you look you will see examples of levers all around. How many other examples of levers can you think of?

9. Levers

10. Mechanical advantage Levers can be used to increase our strength. With a long lever, a small force can be used to raise a large load. This gives a mechanical advantage . Load = 50 newtons Effort = 10 newtons Load = 50 N Effort = 10 N MA = 5 Mechanical advantage (MA) = load effort

11. Velocity ratio Velocity ratio is used to compare the distances moved by load and effort. Velocity ratio = Here, in one second, the effort moves 1 metre and the load moves 4 metres. Because the applied force is greater than the load, the load moves faster (and further) than the effort. distance moved by effort distance moved by load

12. Torque Torque = force x distance. The force that is used to undo a nut and bolt is a turning force. This turning force is called torque . The longer the handle on the spanner the easier it will be to undo the nut because the torque will be greater.

13. Types of motion

14. Types of gears Gears used to change rotation into linear motion: Gears used to change rotational motion through 90 degrees: bevel gears rack and pinion worm and wheel

15. Inside the black box