1. Learning Outcomes Understand:
the different classes of levers found in the body
mechanical advantages.
Be able to:
Identify, with examples, the different classes of levers

2. What is a lever? Discuss in pairs and come up with a definition.
Dictionary Definition: rigid bar resting on a pivot, used to move a heavy or firmly fixed load with one end when pressure is applied to the other.

3. Key Words Fulcrum - the part of a lever system that pivots.
Joints are the fulcrums in the body’s lever system
Resistance/load – the load to be moved by a lever system.
usually involves weight when the body’s lever systems are involved.
Effort – the force applied to move the resistance or weight
in the body, the effort is provided by muscles exerting a force.

4. Can you identify where the fulcrum, effort and resistance is?
This is an example of a 1st class lever
Effort
Fulcrum

5. Can you identify where the fulcrum, effort and resistance is?
This is an example of a 2nd class lever
Effort
Fulcrum

6. Can you identify where the fulcrum, effort and resistance is?
This is an example of a 3rd class lever.
Resistance

7. TASK Draw linear diagrams of each lever and label correctly p27-28.
Write down the key terms for 1st, 2nd and 3rd class levers.
Note down the rapid recall box on p 28.

8. Examples of lever systems in the body: match them up.

9. Storyboard: linear diag – example – example in the body
Triangle =Fulcrum
Force = effort
Load = resistance

10. Extension
Read the definition for mechanical advantage and look at the linear diagram.
Write out the definition and draw the linear diagram.

11. Homework Print out the storyboard and stick in your notebook
Read p27-28 to consolidate your understanding
Exam question

12. Lesson 2: progress check
What can you remember about levers?
In pairs:
Use the play-doh, ball and straw to
create the 3 types of lever.
Take a picture with your ipad
What is going to represent the lever?
What is the play doh going to represent?
What is the ball going to represent?

13. Mechanical advantage
Go back to read the definition and look at your linear diagram.
Now read p.29 to understand how the distance between the fulcrum – effort arm and fulcrum – resistance arm, have a purpose.

14. Force of 500N to lift the load
What happens when you move the fulcrum closer to the resistance/load?
Only requires a force of 100N – the distance between the fulcrum and resistance arm is shorter meaning…
advantage of being able to move a heavy weight

15. Ankle joint: 2nd class lever
Draw a linear diagram to show how the second class lever operates at the ankle (p. 176)
What do you notice about the resistance arm and effort arm?
RA shorter than EA
Action of the effort (gastrocnemius muscle) easily moves the resistance…which is the weight of the body.

16. what class of lever is this??
What happens if the fulcrum is closer to the effort?
what class of lever is this??
Creates a short effort arm
Gives rapid movements over a large range of movement.

17. What class of lever is it?
Fulcrum
Effort
TASK: label
Fulcrum
Effort
Resistance/load
Effort arm
Resistance arm
What class of lever is it?
Resistance

18. Elbow joint: 1st class lever
Draw a linear diagram to show how the 1st class lever operates at the ankle (p. 175)
What do you notice about the resistance arm and effort arm?
EA shorter than RA
Allows the hand to move very quickly and through a large range of motion.