1. Marshmallow Crossbow How does it work?
Can you use the following words in your description;
Force
mass
Elastic
Potential energy
Change in shape

2. When springs are compressed or stretched they store elastic potential energy. Same is true when cocking a crossbow.
When they are released they return to their original shape, often very quickly, as their elastic potential energy is transferred into kinetic energy.

3. This crater on Mars is named after me
I drew this image of a flea using an early microscope
The truth is, the Science of Nature has been already too long made only a work of the Brain and the Fancy: It is now high time that it should return to the plainness and soundness of Observations on material and obvious things.

4. Hooke’s Law

5. Learning Objectives By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!

6. Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Way back when…
Back in the 1600’s if you wanted to weigh something the only method was to use a balance and compare the weight to something else. Hooke’s discovery that you could use the extension of a spring to find the force of gravity caused by an objects weight led to brand new technologies, such as scales.

7. How do Scales Work Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
How do Scales Work
Weight is distributed across scales, this is focused onto one bar which pulls at a spring. Extension of spring is measured and force is calculated.

8. Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Can you think of any other objects or systems that use this ability to store elastic potential energy?

9. Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Stretching Springs
How much a certain spring extends depends on the force applied and the spring constant.  
This is a measure of the stiffness of the spring and it is measured in newtons per metre (N/m).
The higher the spring constant the stiffer the spring and the less it extends for a given force.

10. Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Stretching Springs
You are going to be finding the spring constant by placing masses on a spring and watching to see how much it extends.

11. Recording your Results
Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Recording your Results
Table while you are working (use a ruler and a pencil)
Graph once you have a full set of results – you should have at least 10. Plot extension on the x-axis and the force on the y-axis.

12. Recording your Results
Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Recording your Results
Table while you are working (use a ruler and a pencil)
Graph once you have a full set of results – you should have at least 10. Plot extension on the x-axis and the force on the y-axis.

13. Different practical – same ideas… What’s wrong with the graph?
Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Different practical – same ideas… What’s wrong with the graph?

14. Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!

15. Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!

16. How Close Were You? Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
How Close Were You?
Force (N)
Extension (m)

17. Calculating Gradients
Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Calculating Gradients
Line of Best fit Y X
Calculating Gradient
Line of Best fit Gradient =
length of Y/ length of X
Make sure you are calculating your gradient over the straight line part of the graph.

18. Putting it Together F = k  e
Learning Objectives
By the end of this lesson you should...
Describe how a force acting on an object can cause a change in shape.
Explain what elastic potential energy is and demonstrate how to store it in a spring.
Practise drawing coursework worthy graphs and tables!
Putting it Together
The relationship between force, spring constant and extension is represented in this equation.
force = spring constant  extension
(newtons, N) (newtons per metre, N/m) (metres, m)
F = k  e