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Knee Power

Topic: 4F Circuits and conductors

A device has been created which allows people to generate electricity simply by taking a stroll to the shops to buy a newspaper. The invention generates enough electricity from the motion of the legs to power the walker's mobile phone and MP3 player while they're out and about.
Researchers who developed the mechanism, an adapted knee brace, said it has the potential to be used in prosthetic limbs and pacemakers, or by anyone without easy access to electricity.

In this activity children design a circuit for a flashing light powered by the knee brace. They consider what the advantages and the problems might be.

Large activity image
 
Try the Activity Learning Objective

Click to Download Knee Power activity
Knee Power activity

Click to Download Knee Power teacher notes
Knee Power teacher notes

   

You will need Acrobat Reader installed to open the activity sheets.

You will also need the latest version of the flash player to be able to play swf files.

· why devices in some circuits shown in drawings will work but devices in other circuits will not

Children will demonstrate this by completing the task on page 2 successfully.

· that in a circuit a switch turns a specific device on or off

Children will demonstrate this by completing the task on page 3 successfully.

· how switches works

Children will demonstrate this by completing the task on page 3 successfully.

· explain that metals are used because they are good conductors and plastics because they are insulators

Children will demonstrate this by completing the task on page 3 successfully.

· suggest a way of changing the brightness of a bulb and predict what will happen
Children will demonstrate this by completing the task on page 4 successfully.

   
Curriculum Link

Science:

QCA Unit 4F: Circuits and Conductors

· that a circuit needs a power source
· that a complete circuit is needed for a device to work
· that a switch can be used to make or break a circuit to turn things on or off (using both batteries or mains)
· that metals are good conductors of electricity, most other materials are not and that metals are used for cables and wire
· to make predictions about the effect of including additional batteries in a circuit
· how to change the brightness of bulbs and speed of a motor in a circuit
· to make suggestions about what can be investigated and predictions about what will happen
· to plan to change one factor and keep others constant
· to make comparisons indicating whether the results support the prediction made


Scientific enquiry
· turning ideas into a form that can be tested, making a prediction
· making observations
· deciding whether the evidence supports the prediction and suggesting explanations in terms of their knowledge of science.

 
Running the Activity

Introducing the activity

· Display Page 1 through a projector or as an OHT. Discuss the images with the children. The news is that there is a new invention that makes electricity while you walk or run.

- What are the advantages of this?
- Can you think of the sort of people who would find this particularly useful?

Introducing the activity

· Display Page 1 through a projector or as an OHT. Discuss the images with the children. The news is that there is a new invention that makes electricity while you walk or run.

- What are the advantages of this?
- Can you think of the sort of people who would find this particularly useful?

 
Web Links

Times Online
The news story behind the activity

BBC Science Clips
An interactive circuit in which children aged 8-9 can change the ratio of bulbs to batteries and can try out different materials to see which conduct.

BBC KS2 Bitesize
An animated KS2 Bitesize activity for the Science topic.

Blobz
An interactive site which includes activities and a quiz. Highly recommended.

 
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