Michael Faraday was one of the most important experimental physicists who ever lived. His work in understanding and using electricity has allowed many of our technological advances in the last two centuries.

This is not intended to be a long exercise, rather it is a way to get the students to think about what forms of motion energy which could be converted into electricity.   The class can work individually on their own work sheet or the whole class can work together to come up with ideas for micro-generation.  They may enjoy working out the pitfalls in any of their ideas.

If they are struggling to come up with ideas here are a few to inspire them...

Water flowing down a plug hole
Water flowing from a tap
Flushing a toilet (movement from the water entering not leaving the toilet!)
People moving while watching tv - could they be put on electricity generating bikes?
Air flowing in and out of windows
Hot air or steam rising above a cooker
A hamster on a wheel!

Students may suggest movement which is created by an electric motor, they may want to think about how efficient it would be to use this movement to convert back into electricity!

 

Curriculum Links

Electric motors and electric induction
Science

Working scientifically

Scientific attitudes

  • understand that scientific methods and theories develop as earlier explanations are modified to take account of new evidence and ideas, together with the importance of publishing results and peer review

Physics

Calculation of fuel uses and costs in the domestic context

  • fuels and energy resources

Energy changes and transfers

  • processes that involve energy transfer: changing motion, dropping an object, completing an electrical circuit, stretching a spring, metabolism of food, burning fuels.

Magnetism

  • the magnetic effect of a current, electromagnets, D.C. motors (principles only)
History
  • Ideas, political power, industry and empire: Britain, 1745-1901

Scottish Curriculum Links:

Science

SCN 3-04a

Planet Earth - Energy sources and sustainability

I can use my knowledge of the different ways in which heat is transferred between hot and cold objects and the thermal conductivity of materials to improve energy efficiency in buildings or other systems.

SCN 3-04b

Planet Earth - Energy sources and sustainability

By investigating renewable energy sources and taking part in practical activities to harness them, I can discuss their benefits and potential problems.

SCN 4-04a

Planet Earth - Energy sources and sustainability

By contributing to an investigation on different ways of meeting society's energy needs, I can express an informed view on the risks and benefits of different energy sources, including those produced from plants.

SCN 4-08a

Forces, electricity and waves - Forces

Literacy and English

LIT 3-28a

Writing - Creating texts

Technologies

 

TCH 3-01a

Technological developments in society

From my studies of technologies in the world around me, I can begin to understand the relationship between key scientific principles and technological developments

TCH 4-01a

Technological developments in society

I can compare traditional with contemporary production methods to assess their contribution in the world around me and explain the impact of related technological changes.

Electric motors and electric induction

Faraday was involved in lots of different subjects in physics and chemistry, but it is his early work which has probably had the biggest impact on our lives.  He connected electricity and magnetism in a way that has brought us the electric motor and the electric generator.

In the early 19th century there were a number of people working on electricity and magnetism. At this time Alessandro Volta invented the battery, which meant future physicists could carry out experiments with a constant, portable source of electricity. And Hans Oersted discovered electromagnetism.

How do electricity and magnetism fit together in electromagnetism? When a current flows through a wire there is a tiny magnetic field around the wire.  If you wind the wire up into a coil, much like a spring, these little magnetic fields all add up and the end result behaves just like a permanent magnet.

magnets_500

Michael Faraday had met Alessandro Volta in Italy in 1814 and knew about Oersted's work too. He combined the two to make his electric motor.

Faraday's motor combined a permanent magnet in a C shape with the north and south poles facing each other, and a separate coil of wire in the middle.  When electricity flowed through the wire it became an electromagnet. The magnetic fields of the coil and the permanent magnet repel each other and the coil of wire spins!

motor_500

Ten years later, Faraday managed to reverse the process and make an electricity generator.  He found that moving the wire in a magnetic field 'induced' current in the wire.  This was a huge breakthrough, and most of the electricity we use today is produced in this way.  The only difference between different types of electricity generation is the way we get the wire to move.

Key fact: Michael Faraday used his understanding of electricity and magnetism to discover how electricity could be generated by moving wire inside a magnetic field.

 

 

wind turbine_300Making it move

Electricity is generated by moving a coil of wire (the turbine) in a magnetic field.  Faraday's generator changes kinetic (motion) energy into electrical energy.

Although power stations work on a huge scale, micro-generation is becoming popular.  In micro-generation, small amounts of electricity are produced from many sources, adding up to a lot of extra electricity.

If you wanted to produce electricity at home you could attach a generator to almost anything that moves!  Have a look around your home and school and try and find a new source of electricity...

You can use this worksheet to fill in your answers.

 

1. Think about conventional sources of power as a starting point...

Coal, oil and gas

Burned to heat water and the resultant steam turns the turbine.

Hydroelectric

Moving water turns the turbine.

Wind power

The wind turns the blade of a windmill which turns the turbine.

 

2. Have a look around your home and think of all the places where there is movement.  Make a list in each room....  this might be moving water, moving air, even moving people.

 

3. Now choose one of your sources of movement. You don't need to worry about how a generator might harness this movement but try to think of any  potential drawbacks or hazards with its use.

 

4. Would this be a constant source of electricity or would you only have a power a few times a day?

 

5. Do you think this would be a good source of electricity?

 

Electrical energy is not created out of thin air.  Energy is transformed from one type to another.  The ultimate source of energy for conventional sources of power such as coal, oil, gas, hydroelectric and wind, comes from the Sun.

Coal is made from plants that lived millions of years ago; oil and gas come from sea creatures that lived millions of years ago and would have fed on green algae.  The wind is caused by the Sun heating the air and making the air move.  Hydroelectric power is driven by water flowing in rivers, these rivers are fed by rain which is caused by the Sun evaporating water from the sea.

 

6. Can you work out where the energy comes from that you have used to generate your electricity?