Renewable Energy: Uses of Electromagnetism

Introduction
Public summary: 

Explore how we can use the power of electromagnetism to power our day to day lives!

Making power using wind and water!
Useful information
Kit List: 

1. Generating power
- Small ammeter and coil. Bar magnet of some sort that fits through the hole
- Green rotating generator. Clamps to attach it to a table.
- Wooden box with bulbs/handle/generator
(these are taken from the electromagnetism experiment)

Invitica Renewable Energy Kit
This has a base station, a extension piece, wind turbine, water turbine, solar panel (not that useful for this) and some plastic tubing. There's also a manual explaining how it links into curriculum. The base station has 4 inserts which you can use, an ammeter, a buzzer, a light and some gear things.

Packing Away: 

This is currently occupying the space in electromagnetism box which is freed up by taking all the broken items out, when they get fixed we'll see what happens.

Explanation
Explanation: 

1. Generating Power

There are 3 different power generating bits, in increasing level of usefulness.

Magnet, coil and ammeter

This has a coil of copper wire attached to a small ammeter. When you wave a magnet through the hole in the middle of the wire you get a reading on the wire. Some things to talk about/do with it are:

  • What are the objects? Coil is made of copper wire, this is a good electrical conductor. The setup as a whole is an electrical circuit (components linked together in a circuit). The meter looks like it might measure something (cf weighing scales), it measures the amount of electrical current (or just electricity) going round the circuit.
  • Do we get more electricity by moving fast or slow? Does it work if we're not moving at all?
  • Is this very much electricity? The scale on the ammeter is microamps (the funny squiggle is the Greek letter mu), talking (or asking questions about) millimetres, metres and kilometres is a good warm-up to explaining that microamps is a small unit. Older kids might know that fuses have amp ratings on them.
  • What do the positive/negative readings mean? It tells us which way the electricity is going round the circuit, notice that it changes if we move magnet in a different direction, or swap north/south poles.
  • How can we get more electricity? Good ideas are moving faster (and moving in circles is easier than up/down), stronger magnet or more coils.

This then leads nicely onto the next bit...

Rotating generator (green)

This has most of the improvements suggested above (show to them the larger magnet, more coils), and if you spin the handle fast enough it will give you enough electricity to light a bulb. Things to talk about:

  • The faster you spin it, the brighter it is.
  • Does it matter which way round you turn it? No.
  • [more advanced]If the bulb is an LED rather than a filament bulb then it will only light half of the time, with frequency=rate of turning the handle. This is because the current is alternating ('going backwards and forwards') and it only lights when the current is going one way.

Generator in a box

This is a better version of the previous one, but it's all hidden in a box which means visitors can't see what is going on as well. There are two bulbs that can be switched on or off, and also a voltmeter/ammeter. Things to do:

  • Start someone off turning the handle and then increase the wattage of bulbs turned on gradually. They will find that it gets harder to turn as you do this. Talk about needing to put extra energy in to get more light out (the energy is coming from them, not from the magnet/coil which just convert kinetic/moving energy into electrical energy)
  • [More advanced]Look at the ammeter/voltmeter. When a bulb is fully lit how do those readings compare to the wattage of the bulb (P=IV).

Generating in real life
Power generation: How many watts are the bulbs you have at home? If it's this hard to turn a handle to make 10W of bulbs light, how hard would it be to power all the bulbs in your house? How about all the bulbs, TVs,... in town X? This is really where our power comes from, what better ways are there of turning the handle (wind farms are the easiest example for small kids

  • Hamster in a wheel. This is like bike light dynamos! Sadly hamsters don't travel in our boxes very well.
  • Wind power. You can try the model turbine with a hair dryer or fan.
  • Water power. We use these in dams where the water flows down and through a turbine. To use this put one end of the tubing on a tap and the other in the sink, this model the water flowing down hill.

There's also the solar power but that uses a different principle.

Risk Assessment
Date risk assesment last checked: 
Tue, 06/11/2018
Risk assesment checked by: 
Tdwebster
Risk Assessment: 
DESCRIPTION Lots of experiments about magnetism and electromagnetism
RISKS
  • 1. Overheating of coils/wire -> burns
  • 2. Powerful magnets shattering
  • 3. Rotating motor could be dangerous
  • 4. Visitor or demonstrator catching fingers in generator as they turn the handle on the generator
  • 5. Heavy Generators and Motors could fall and hit someone.
  • ACTION TO BE TAKEN TO MINIMISE RISKS
  • 1. Do not put too much current through a coil/wire, if it is getting hot, turn it down
  • 2. Warn visitors if you give them a magnet.
    • Use the minimum number of free magnets
    • Keep the magnets under control
    • Cover with tape to reduce impact, and contain any shards
    • Pad edges of magnet to reduce finger trap
  • 3. Keep kids' fingers away - if it needs pushing it should be done on the axle, not the armature
  • 4. Place generator on flat surface so visitors can't catch their fingers underneath so easily.
    • Tell visitors to hold only the rotating part of the generator handle and not the entire handle.
    • Keep control of the visitors at all times and don't let them get overexcited while turning the handle
  • 5. Use clamps to keep generators and motor firmly attached to table.
  • ACTION TO BE TAKEN IN THE EVENT OF AN ACCIDENT
  • 1. If there is a burn, run under cold water for ten minutes, call a first aider. In event of fire, follow procedure in venue RA (raise alarm, evacuate)
  • 2. Call first aider in case of injury
  • 3. Call first aider in case of injury
  • 4. Call first aider in case of injury
  • 5. Call first aider in event of injury.
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