Primary Science Applications
For primary science, all the investigations needed can centre around the simple
electro-magnet. This can be made by winding about 20-40 tight, neat turns around
an iron nail and connecting the ends of this coil to 1 or 2 torch-sized 1.5v
batteries. Once used, the nail may retain some magnetism, even when the current
is switched off
.
Some Key Questions
- Can you make an electro-magnet using ..............
- How can you make your electro-magnet lift more paper clips?
- How can you reverse the polarity of your magnet?
- Can you use electro-magnetism and Lego-Technik to raise and lower a barrier
or signal?
- Can you make an electro-magnetic lock for this box?
Precautions
- The magnetic effect can be adequately produced by 2-3 1.5v batteries.
- Higher voltages or mains driven Lab Packs may cause more effects than you
need!
- The electro-mag coil can get surprisingly hot especially when thin wire
is used or a number of batteries.
- Do not use rechargeable batteries for this work - they may overheat.
Contents
History of magnetism, What is a magnet
What do magnets do, Test for a magnet
Magnetic fields
The Earth's magnetic field
Theory of magnetism
Induced magnetism
Magnetic properties of iron and steel
Storing magnets
Making a magnet
Electro-magnets
Fleming's Left Hand Rule
Self assessment
Comments, reflections and study action plan