“How, where or when we’re magnets found or made?” asks Sam (11)

Thanks for the question Sam. Magnets and magnetism was first discovered about  9000 years ago. A long time ago. It was found in rocks and called ‘lodestone’. Lodestone is a naturally occurring compound of iron. It is thought that it was magnetised by lightning strikes.

We will make our own magnets by using a slightly weaker form of electricity.  Here are my team.

Firstly let us try to make a magnet (without using lightning)

You will need a battery and a length of wire and some paperclips. The a collection of nails. Try and find as many different nails as you can. Wrap the wire around the nail and sellotape the bare wire ends to the terminals of the battery. See the diagram below. See how many paperclips you can pick up? Are some nails better than others?

DO NOT USE MAINS ELECTRICITY. IT IS VERY DANGEROUS. 

You might have found out that only certain metals can be made into magnets. These metals are called ferromagnetic metals.

Included in this group are the metal iron and the alloys of iron with the metals cobalt, nickel.

It is thought that in these metals (including iron) have some electrons called ‘free electrons’ (not sure what an electron is, then go to Science Master Special – Atoms and Atomic Structure). It is these ‘free electrons’ that are involved in magnetism. In the alloys the  ‘free’ electrons align themselves with the magnetism of the external magnet, making a (for the alloys) a permanent magnet.

Look at the short video I have made below. In the ferromagnetic metal (iron alloy) crystal domains you will see free electrons. In the metal these will be moving freely. As they begin to interact with the external magnetic field, they begin to align themselves, making a permanent magnet.

Makeda (7) asked “How does the electricity make a magnet?”

Makeda what a great question, and my answer is, I don’t know. We know that electricity can make a magnet or even give a wire magnetic properties. There are other things which we know but it’s a bit like gravity. We know that big things, like the Earth and the Sun attract smaller things – the Sun attracts the Earth, the Earth attracts you and me BUT we do not know what gravity is, we just know what it does.

So I asked my friends about this.

Absolutely, thank you friends. Electricity is linked to things called electrons that are attached to other things called atoms that make up all of the things that we see around us, and us.

There are some special materials that you might have discovered called ‘metals’. Metals allow the stuff which we call electricity to flow through them. In metals the electrons carry the electricity and when they start moving they not only start moving the electricity there movement creates a magnetic field.

So lets carry out some experiments to investigate electricity and magnetism.

Let us make a simple circuit with a battery and a switch  and add a compass, close to the circuit.   Why a compass? A compass is a very small magnet and will detect other magnets by trying to move towards them or away from them. Switch on the circuit and see what happens. Switch off and again see what happens.

 

Let us know what you saw.

Maryam (age 10) asked a question on forces. “What do forces have to do with science?”

Maryam

What an excellent question. How do I answer this? Firstly I think we need to know what we mean by science. Here is what my friends said when I asked them the question.

Balancing Forces

My favourite definition of science is that it is ‘applied curiosity’. People who enjoy science have a curiosity about the physical and natural world that surrounds them. This leads them to investigate it.

Look at the see-saw in the picture above. Why does a small mass seem to balance a larger mass? Lets move the masses around and see if we can get other positions where they balance? This is curiosity in action.

So what about forces, are they part of the natural world or the physical world? What is a force?

The forces we meet every day are pushes and pulls. Pushes and pulls make things move.

Gravity is another force … jump off a chair and you are pulled to the ground, you moved because of the pull of gravity. Another force is friction – how does that affect movement? Force and movement are therefore intertwined. Investigate movement and you are investigating forces. And that leads to lots of questions. Do things always move at the same speed when a force is applied? Curiosity, curiosity, curiosity.

So please show your curiosity by asking more questions and I leave you with a question of your own. Are forces part of the natural world or the physical one, or both, or neither?

I hope this gives you some answers to your excellent question. Any more questions?