## Monday 10 June 2013

### Science: An introduction to magnets

Magnets attract only certain objects, those that contain, iron, steel, cobalt or nickel.  They have 2 poles, north and south.

When to two magnets are pulled towards each other we say that they attract, when they push apart from each other they are said to repel.

If you let your child play with the magnets they will notice that when 2 north pole are put close together they repel and when 2 south poles are pushed together they repel.  This is because with magnets opposites attract.

The planet Earth acts like a huge magnet is inside it!  It has a magnetic field that acts the same as any other magnet.

Not my best drawing ever but you get the idea

I got Naomi to draw one of these out herself, being a visual learner she likes to draw to learn.

To see how this is similar to how a magnet works you can try this mini experiment: Magnetic fields...

You will need iron filings, a magnet and a piece of card (cereal box thickness is perfect).

Before you start ask the young person you are working with: what do you think will happen when we sprinkle the iron filing on the cardboard?

What to do:

1. Place the magnet on the table and put the piece of card on top of it.
2. Sprinkle the iron on top of the card.

You will notice that the magnet makes a pattern with the iron filings.  You will see that there is more iron filings at the poles, this is because that is where the magnetic force is at its strongest.  We used a bar magnet, you might like to try a horse shoe one as well.

You might also like this mini experiment which shows up how magnets repel from each other and science is like magic!

All you need to do is get two magnets and tape them together, north pole to north pole, south pole to south pole and you will see that this happens...

You want to know a bit more?

A magnet produces a vector field, the magnetic field, at all points in the space around it. The force (F) is equal to the charge (q) times the speed of the particle times the magnitude of the field (B), or F = q*v x B. This is how you can mathematically work out the magnetic field's strength and direction.

A few fun facts about magnets:
• The Earth's magnetic field is responsible for deflecting the solar wind which are charged particles that come from the sun.
• The Earth's core is believed to be a mix (alloy) of iron and nickel, giving the Earth its own magnetic field.