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What are magnets?
A magnet is something that can attract certain metals .
It has an invisible force that pulls the metals to itself .
This force is called magnetism .
Magnets have many uses .
They can stick things on hold things together and make machines
work.
Do your cabinets have magnets that hold the door shut.
Do you have speakers in your home.
These are made with
magnets too.
Do you have a fan in your home .
Electric fans use magnets to make the blades turn around.
Did you know that almost every machine in your house has magnets
in it.
Let's explore the world of magnets .
Now, where do we get magnets from?
Some rocks are natural magnets.
Here's a story about magnets.
Long ago,a boy in ancient
Greece walked across a big rock .
But as he walked across the rock it pulled the nails right out
of his shoes.
His shoes fell apart and
the nails stuck to the rock.
We don't know if this
story is true or not.
But we do know that the word magnet comes from the name of a
place magnesia where some of these natural magnet rocks were found.
Does a magnet attract all kinds of metals.
No there are only certain
metals that are attracted to a magnet.
They are iron , nickel and cobalt .
These metals can become magnets.
Let us now understand how do magnets work.
Magnets come in different
shapes.
They can be bar magnets, horseshoe magnets or ring magnets.
A magnet has two ends .
These are called the magnets poles.
One is called the North Pole and the other is called the South
Pole.
The north pole of a magnet attracts the South Pole of another
magnet that means it pulls the magnet toward itself .
And the South pole of a magnet attracts the North Pole of
another magnet.
But magnets don't just attract .
They can also repel or push things away.
If the North and South
Poles of different magnets attract each other which poles
Do you think repel each other?
Yes ,you're correct the poles that are the same repel each other.
So a North Pole would repel another North Pole.
And a South Pole would repel another South Pole.
Can you tell which pair of magnets will attract and which will
repel.
Yes you are right the magnets with opposite poles facing each
other will attract and the ones with similar poles facing each other will repel.
The attraction and repulsion of a magnet is due to an invisible
field around it called the magnetic field .
You may be wondering if the strength of this magnetic field is
the same everywhere in a magnet.
Let's find this out by bringing a bar magnet close to some iron
filings.
Now observe carefully you
can see that more iron filings are attracted to the ends of the magnet while
less iron filings are attracted to its middle.
This shows that strength of this magnetic field is more at the
ends and less at its center.
Let us now learn how our earth behaves as a magnet.
Have you ever seen a compass.
A compass is a tool that helps
people know which direction.
They're going in .
A compass has a needle that has been turned into a magnet .
You can turn something into a magnet by rubbing it with a magnet
.
The needle in the compass can spin .
The needle spins such that when it rests one end of the magnet
points toward the north and one toward the south.
This works because the earth is like a big magnet .
There is iron inside the earth that gives our planet its
magnetic
field.
Do you know about the
Northern Lights and the Southern Lights.
They are a natural light
display in the sky almost like fire-works .
They can be seen in the areas around the North and South
Pole.
They are caused by the
Earth's magnetic fields .
Sometimes the Sun throws out a burst of energy.
These bursts get caught
in the magnetic field around the earth.
They give off some
beautiful bright colors.
The northern and southern
lights are one of the ways we know that
earth is a big magnet.
You have learned that
magnets can pull through Earth's
atmosphere .
Can they pull through liquids such as water .
Yes they can.
Can magnets pull through solids.
Yes, magnets can pull
through solids like paper.
As we've seen magnets are useful powerful and sometimes amazing
look around you and see how many ways magnets are used.
Now let's summarize what we've learned.
