Notes

Magnets

The first person to discover electromagnetism was William Sturgeon .
Magnets have both a north , and south pole .
They will always have these two poles .
Even if you cut them in half and break them into pieces .
These north and south poles have a magnetic field .
The magnetic field goes out of the north pole and into the south .
Kinds of materials magnets can attract are iron , nickel , and cobalt .
We need Magnets because they help generators and electric motors work .
The worlds largest magnet weighs 50,000 tons .
The most powerful magnet in the universe is a star called magnetar .

Magnets are ancient because the origin of magnets is from as early as 600 B.C. .
It was discovered by someone named Magnes who his shoe nails get stuck to a rock that had magnetite in it .
At that time they also found more magnetic rocks in the city of Magnesia .
An early magnetic device was a compass .
People had discovered that magnets always pointed to the north and south poles when they were able to move freely .

Most metals are not attracted to magnets .
Other materials , which are steel and aluminium , can be made into powerful magnets .
They can be made by heating a ferrimagnetic material to a high temperature .
Another way magnets can be made is from rare and strong earth magnets , that turn some metals into magnets .
That's why most magnets we see around us are man-made .

Earth is just one very big magnet .
It has several north and south magnetic poles .
Earth's magnetic field is actually weaker than a fridge .
Some animals can get affected by magnets .
Birds find their way home using earth's magnetic field .