MAGNETIC OR NONMAGNETIC?

FIRST SOME REVIEW…

All matter has measurable physical properties.

Those properties determine how matter is classified, changed, and used.

Magnetism is one physical property of matter.

WHAT IS MAGNETISM? Magnetism is a force of

attraction or repulsionThe force of attraction pulls an

object towards the magnet.

The force of repulsion pushes an object away from the magnet.

MAGNETS ARE THE TOOLS USED TO MEASURE MAGNETISM poles – two ends of a magnet

every magnet has two poles north (N) pole south (S) pole

even if you break a magnet in half, each half will have a north pole and a south pole

REMEMBER Unlike poles attract

Like poles repel

But, that only when talking about two magnets.

PROPERTIES OF MAGNETS Why do these magnets appear to “float” in air?

The same poles are facing each other. S

N

NS

SN

WHAT MATTER IS MAGNETIC? Metals that contain iron, nickel, and cobalt

are magnetic. In other words, a magnet will pull them.

Not all metals are magnetic. Aluminum and copper are examples of

metals that are NOT magnetic.

What is the ONLY way to tell if an object is magnetic?

Use a magnet.

Magnetite is a special rock that is magnetic.

Why are these nails attracted to the

magnetite?

They are made of iron.

MAGNETS ALSO HAVE A MAGNETIC FIELD

Every magnet has a magnetic field around it. It can be thought of as a line of force running from the north end of the magnet to the south end of a magnet.

Earth’s magnetic field is what causes the needle of a compass to point north and south.

MAGNETIC FIELD LINESField lines come together where the magnetic force is strong, and spread out where it is weak.

In a bar magnet, force field lines spread out from one pole and come together towards the other.

The magnetic force is strongest near the poles where they come together.

Now that you know more about magnetism, let’s see if you can find the magnetic

items.

Cobalt drill bits

Magnetic or non-magnetic?

Magnetic

penny

Magnetic or non-magnetic?Not MagneticPennies are made of copper and copper is NOT magnetic.

aluminum

Magnetic or non-magnetic?

Not Magnetic.Remember only iron, nickel, and cobalt are magnetic metals.

Porcelain vase

Magnetic or non-magnetic?

Not Magnetic

MAGNETIC OR NON-MAGNETIC?

Iron filings

Magnetic

Copper wire

Magnetic or non-magnetic?

Not Magnetic

Silver spoon

Magnetic or non-magnetic?

NOT MagneticSilver is Not one of the magnetic metals.

wood

Magnetic or non-magnetic?

Not Magnetic

Magnetic or non-magnetic?

Iron nails

Magnetic

MAGNETIC OR NON-MAGNETIC?

Nickel coins from Denmark

Magnetic

FACT: The nickels made in the United States are not made of nickel – they are made of copper so they are not magnetic.

MAGNETIC OR NON-MAGNETIC?

Paper clips

Trick question – since you don’t know if these paper clips are aluminum or iron, you don’t know if they are magnetic until you put them near a magnet.

TALK WITH YOUR GROUP What are the three metals that are

magnetic? What are two things you know about

the poles of a magnet?