M AGNETIC OR N ONMAGNETIC ?

F IRST 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.

W HAT IS M AGNETISM ? Magnetism is a force of attraction or repulsion The force of attraction pulls an object towards the magnet. The force of repulsion pushes an object away from the magnet.

M AGNETS 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

R EMEMBER Unlike poles attract Like poles repel But, that only when talking about two magnets.

P ROPERTIES OF M AGNETS Why do these magnets appear to “float” in air? The same poles are facing each other. SNNSSNSNNSSN

W HAT MATTER IS M AGNETIC ? 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.

M AGNETS ALSO HAVE A M AGNETIC F IELD 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.

M AGNETIC F IELD L INES Field 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 Magnetic Pennies 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

M AGNETIC OR NON - MAGNETIC ? Iron filings Magnetic

Copper wire Magnetic or non-magnetic? Not Magnetic

Silver spoon Magnetic or non-magnetic? NOT Magnetic Silver is Not one of the magnetic metals.

wood Magnetic or non-magnetic? Not Magnetic

Magnetic or non-magnetic? Iron nails Magnetic

M AGNETIC 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.

M AGNETIC 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.

T ALK WITH YOUR GROUP What are the three metals that are magnetic? What are two things you know about the poles of a magnet?