Magnet Mystery

Little levels (ages 4 to 6)

1. Will it stick? Guess for a paper clip, a block, a nail, a toy and a soda can, then watch the magnet.
2. Sort the drawer Sort six things into Sticks and Does not stick, then test them.
3. Through the table Slide the magnet under the table and the paper clip on top follows.
4. Push and pull North and north push apart; north and south click together.
5. Magnet fishing Only the fish with a metal ring stick to the magnet.

Big levels (ages 7 to 9)

1. Metal detective Seven metal things: only the iron and steel ones stick.
2. North and south A magnet floating on a cork spins away from north and toward south.
3. Magnet maze Lead an iron ball through a maze with a magnet on top of the glass.
4. Make a magnet Stroke a nail ten times in one direction and it picks up paper clips.
5. Electromagnet crane Switch the coil on to grab cars and off to drop them in the truck.
6. Compass The map is turned; use the needle to find north and reach the treasure.

The big ideas

• Magnets attract iron, steel, nickel and cobalt. Most things, including most metals, are not magnetic. Copper, aluminum and gold do not stick, which surprises almost everyone.

• Every magnet has a north and a south pole. Like poles repel and opposite poles attract. Cut a magnet in half and each piece has both poles again.

• The pull works at a distance and through things. Magnetism passes through wood, glass, plastic, paper and water. That is why a magnet under a table can move a clip on top.

• Iron can be made into a magnet. Inside iron are tiny magnetic regions pointing every which way. Stroking with a magnet lines them up; dropping or heating the nail scrambles them again.

• Electricity makes magnets you can switch off. A coil of wire with a current running through it is a magnet. Scrapyard cranes, doorbells and motors all use electromagnets.

• The Earth is a magnet too. A compass needle is a small magnet that lines up with the Earth's magnetic field, so it points north wherever you are.

Try it at home

1. Fridge magnet hunt Take a fridge magnet around the house and test twenty things. Sort them into sticks and doesn't stick, and look for surprises like aluminum cans and coins.
2. Paper clip puppet Put a paper clip on a sheet of card and move a magnet underneath. Try thicker things: a book, a plate, a glass of water.
3. Make a magnet Stroke a steel needle or nail 30 times in one direction with a magnet, then see if it picks up a paper clip. Drop it on the floor a few times and test again.
4. Floating compass Magnetize a needle, lay it on a small piece of cork or a leaf floating in a bowl of water, and watch it turn to point north.

Ask after playing

• Why did the soda can not stick, even though it is metal?
• What happened when the two north ends came close?
• How did the paper clip move when the magnet was under the table?