Magnets are magical. Don’t you feel so? They can make objects jump and dance! The sight of nails and coins clinging on to magnets is fascinating for kids. Do you know that coins retain some magnetic power even after they are detached from the magnet? We can see a live demonstration of this phenomenon in this magnetic coins science experiment. It may take time and practice to make the experiment a complete success. But when you succeed, you will agree that it was worth the effort.
What we need
Strong magnets – 2
Long ruler – 1
Books – enough to make 2 stacks
Coins (with iron content) – 5 to 6
Small can with flat base – 1
Procedure
- Create two stacks of books and keep them side by side. They should be of equal height.
- Move the stacks apart, leaving enough space for the can to be kept between the two stacks.
- Make sure that the stack of books is considerably taller than the can.
- Turn the can upside down, and place it between the book stacks.
- Fix the two magnets to both sides of the ruler. Magnets should be stuck to both sides, at the middle of the ruler.
- Place the ruler joining the two book stacks. Now we have the magnet sticking to the ruler, and hanging right on top of the upside down can.
- Fix a coin to the magnet under the ruler. Fix another one under it, and so on till we have a small tower of coins. (Remember, the tower should not touch the can yet)
- When we have the tower of coins hanging from the magnet, gently detach the topmost coin from the magnet. The other coins will still be clinging to the top coin.
- Bring down the entire stack till the bottommost coin touches the base of the can.
- Very slowly, release your hands. The tower of coins will be intact even when they are not directly touching the magnet.
- Blow air gently on one side of the coin tower, and you can see it spinning. If the blow is too hard, the tower will fall apart.
Tips: If the stack of coins is jumping back to the magnet when you release your hands, your magnet is too strong. You will need to increase the height of the stack. If the stack falls apart immediately after you release your hands, your magnet is weak. Use a stronger magnet or reduce the number of coins in the stack.
What we learn
Let us understand the reasons behind the success of the freestanding coin tower that we built in this magnetic coins science experiment. As we know, the iron content in coins makes them stick to the magnet. Ferromagnetic substances such as iron and nickel develop an internal magnetic field when placed in an external magnetic field. So while in contact with the magnet, these coins develop their own magnetic field.
The coins retain this magnetic field even when they are detached from the magnet. Their magnetism is weak, yet strong enough to feel the pull of the stronger magnet hanging above. The topmost coin in the tower feels the pull of the stronger magnetic field above, but still continues to stick to the coin beneath. This is because the magnet is farther away, but the next coin is just beneath. The moment you disturb this magnetic pull, the coins fall off.
Have you perfected this experiment? Go through our vast collection of similar Experiments. Have fun exploring!
