Experiment 5:

Magnetise a nail?

In this experiment, students can create their own magnet.

1 large nail ( 7 or 8 cm long )
1 piece of electrical wire ( copper )
1 nine-volt battery

Start by wrapping the electrical wire around the nail (wrap it around about 40 times).
The more wire which is around the nail, the greater the intensity of the magnetic field which is generated.

Bring a small object made of metal (like a sewing needle, a paperclip or a screw) close to the nail. The nail will stick to the object

Now attach the wire to the battery's terminals.

Your electromagnet will attract small items made of iron or steel, or certain other alloys. Very powerful electromagnets also work on nickel and cobalt.

After you have unplugged the wire, the nail will retain its magnetic power for some time. But it will lose its magnetic properties if you heat it or strike it against something hard, like a table.

The invention of the telegraph:
The telegraph invented by Samuel Morse in 1837, was one of the most revolutionary inventions based on electromagnetism. Morse had the idea of an electric current making an electromagnet work intermittently on a piece of soft iron to which a writing point was attached. If the current failed for a short time, the point would stamp a dot on a moving strip of paper. If the flow of electricity current lasted longer, the point would impress slightly longer. Morse worked out a code alphabet (Morse Code) with letters are represented by dots and dashes. His telegraph made it possible to communicate across a greater distance than could be seen - unlike light signals, smoke signals or flag signalling, which each depended on the sender and the receiver being at a certain place at a certain time