### Making an Electric Fuse & How Energy Gets Transferred

Science Projects Index

Making an Electric Fuse

Make a circuit using a 9-volt battery and a bulb of 5 volts. Cut the wire leading to the positive terminal. Place the cut ends on a table and then connect each other with a strand of a very fine wire using adhesive tapes. Put on the switch, the bulb lights up, but after a few seconds the bulb goes off. The fine wire has melted due to the fact that being so thin, it is unable to conduct so much electricity and in the process of doing so, has heated up. This is how an electric fuse works.

### How Energy Gets Transferred

Take four or five marbles. Keep them in a row on a table. Take one at the end nearest to you and roll it towards the row of marbles so as to hit it on that end. You will see the marble at the other end moving away while the other marbles remain stationary. This is a classic example of how energy is transferred through objects.

On a three-inch nail, wind some insulated copper wire. Care should be taken to see that when you wind, they don't overlap. Strip off the ends of the wire and connect them to a 9-volt battery. The nail has now become an electromagnet. If you bring any small iron objects like a nail, paper clip, pin etc., you will find them getting attracted to the electromagnet. This phenomenon is known as Electromagnetic Induction. And the relation between the direction of flow of electricity and the direction of the magnetic forces are dealt with in Faraday's Laws of Electromagnetic Induction.

Keep a magnet on a piece of white paper on a table. Pour some iron filings on it. You will find a strange manner in which the filings stick to the poles. And if you keep the magnet under the paper and pour the filing on the paper and then give a slight shake to the paper you will see the filings arrange themselves in definite lines starting from each pole. Some lines would connect to both poles. These lines give an indication of the limits of the magnetic field of that magnet.