How can mechanical energy produce electricity?
When electric current flows through a coil of wire, a magnetic field is created around the wire. You will remember that from your experience in making electromagnets: that's why electromagnets work. In this activity the opposite is happening. Instead of producing a magnetic field around a coil of wire by sending an electric current through the wire.
Materials needed.
- Galvanometer
- Galvanometer coil without needle
- Strong magnet
Procedure
1. Securely attach the wires from one coil to another.
2. Hold the coil without the needle in one hand and with the other hand move the strong magnet back and forth through the centre of coil or around the coil.
3. Observe the needle on the galvanometer. Can you see a relationship in what is happening?
4. Think of some words to describe the behavior of the needle. Discuss this with your teacher and other students.
can you use the idea from this activity to design a generator? Figure out a way that you can spin a magnet within a coil of wire; spin a coil of wire within a magnetic field. Try to design your generator with more turns one coil or more than one magnet.
How it works? Scientific reason.
When electric current flows through a coil of wire, a magnetic field is created around the wire. You will remember that from your experience in making electromagnets: that's why electromagnets work. In this activity the opposite is happening. Instead of producing a magnetic field around a coil of wire by sending an electric current through the wire, we are causing electrons to flow by moving a coil of wire within a magnetic field. Because of this phenomenon, the generator, which turns coils of wire through a magnetic field, has made electricity relatively inexpensive and plentiful.
Observe the needle closely as the magnet goes through the coil and you will notice that it reverses the direction in which it is pointing each time the magnet moves back and forth. This shows that as the magnetic field moves back and forth, the electrons move back and forth or alternate their direction within the wire. Electricity produced in this manner is called alternating current.
