To explain theoretically to kids as to how a generator works and to explain practically by making a simple generator in front of them are two different things. There is nothing better than explaining kids the concepts of electricity by constructing a small generator before their eyes, which would enable them not only to understand the process of generating electricity but also know the construction of simple generator. In this article on easy science projects for kids, we will learn about the procedure of making a simple generator that can light up a small torch bulb. Before getting into the actual procedure we will quickly have a look on the working of the generator and what all things we require in making one.
Working of a Generator
If we get to the very basics of the generator then a generator is nothing but an arrangement of a wire coil rotating within the magnetic field of a series of magnets. When the metal wire coil rotates under the influence of a magnetic field, a voltage is induced in the wire windings. It is to note that as the number of windings in the coil increases the voltage induced in the coil also increases. Also, more the magnetic strength more is the voltage generated.
The arrangement of the generator should be such that the coil is continuously under the effect of the magnetic field. On the basis of the application, it is decided if either the coil will rotate or the magnets will rotate. For making such an arrangement, we will require a material which is easily available and which can concentrate large magnetic field. An iron nail is the best choice for this as it is cylindrical in shape and can concentrate the magnetic field easily. Moreover, as the nail can easily wound the wire coil around it, more magnetic flux is drawn, increasing the overall efficiency of the whole generating unit.
One more important aspect is the thickness of the wire. Thicker the wire, more the amount of voltage induced and less power lost. But in making a simple generator, large windings won’t be able to accommodate on the nail and would thus reduce the power generated. To list down, we will need the following items –
Long iron nail with large head
A small torch bulb
Procedure for Making a Generator
First take a cardboard and make two equal circles on it, proportionate to the nail. Cut the two circles appropriately and make holes exactly in center of each of them. Take the iron nail and push one circle right up to the head. It is to note that the nail should be rust free, has a large head and is long enough to accommodate enough windings.
Then take an insulation tape and wind it near the sharper edge up to 2-3 centimeters. Now take the second circle and push it right till the insulated part on the nail end. Use the same insulation tape on each side of the circles to fix them. Once done, it will resemble a spool wherein the windings are now to be wounded.
Now take a copper wire and start winding it between the two circles. Before doing this, make sure that at least 10 centimeter of wire is left free at the start end. Keep making windings, layers wise, one above the other, till the cardboard circles can hold the windings between them. Once done, leave at least 10 centimeter of the wire free at the other end also.
Then, take free ends of the wire, remove their insulation and wire them to a small torch bulb. Now bring a magnet close to the head of the nail and start moving it in a brisk and rapid motion around the head. The magnet when moved around the coil shouldn’t be more than five millimeter away from the coil. After some time the bulb will glow, indicating electricity generation.
This is the most basic form of generator that can be made to explain the creation of electricity. However, more complex mechanism can also be made by making the magnet move automatically around the nail or by making a simple hand cranked generator as shown in the figure.
THE CREATIVE SCIENCE CENTRE**,** Dr Jonathan Hare, The University of Sussex