MAKING TRAFFIC LIGHTS:

ITEMS REQUIRED:

Two wooden strips: one 12”x4”x1” and the other 8”x4”x1”-Three bulbs: each 3 volt (one red, one green, one orange)- Three bulb holders- Enameled copper wire- Two dry cells each 1.5 volt-4 drawing pins- One U-clip-Two wood screws

PROCEDURE:

Take two wooden strips-one 12”x4”x1” and the other 8”x4”x1”. Put them at right angles and fid=x them with the help of wood screws. Put three bulb holders in a line and wire them in parallel. Insert the bulbs in the holders: top-red, middle-orange and bottom-green. Fix the three wires from three bulbs at the base with drawing pins and put a fourth pin by pressing a U-clip under it. One end of it should be straightened so that it can be pressed against any of the three pins. This will act as a switch. Connect the two dry cells in series, i.e. the positive terminal to negative terminal of the other, to each bulb. Connect the common wire from the bulbs to the positive terminal of the dry cell combination. Connect one wire from negative terminal of the dry cell combination to the U-clip. Your model is ready. Now, when you press the straightened edge of the clip against any of the three pins, one of the three bulbs will glow.