Light Investigation

Topics: Incandescent light bulb, Light, Lighting Pages: 2 (504 words) Published: May 19, 2013
Torches were originally invented in the stone-age by primitive cave men. Torches were made from wood and fire. As man evolved, so did the torch. Over time they became more sophisticated by using rags soaked in gasoline until Thomas Jefferson invented the light bulb – which is used in torches today. Different materials used for torches today include: Rubber

As technology progresses, torches have become smaller, more powerful and durable. They have been made powerful so that if anyone is ever in trouble, emergency teams can be there to help. The first proper torch was made in 1823 and made in Austria, Vienna by Thomas Jefferson.

Originally, a torch was a portable source of fire used as a source of light, usually a rod-shaped piece of wood with a rag soaked in pitch and/or some other flammable material wrapped around one end. There are two electric cells (batteries), a switch and a lamp (the torch bulb). The lines in the diagram represent the metal conductors which connect the system together.

The lamp and reflector make up an optical system, often intended to focus the light into a narrow beam. The plastic casing is an electrical insulator. Its shape and colour are important in making the torch attractive and easy to handle and use. In the torch, closing the switch completes the circuit and allows current to flow. Torches sometimes fail when the metal parts of the switch do not make proper contact, or when the lamp filament is 'blown'. In either case, the circuit is incomplete.

A torch is mainly used for when it’s dark and you can’t see, so you use a torch to help you see or find things. They are hand held. They can also be used for emergency lights if you’re stuck in trouble. You normally use torches by flicking up and down a switch or pressing a button to switch it on and off.

Torches are extremely important because emergency...
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