Infrared & Flash Cotton

What you need

1. A small amount of Flash Cotton.
2. An infrared bulb.
3. 2 Parabolic mirrors to focus the heat - you'll need to know their focal points.
4. Power supply for the bulb.
5. Retorts/supports for the flash cotton and bulb, MUST be non flammable.
6. Protective eye wear and gloves

What you do

1. Set up the mirrors opposite each other about 1m apart, with the bulb at the focal point of one, and the support for the cotton at the focal point of the other.

2. Turn on the infrared bulb

3. Place a palm full sized wad of flash cotton on the support at the focal point of the second parabolic mirror.

4. STAND WELL BACK - and wait for the flash...

What's going on

Infrared is a form of electromagnetic radiation, just like light. It has a longer wavelength than light and our eyes can't detect it, but our skin can feel it as heat.

Parabolic mirrors are specially designed to take light travelling straight towards it, in parallel rays, and reflecting it towards the mirror's focal point. Infrared light from the infrared bulb radiates out in all directions, the infrared caught by the mirror is reflected towards the other mirror, where it is focused towards the flash cotton at the second parabolic mirror.

The cotton, being soaked in flammable chemicals, ignites as the heat intensifies, demonstrating the existence of infrared as light with all its reflecting and focusing properties.

Special Safety Advice

Only use a small amount of flash cotton, and have fire safety equipment on hand. Both the light bulb and second focal point will be hot - so keep your hands clear.