## 9. A single match or candle will light a room the size of a football stadium.

November 16, 2009

Action heroes such as Indiana Jones or even a film kid like Tom Sawyer who go into a cave, an abandoned house, a crypt or a catacomb light the entire place with one match or one candle. Is this real?

Now mathspigs, if you are interested in a career in stage/film lighting or even architecture you will need this maths.

60Watt light globe tells us how much power it uses. But some 60W globes are brighter than others. Light is measured with weird units.

USA uses Foot-candles. Can you imagine the pickup line ‘You brighten up my world like a footcandle’? A foot-candle is the brightness of a candle 1 foot away. Now think of a bubble around the candle. Brightness is mostly measured using one square foot or one square metre of that bubble:

1 LUMEN = 1 Footcandle/ft squared

1 LUX = 1 footcandle/m squared

Don’t get too hassled by these units.  As a rough rule:

1 candle = 1 LUX

From graph you can see by 3m a Birthday Cake is not very bright even in a haunted house or crypt.

Challenge: Draw a graph of the brightness of your own Birthday Cake!

Big Challenge:Draw a graph of your Teacher’s Birthday Cake!!!!!! Ahhhh!!!!

We know:

1 candle = 1 LUX

Now compare the brightness of 1 candle to the brightness of other sources of light:

Family Living Room = 50 LUX

Toilet = 80 LUX

Office = 320 – 500 LUX

Indoor lighting Range = 50 – 1,000 LUX

Outdoor moderate sun = 32,000 LUX

Outdoor FULL SUN = 130,000 LUX

If you want sufficient light to live your everyday life you’d need 80 candles just to go to the toilet!!!!!!