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Equipment

Light Meter
AKA: Lux Meter

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Fig 1: Simple light meter
Fig 1
Fig 2
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Summary

A device which measures the intensity of light.

Operation

Light meters are used in science to measure the intensity of ambient light. Especially useful in some biology lessons when looking at animal habitats. Measuring light levels in 'choice chambers' can give a clear indication of what levels an animal prefers.

Both very simple types (see Fig 1) which just give an approximate indication of brightness and very accurate professional meters are available through lab suppliers. For upper school photoluminescence type lessons where exact levels are to be monitored, the second type would best suit whereas many lower school 'light' lessons would be more than catered for using inexpensive meters.

Lux (lx) is the unit of illuminance. It is used as a measure of the intensity of light. A relative table of intensities can be seen below:

Illuminance Abbr. Example
0.00005 lux 50 µlx Starlight
1 lux   Moonlight
10 lux   Candlelight
400 lux   Bright room
400 lux   Sunrise
1000 lux 1 klx TV studio
10000 lux 10 klx  
32000 lux 32 klx Minimum sunlight on average day
100000 lux 100 klx Minimum sunlight on average day

Most dataloggers now come with light sensors or have light sensors that can be purchased separately.

Safety

 CautionThe contents of this page are for information only. Please refer to CLEAPSS or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.