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:
|0.00005 lux||50 µlx||Starlight|
|400 lux||Bright room|
|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.