light sticks

[Hgrove]

I bought from Tesco (for a Hallowe'en party we had) some plastic sticks.  When you take them out of the packet you have to bend them and I think you hear a slight crack.  They then begin to glow.  How does this work? (P.S. have read article about glow in the dark toys here on the AB but I think this is different?)

[Philtaz]

The crack is a seal breaking between two chemicals(don't know what they are though!) which when mixed together produce the fluorescent light.

[sammy snake]

I don't know how they work but a Company I worked for a few years ago had these deposited about the buiding in various places - they were to be used as emergency lights in case of a power cut or some other disaster.

[Phantaxus]

http://www.howstuffworks.com/light-stick.htm/printable

[Hamish]

In some chemiscal reactions excess energy realsed leaves as heat, if there is lots you get an explosion. The reaction in the tube produces light rather than heat and is called cold light.