STEM Clubs

School: Hanham High School Status: In progress Date Started: 25 Nov 2009 Date Completed: 19 Nov 2013 Keywords tags: luminol hydrogen peroxide chemiluminescence Physics Energy Chemistry No of pupils: 11 Number of views: 318

Students experimented with different coloured glow sticks measuring the amount of light given off and the duration of the chemiluminescence.

Glow sticks are used extensively as safety devices in situations where the need to be seen is important and reliability is required, i.e. batteries that can leak or go flat when stored in exposed or difficult conditions cannot match the durability of two chemicals stored in robust plastic containers with "shelf lives" of many years. They are, of course, more commonly seen at music festivals and fairgrounds where they are sold as safe and cheap alternatives to open heat sources (sparklers) or electronic devices.

Pupils used small hacksaws to carefully cut the sealed tops from Gelert Glow Sticks (available at most campling shops) of various colours. The plastic capsule contents were decanted to beakers whilst retaining the inner glass container. Breaking the ends off the glass container was completed using pliers whilst the container was held within a cotton wrap to prevent glass cuts.

After their mixing experiments pupils made several observations. The most interesting being that the external walls of the glass beakers used for mixing acted like "optical fibres" since the light could clearly be seen more strongly at the beakers tops edges (see the pictures). Pupils also noted that the pictures they took were so well illuminated by the light being given off that the camera did not need a flash even though the room was darkness!