A scorching summer fair

Last weekend I ran a science stall at my daughter’s school summer fair. I would love for kids to think it normal to take part in fun science activities as well as win sweets and eat cakes!

The beads inside (no UV light)

This year, I had UV-sensitive beads for visitors to make into wrist-bands or bag charms. The beads change colour under UV light. It was a scorcher of a day so ideal for demonstrating the beads.

Light is made up of colours we can see (the colours of the rainbow) and some which we can’t (e.g. ultra-violet or UV light). These beads change colour in UV light. Inside they are clear as seen in the picture to the right.

Take them outside (or shine a UV light on them) and they change colour. Even on a cloudy day they change faintly. On a really sunny day the colours are bright as can be seen in the second picture below.

…and outside in bright sunlight

Too much UV light from the sun can give us sunburn and damage our skin. We used factor 30 sun cream to block the UV rays and prevent the beads from changing colour.