know how to stay safe in the sun (understand UV light)
Schweppes Tonic water
Two index cards
Unltra violet Light or UV light is the part of sunlight that can cause damage to our skin. It is not visible to the naked eye, but we can illustrate its presence in this experiment.
• On one index card write ‘Tap’ and on the other ‘Tonic’.
• Stick these to the black card.
• Fill each glass to the brim with its liquid and place in front of the black card.
• Shine the torch on the two glasses and see can you see any difference.
• Now bring all the items outside and sit them in the sun – can you see the difference in the colours now
The tonic water appears blue. This is because the quinine in tonic water is sensitive to UV light and absorbs it – it then emits it as blue light, which we can see. This is called fluorescence. Use this example to explain that just beacsue we can't see UV rays , doesn't mean they don't exist and they can cause damage without us realising it.