Tuesday, 23 July 2019


I've been trawling the archive having a look at old SUMMER SCIENCE SNIPPETS to see what can be updated and what is just so good it is worth sharing again! So over the next few weeks while UK schools are closed I will be sharing some old and some new and some tweaked Science Snippets. Here is an updated one first shared in 2015!


Depending where you live you may have had a decent amount of sun or very little at all this summer so you might be thinking that it is an umbrella you need not sunscreen but UV can damage our skin even on a cloudy day so the science of sunscreen is always worth another look.

When choosing sunscreen you need to look for one that includes UVA and UVB protection - UVA penetrates deeper into dermis giving the deeper damage - ageing, wrinkles and some skin cancers whereas UVB is the redness and sunburn and can also contribute to skin cancer.
There are creams, gels and sprays on the market that only need applying once a day even if you go swimming and you can get very high factors beyond 50 for fair skins, sensitive skins and the very young. Plus don't forget if you are taking medication or pregnant that can have an effect on your sensitivity. 
Apply liberally - and it really does means that - you need to make sure that you have covered your skin and all those easy to miss spots like the top of your feet!

special UVA filters on the camera show the effect of wearing sunscreen

There are some fun creams for youngsters that go on in neon colours so you can see where you have applied and the kids think it is cool. 

There are also some great gels around for sporty folk who will get sweaty and for the more hairy who hate putting heavy creams on.

You can now get clothes, flip flops, hair bobbles and wrist bands that change colour in UV and give you an idea about exposure.

Over the years we have used our UV beads many times and always everyone is so surprised at how reactive they are even in weak sunlight.

If you haven't seen them before they are little creamy coloured beads that turn brightly coloured when exposed to UV.
We often use them in investigations to test whether the different factors of sunscreen make a difference. I have seen them made into scrunchies for hair, tied on flip flops and even sewn onto baby clothing. I think many people are not aware how UV can bounce around even when you think you are in the shade.
The images here speak for themselves.
You can see the beads exposed to full sunlight at the top of each bag and then one bag is smeared with Factor 20 and the other Factor 30. The F20 beads are quite noticeably darker than the F30.

The very first time we did this I made the mistake of smearing the sunscreen onto the beads themselves and it took me forever to get it all off! So now we use a plastic bag smeared with sunscreen to show the effect .
You can also use the beads to show how sunglasses protect your eyes ( or not) from UV but that is for another post!

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