Depth 1 · 67 s
Through the clouds
A cool, grey day at the beach, and sore pink shoulders by evening. Why invisible UV light gets through cloud, what the UV index tells you, and the order to protect yourself in, shade and clothes before sunscreen.
About this video
A grey, cool day at the beach. Nobody feels hot, so nobody bothers with a hat, and by evening everyone's nose and shoulders are pink and sore. Sunlight carries more than the light we see: part of it is UV (ultraviolet) light, which is invisible. UV damages the DNA in skin cells, the instructions each cell carries. A sunburn is a sign of that damage, and the damage adds up over the years. The World Health Organization (WHO) says skin cancers are caused mainly by UV, from the sun and sunbeds, and that sunburns in childhood raise the risk of skin cancer later in life. UV can harm the eyes too.
Clouds don't stop all UV: thin cloud hardly changes it, and the NHS says you can burn even when it's cloudy. A cool day only means less heat, not less UV.
Weather apps often give a UV index, a number for how strong the UV is that day. WHO says to protect yourself when it is 3 or more, and UV is strongest in the hours around midday.
WHO says the best protection is shade and clothes, not sunscreen. So: shade, especially around midday; clothes and a wide-brimmed hat; sunglasses that block UV; and sunscreen for the skin clothes can't cover, SPF 30 or more, put on generously and again about every 2 hours and straight after swimming. Sunscreen is not a reason to stay out longer.
People of every skin colour can burn and get skin cancer. Sunbeds raise the risk of skin cancer and should never be used to get vitamin D. Your skin does need some sun to make vitamin D, but a little is enough, and you cannot overdose on vitamin D from sunlight. This video goes with the lesson Sun and Skin in Health Level 1 on Knaph.
This video shows depth 1 of Sun protection.
Learn Sun protectionTranscript
- 0:00A grey, cool day at the beach. Nobody wears a hat. By evening, noses and shoulders are pink and sore. How?
- 0:09Sunlight carries UV, light you can't see, and thin cloud hardly stops it. It damages skin cells, and the damage adds up. Sunburn in childhood raises the risk of skin cancer later.
- 0:22Weather apps give a UV index. At three or more, protect yourself. The higher the number, the faster skin is harmed, and UV is strongest around midday.
- 0:33Shade and clothes come first. Then a hat and sunglasses. Then sunscreen, SPF thirty or more, again every two hours and after swimming. And sunscreen is not a reason to stay out longer.
- 0:48Every skin colour can burn. Sunbeds give out UV too, so never use them. And a little sun is enough for vitamin D.
- 1:00A cool day only means less heat, not less UV.