The sun's rays

graphic of city beside a river and mountains;

Select four interesting facts about UV rays from the facts listed below.
Choose one UVA, one UVB and one UVC fact as well as one general UV fact.
Compare the facts you chose with those selected by other students in your class.

	UV rays cannot be seen or felt. They are not related to temperature.
	UV radiation is present even when the temperature is low.
	UV radiation is highly reflective so, not only does it reach you directly from above, it scatters and reflects off water, sand, snow and many surfaces.
	The time of day, time of year, geographical location, including latitude and altitude and cloud cover all affect the UV radiation levels.
	UV radiation can penetrate clouds.
	If the UV index is 3 or above, sun protection is needed as skin damage can occur.
	Skin ageing and wrinkling can be caused by UVA rays.
	Eye damage and therefore vision problems can be caused by UVA rays.
	Reactions in the skin can be caused by UVA rays.
	UVB rays are reduced by nearly all sunscreens according to their Sun Protection Factor (SPF).
	Direct DNA damage which can lead to cancerous growths can be caused by UVB rays.
	Sunburn through overexposure can be caused by UVB rays.
	UVB rays are needed in appropriate amounts to produce vitamin D for healthy bones ... about 10 minutes a day in summer through to 30 minutes a day in winter, but outside peak UV times.
	The body is helped to produce melanin, the brown skin pigment known as a suntan, by UVB rays.
	The ozone layer in the atmosphere stops and absorbs UVC rays.