Would wearing mirrors keep me cooler in the sun?

The short answer is yes.

Mirrors are very efficient at reflecting sunlight. When sunlight reaches the surface of the Earth, over half of its energy is heat, so a mirror placed in the way of your body will do a good job at reflecting most of that heat.

But glass is not necessarily the most practical material to be making clothing from: it’s not very flexible and can cause irritation to our skin.

Clothes made from white textiles, while less efficient than mirrors, will reflect more sunlight than darker clothes. This will keep you relatively cooler and it’s why cricketers wear whites!

And Stanford University’s Shanhui Fan has produced a special brand of silk to mitigate the effect of ultraviolet radiation from sunlight warming up this comfy clothing material. Here he is speaking to us a few years ago about his work...

'Native silk absorbs ultraviolet light absorption of ultraviolet light gives rise to heating of the textile. We introduced aluminium oxide nanoparticles into the silk. A nanoparticle just looks like a little ball, except they are very, very small. The nanoparticle that we put in is designed so that it reflects strongly the ultraviolet light.'

And Professor Fan has proven the effectiveness of his special silk:

'We have demonstrated is that nano-processed silk when placed under direct sunlight by itself can reach a temperature that is 3.5 degrees Celsius below ambient and therefore a person wearing such a nano-processed silk in an outdoor setting is essentially wearing his own air conditioning.'

Not bad, eh? The nanoparticles are locked tightly in the silk with the use of a chemical bonding agent, meaning they don’t come out in the wash.

So, Lotus, yes, mirrors might keep you cool out in the sun, but there are perhaps more practical solutions out there, aside from seeking shade and drinking lots of water of course, in the form of white clothing and nano-processed silk.