The Appliance of Science: Albedo Rates And How They Can Help You

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The albedo rate is not something that comes up in conversation very often but it can be very useful to understand what it is and how you can make it work for you in a variety of situations.

Put very simply it is the rate of absorption of heat by a particular material. Now that may sound like something that belongs in a lab, but when you see the difference in absorbed heat in for example bare rock and rock covered in ice you will see how this can be applied to the colours of materials as well as to the materials themselves.

Scientists use the albedo rate to work out how much heat is reflected back into the air from glaciers. The compare this to the rate heat is absorbed by the darker rock elsewhere on the glacier and therefore how fast that glacier will melt.

Doesn’t seem like albedo has much to do with our everyday lives does it? Wait though, what makes you decide to wear light coloured clothing in summer and darker clothing in winter? Albedo that’s what.

You know that the lighter shirt will keep you cooler so that’s the choice you make for hot weather. The reason it keeps you cooler is simple, more heat is selected back from its surface than would be selected back if you wore a black shirt. your common sense choice is actually the appliance of science!

Now sometimes things get a little skewed, like why are pool covers made of a silver coloured fabric that reflects heat away rather than a dark colour that will draw heat into the water underneath.?Well, this is a commercial thing, the manufactures down want algae growing and you to think that their pools are worse than their competitors for algae growth so they reflect sunlight, and therefore heat back away from the cover. that expensive solar cover you purchased is worthless for heat retention!! way better and cheaper to treat the water in your pool, fish out grass and other debris and float black heavy duty garbage bags on the surface at night and leave them there until you want to use it the next day. As soon as the sun comes up the black bags will draw in the heat and make the pool a little warmer.

You can use the same principle for windows. A light coloured lining will reflect heat away from your windows, a dark one will draw heat in.

Whilst this principle works best on solid objects such as brink and tile we know from the clothing example that it applies to fabrics as well, albeit with a lesser degree of change. Got a garden room or conservatory that’s freezing in winter? Put a curtain pole along the back wall and hang dark curtains from it in winter to pull in more heat from the winter sunshine outside. Draw them back to reveal the light coloured wall in summer, or vice-versa. The same applies to rugs in such a room, a light one for summer and a dark one for winter.

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Check it out yourself, put two pieces of card one black and one white, in the sun. Take the temperature at the start and then every five minutes for fifteen minutes. the black card will be several degrees higher than the white card.

Making the albedo rate work for you can cut your fuel bills and in a situation where we are relying on the sun for heat every degree will count. still need convincing? Ask yourself why solar panels are dark coloured…

Take care

Liz