physics

[andys15]

how come black surfaces can absorb the suns heat ,but white surfaces can retract the heat

[moonacre]

Heat is very close on the electromagnetic spectrum to visible light but our eyes can't see it. If something is white it is because it is reflecting visible light back to your eyes. If it is black then it isn't reflecting light but absorbing it so the light isn't reflected back to your eyes. If something can reflect or absorb visible light it can also reflect/absorb heat in the same way.

[Nellie2]

It is to do with WHAT white, black and light is. Light is the spectrum of colours. (the rainbow) White is all colours combined. That is, if you were to combine all the colours of the spectrum in equal portions, you would get white. (Think of it as a full glass of water.... with the water being the light) Black is "colourless". That is, black is what results when you remove any and all colours of the spectrum. (An empty glass) So.... Black absorbs light because it is "colourless"... it has no colour therefore it is able to absorb colour. (The empty glass can be filled) White, reflects light because it already has all the colours (the glass is already full). Hope this helps some. P.S. This is why dark colours "fade". They lighten in colour as they absorb light. A black piece of cardboard, if left long enough in full sunlight, would eventually become white.

[andys15]

thank you very much it has helped me to understand it a lot more. thank you