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Light coloured objects are light coloured because they are reflecting most of the photons that hit them back to your eyes. Dark coloured objects are dark becaus
by goodcanadian 8y ago
Light coloured objects are light coloured because they are reflecting most of the photons that hit them back to your eyes. Dark coloured objects are dark because they are absorbing more of the photons. This is why dark coloured objects heat up faster in the sun; they are absorbing more photons. However, generally, the converse is also true, objects that readily absorb photons also readily emit them. So, the dark object will cool down more rapidly in the shade or at night. The wavelength (or colour) emitted depends on the temperature of the object. At room temperature, the emission peaks in the infrared, so the object still appears dark (but will glow brightly in night vision goggles). As it gets hotter, the peak emission moves into the visible spectrum and the object starts to glow (red hot then white hot).
- benj111 8y agoI have a nice nerd snipe. Is it better for the inside of a fridge to be black or white? Discuss.
- yxhuvud 8y agoWhite, because it allows you to clean it effectively.
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- Dylan16807 8y agoI don't understand what you think there is to ponder deeply here. A fridge body is a pure insulator so the answer has to be white. Also it barely matters because convection will cool the surface anyway. Super straightforward with no math to do or conflict to resolve, unless I'm missing something.
- abakker 8y agoAs long as the door opens vertically (vs being the lid on a trunk like a deep freezer) it doesn’t much matter. Refrigerators really need to recover cold air more than focus on absolute perfect insulation. I’ve always thought that we should just all move to the refrigerator-as-a-bunch-of-independent-drawers design. I think it would be easier to browse efficiently and easier to design a kitchen around.
- sitkack 8y agoMy neighbor has this, built directly into the cabinets. Just cold drawers, blew my mind.
- kwhitefoot 8y agoIKEA used to sell fridges that were drawers builtin to kitchen units.
- Zenst 8y agoFor insulation, lighting. Key aspect is that the cooling element in a fridge is seperate from the white insulation and is often raw metal. Now, if you look at the back of the fridge where is expels/radiates the heat - that is black. For me, I've often thought that heat could be utilised. Be is pre warming up water designated for hot water use (which would also aid in cooling fridge and increase its efficiency and life expectancy as well). Or some peltier/sterling type energy recovery. But good question and in the same spirit: Why is thermal paste and pads white?
- hollerith 8y agoThermal paste isn't designed to radiate heat -- it is intended to conduct it -- so its being black wouldn't make it more effective.
- AceyMan 8y ago> For me, I've often thought that heat could be utilised. It's a specific use case, but this exhaust heat is very useful. Use the top side of the refrigerator as a delicate drier for damp things that cannot be tumble dried. Soggy umbrellas. Leather gloves (even shoes). Hats made sweaty from work or exercise. Put them on the top of the fridge overnight and IME by morning they are just about perfectly dried out.
- bacon_waffle 8y agoUm, it just happens that I'm sitting behind a brand new fridge (not as awkward as it sounds, this old house doesn't have cabinetry for the fridge yet). It's white.
- Zenst 8y agoThat's unusual - as in never seen one that's not black. Wonder why - aesthetics perhaps.
- bacon_waffle 8y agoI don't think it is unusual at all to be honest; the one this fridge replaced was also white, and the neither seems to have a back that is intended to be looked at - there are plenty exposed seams, plumbing, the compressor. Offhand, it doesn't seem like there would be much thermodynamic advantage in the heated surfaces of a fridge being black. If there were, wouldn't you expect that car radiators and such would be black anodised too? I'd imagine conduction is going to be a much much bigger effect than radiation - other concerns like cost, durability, thermal conductivity of the paint, and aesthetics will likely be more important in deciding what colour paint to use.
- the8472 8y agoOn the inside, even for the cooling elements, it should be irrelevant since the planckian locus at 300k is outside the visible spectrum. The importance of the albedo in the far infrared also depends whether most heat transfer in a fridge is convective or radiative.
- RHSeeger 8y agoI like to joke with my daughter that her red shirt is every color BUT red, because that's the only color it doesn't keep.
- Zenst 8y agoEqually it is a good angle in handling racist mentalities, and you get to ask them why do they hate themselves. Science is a wonderful gift in any debate.