Barns are painted red because of the physics of dying stars
Barns are painted red because of the physics of dying stars Fall colors frame a red barn in East Montpelier, Vt. (AP Photo/Toby Talbot/AP Photo/Michael Felberbaum)
Barns are painted red because of the physics of dying stars
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Have you ever noticed that almost every barn you have ever seen is red? There's a reason for that, and it has to do with the chemistry of dying stars. Seriously.
Yonatan Zunger is a Google employee who explained this phenomenon on Google+. The simple answer to why barns are painted red is because red paint is cheap. The cheapest paint there is, in fact. But the reason it's so cheap? Well, that's the interesting part.
Red ochre is also known as Fe2O3. It is a simple compound of iron and oxygen that absorbs yellow, green and blue light and appears red. It's what makes red paint red and it's really cheap because it's really plentiful. And it's really plentiful because of nuclear fusion in dying stars.
Zunger explains:
The only thing holding the star up was the energy of the fusion reactions, so as power levels go down, the star starts to shrink. As it shrinks, the pressure goes up, and the temperature goes up, until suddenly it hits a temperature where a new reaction can get started. 

These new reactions give it a big burst of energy, but start to form heavier elements still. And so the cycle gradually repeats, with the star reacting further and further up the periodic table, producing more and more heavy elements as it goes. Until it hits 56. At that point, the reactions simply stop producing energy at all. The star shuts down and collapses without stopping.
As soon as the star hits the 56 nucleon (total number of protons and neutrons in the nucleus) cutoff, it falls apart. It doesn't make anything heavier than 56.
What does this have to do with red paint? Because the star stops at 56, it winds up making a ton of things with 56 nucleons. It makes more 56 nucleons containing things than anything else. That is aside from the super light stuff in the star that is too light to fuse.
What element has 56 protons and neutrons in its nucleus in its stable state? Iron. The stuff that makes red paint.
And that, Zunger explains, is how the death of a star determines what color barns are painted.

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Why would farmers choose the least expensive paint for their barns?
Write your answers in the comments section below

  • joeyh-
    4/24/2017 - 08:34 a.m.

    Barns tend to get beat up and aren't all too difficult to build. Why would a farmer want to waste money on the color of something that is only going to get old and rot away?

  • Nikolaij
    4/24/2017 - 08:38 a.m.

    save money

    • aleahs-kul
      4/24/2017 - 12:29 p.m.

      I agree, I have not thought about why they are red either. I thought maybe because that was the history of them, being red. I figured it was a monkey-see-monkey-do thing, where one farmer paints it red so the others do as well.(43 words)

    • danielb-kul
      4/24/2017 - 01:03 p.m.

      I agree with Carson because I don't think farmers think about it that much. They probably just do it because it is cheaper and plentiful.

    • dylann-kul
      4/24/2017 - 01:04 p.m.

      I agree with Carson Simes. I thought that they were red just because thats how the farmer wanted it. I didnt actually realize there was a legit reason.

    • matthewm-kul
      4/24/2017 - 01:06 p.m.

      I agree with Carson because it doesn't make any sense at all how dying stars can be related to the price of red paint.

    • bethanyl-kul
      4/24/2017 - 01:07 p.m.

      I agree, I think it is very interesting how scientists took two completely unrelated things and connect them. However, I don't know if i think this is the real reason why barns are red.

    • jennav-kul
      4/24/2017 - 01:08 p.m.

      I agree, I have really never thought about it that much. I don't think its the reason barns are red either. I just think because it was the cheapest.

    • adrianna-kul
      4/24/2017 - 03:43 p.m.

      I agree. I kind of just thought that the red paint was a traditional color to use for farmers.I wouldn't have ever guessed that the color had something to do with the stars and that the color could help revive them.

  • luisa-kul
    4/24/2017 - 10:21 a.m.

    I think is amazing how a star that is dying far away in the space can affect the life of a farmer, I did know that red paint is cheaper than other color of paint, that is why I found reasonable that the farmers paint their barns with red paint.

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