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
Lexile

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


COMMENTS (109)
  • polivia-dav
    4/20/2017 - 12:14 p.m.


    In response to this article titled, "Barns are painted red because of the physics of dying stars," I learned many facts. I never knew barns were always painted red because of stars. In the article, it says, "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. At first when I read that sentence, I wondered why painters couldn't use other paints as oppsed to red. But then I went on to read that it makes red ochre very plentiful. In the article it states, "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." I have always assumed barns were painted red for no reason. It is good to learn all of the science behind this. I bet not a lot of people have heard about this so I am happy that I know it now.

  • genesisj-
    4/20/2017 - 01:06 p.m.

    They use the less expensive because of chemsitry due to the fusion of the dying stars...

  • rileys4-har
    4/20/2017 - 02:53 p.m.

    Farmers choose the least expensive paint for their barns because in this article it states, “It’s what makes red paint red and it’s really cheap because it’s really plentiful.” This quote is telling the readers why it’s so cheap. It’s plentiful because of the nuclear fusion in the dying star. It is also so cheap because of the stuff that makes the red paint also. That is why most farmers choose the least expensive paint.

    • rileyn-kul
      4/28/2017 - 12:52 p.m.

      I think farmers need to save money where they can such as on paint. Nevertheless this is outdated because nobody builds barns out of wood and paints them red anymore.

    • rileyn-kul
      4/28/2017 - 12:54 p.m.

      Farmers need to save money where they can, especially in tough markets and times. It is important to save money where you can. Sometimes in tough markets its easiest to expand because for instance you can buy heifers cheap and breed them and in a few years they may be worth a lot. In order to have all those cows you must build a barn when you don't have a lot of money so you have to save as much money as possible.

  • pshea-dav
    4/20/2017 - 03:42 p.m.

    In response to "Barns are painted red because of the physics of dying star," I agree that barns are painted red because of dying star. One reason I agree is that red is the most cheapest paint colo.Another reason stars have 56 protons and neutrons when it's in a stable state and iron has 56 nuetrons and protons which make red . Even though it's very silly thought , I think it actually makes sense

  • bchase-dav
    4/20/2017 - 04:50 p.m.

    In response to "Barns are painted red because of the physics of dying stars," I agree that painting bars red is good. One reason I agree is that red looks nice in my opinion. Another reason is that the materials used to make it are plentiful. It says in the article "Iron is very common". A third reason is that it would cost less money in the long run.
    It may cost only a couple cents less, after repainting a bunch, you could save $10. Even though some people may not like the color red, I think that painting bars red is good.

  • graceb2-har
    4/20/2017 - 06:25 p.m.

    Farmers choose the least expensive paint for their barns because they want to save money, especially since they are having to buy food and other needs for their barn animals. In fact, red paint is the cheapest color paint, so that explains why most barns are red.

  • wjake-dav
    4/20/2017 - 07:46 p.m.

    I think red is a good color to paint a barn because one it is cheap. "because red paint is cheap." Another reason red is a good color is because red paint is mostly made of iron and the stars burst when it get to iron."What element has 56 protons and neutrons in its nucleus in its stable state? Iron. The stuff that makes red paint." That is why red is a good color for a barn.

  • smattison-dav
    4/21/2017 - 07:39 a.m.

    The people would want something that would last for a while. Even if it were to fade you could still see it. It is not that expensive because there is alot of iron. There could be ways that we could create some paint that would last longer than are normal paint. We wouldn't need to paint it for years.

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