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.

Filed Under:  
Assigned 224 times
CRITICAL THINKING QUESTION
Why would farmers choose the least expensive paint for their barns?
Write your answers in the comments section below


COMMENTS (33)
  • samanthas-1-ste
    4/20/2017 - 01:31 p.m.

    The choose the least expensive paint because it will come off or fade after awhile. they dont want to have to keep repainting over and over.

  • 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.

  • 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.

  • chriss2-ver
    4/21/2017 - 09:12 a.m.

    That's really interesting, I would of never thought of a star being the cause of the color of a barn. I also thought it was kinda interesting that red paint is th cheapest paint you can buy. My only question is did people know this when they were panting the barns?

  • hayleel-ste
    4/21/2017 - 12:50 p.m.

    This is cool I never knew why almost every barn I saw was painted red, well now I know. Although I never thought a star would be the cause of the color of the barns.

  • brooket1-ver
    4/21/2017 - 03:15 p.m.

    I never knew the reason barns were red. I always thought it was because red paint is cheap and now I know why it is cheap. It's weird to think that something so simple like a red barn can be connected to something so far away like the death of a star.

  • jordanb2-ver
    4/21/2017 - 03:15 p.m.

    if its bright red or cheap it suits the barn

  • jasmina-bur
    4/23/2017 - 08:44 p.m.

    Farmers might want the least expensive paint for their barnes so they can have money to buy other things that they need. Sometimes, farming can be expensive. If I were a farmer and my barn needed a fresh coat, I would most definitely go the cheapest route to insure that my farm is financially ready for a future.

    • 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.

Take the Quiz Leave a comment
ADVERTISEMENT