Disappearing Foam Cup

This is looks like a chemical reaction but it’s not – it’s really just a physical change. It’s a really neat trick you can do for your friends or in a magic show. Here’s how it works:

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10 Responses to “Disappearing Foam Cup”
  1. Aurora says:

    Oops – sorry about that? I”ll have my team fix it right away.

  2. Aurora says:

    I apologize for the trouble. If you’re going through the program by grade level, simply contact us with the grade level you need and we’ll unlock everything you need for that level. We’re working to get this resolved so you’ll have access to everything you need, so in the meantime this is our “work around”. I’ll have Tonya bet in touch to make sure you have everything you need.

  3. Klbelemjian says:

    This experiment is classified as 5th grade science, but I can’t access it because the page says 9-12th grade. That’s a tease. Please give access to K-8 members or remove it from 5th grade science category.

  4. Aurora says:

    It may work… try it!

  5. Marcelene Ryan says:

    This experiment is very interesting looking we have styrofoam cups but no acetone. Is it possible just to use regular nail polish remover?

    Thanks: Channing Ryan 🙂

  6. Aurora says:

    When polystyrene dissolves in the acetone, the air that is inside the foam is released just like adding sugar to hot water. Polystyrene is mostly air, which makes this experiment really dramatic. Acetone (CH3)2CO has a high degree of solvency, meaning that many compounds are soluble when exposed to it.

    Polystyrene is made of long chains of styrene molecules which are normally hard and rigid (like in hard plastic bottles), but when a gas is bubbled through it to make Styrofoam, it turns foamy and compressible (like a coffee cup). It’s the same stuff, just processed differently to give it different properties.

    Styrofoam is soluble in acetone, but not in other liquids like water because of acetone’s solvent properties. When placed in acetone, the acetone serves as a molecular lubricant between the polymer chains, causing them to slide past each other, making the Styrofoam soft and releasing the air bubbles that were trapped in the foam. If you pull it out of the acetone, it will solidify into a hard piece of plastic.

    The Styrofoam molecules are still present in the solution, which allows recycling manufacturers methods of extracting polystyrene and reusing it for new materials. It s a physical change because it’s a simple dissolving process that collapses the matrix.

  7. Robin Wu says:

    When acetone dissolves the bonds between these long polymer chains- according to the worksheet accompanying the disappearing foam cup:

    “What to Learn: You should understand that Styrofoam is made mostly of air and a polymer called polystyrene.
    When acetone dissolves the bonds between these long polymer chains, the air is released and voilà, you have a
    polystyrene puddle.”

    So breaking up bonds of polymers does not equate to breaking up bonds in a molecule- that the former bond breaking could result in physical change whereas the latter bond breaking results in chemical change?

  8. Robin Wu says:

    How are the air released from the polysteryene molecule without breaking any bonds (which I read elsewhere is part of chemical change)?

  9. Aurora says:

    There are a couple of easy to find materials that are not included because they are considered hazardous to ship (and would make the price of the kit skyrocket), and acetone is one of them (hydrogen peroxide and rubbing alcohol are the others). You can easily find these in the hardware or drug store in your town.

  10. Tara Chapman says:

    Does acetone come in the kit that is automatically sent I’ve searched all the kit

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