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Home / Science projects / Quick Crystal Cup
  • Quick Crystal Cup

    Quick Crystal Cup

    Growing crystals can take several days, but this super-easy recipe gives you a cup full of needle-like crystals in just a few hours!

    What You Need:

    What You Do:

    1. In the beaker, stir 1/2 cup of Epsom salts with 1/2 cup of very hot tap water for at least one minute. This creates a saturated solution, meaning no more salt can dissolve in the water. (Some undissolved crystals will be at the bottom of the glass.)
    2. Add a couple drops of food coloring if you want your crystals to be colored.
    3. Put the beaker in the refrigerator.
    4. Check on it in a few hours to see a beaker full of crystals! Pour off the remaining solution to examine them.

    What Happened:

    Epsom salt is another name for the chemical magnesium sulfate. The temperature of the water determines how much magnesium sulfate it can hold; it will dissolve more when it is hotter. Cooling the solution rapidly encourages fast crystal growth, since there is less room for the dissolved salt in the cooler, denser solution. As the solution cools, the magnesium sulfate atoms run into each other and join together in a crystal structure. Crystals grown this way will be small, thin, and numerous. Left undisturbed, the crystals should last months or more! 

    To grow large single crystals, you'll need to follow the evaporation procedure in this project.

    Buy Quick Crystal Cup Experiment Kit

    testing for starch kit

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By: Ava
Date: Oct 26, 2015

Amazing ⭐️⭐️⭐️⭐️⭐️

By: Bryant Merritt
Date: Oct 21, 2015

I like this project and I have a science Fair project

By: jakayla wade
Date: Oct 08, 2015

its awesome

By: Kim
Date: Sep 29, 2015

I made these crystals and dropped a sea shell in the solution. Turned out beautifully!....and that was 2 years ago! Still look great in my windowsill.

By: paige
Date: Sep 20, 2015

my crystals were like it was in the picture,  then, after a few minutes, it turned to slush!

By: Sarah
Date: Jul 22, 2015

Hi there! I am a third year Fine Arts student and my prac work for this semester is focused on the growth of minerals and time in relation to decay of organic materials/objects. I plan to grow various crystals onto objects, and want relatively quick results, which I assumed would be possible with crystals made from Epsom salts.  I followed similar instructions on another site but the crystals still haven’t formed yet and I made the solution yesterday afternoon and its still in the fridge. I bought the Epsom salt from a pharmacy, but maybe they were the wrong ones? Any advice you could give me on how to make this work (I don’t know why mine didn’t because it seems pretty pain free) and also if you know whether I could grow these crystals onto an object submerged in the solution?

[HST Adds:  Epsom salts from any source should work the same as long as there are no additives.  The temperature of the water you use can affect the rate of growth.  You may wish to try heating your solution gently and see if you can dissolve more salts into it.  The water should be hot but not boiling.  It is possible to grow crystals on a submersed object, and it may even work as a catalyst to get your crystals to start growing faster.  Your crystals will be very delicate, so keep in mind the size of the submersed object and the opening of your container.  Hope this helps!]

By: looool
Date: Jun 22, 2015


By: adaeshia
Date: Jun 08, 2015

thank you for your helpful ideas

By: Karen
Date: Jun 03, 2015

My won made this for a science project. How long will the crystals last after being removed from the refrigerator?
I need answer ASAP


By: toe_gurl
Date: May 12, 2015

i didnt enjoy this very much but my 24 son did! he is such a child! it did look very cool though. !!

but i was wondering how long do the crystals last??

thanks again for the wonderfull idea!!!!!!!!!!!!!!!!!!!! bye now x