This salt crystals science project is a fun and easy science experiment for kids, perfect for home or school.   Grow your own salt crystals with just a few simple ingredients and watch the AMAZING crystals grow overnight for simple science any rock hound or science enthusiast will love!


How to grow salt crystals Easter science activity for kids and easy chemistry experiment.Pin


Every time we grow a new batch of crystals, whether they are salt crystals or borax crystals, we are always amazed by how cool this type of science experiment is to do! Not to mention how easy it is as well!

There are a few ways you can explore how to make crystals that we are starting to experiment with more and more this year. We have always grown the traditional borax crystals on pipe cleaners type, but we are having fun with learning how to grow salt crystals too.

Here we went with an Easter egg theme for our salt crystals. But you could use paper cutouts of any shape.

Salt Crystals Easter Science ActivityPin


I have noticed that young kids do very well with repetition, but repetition doesn’t have to be boring. We love to share hands-on science activities that are always fun and exciting but also repeat the same concepts to develop understanding for young learners.

That’s where theme science activities come in to play! We have now done a bunch of different holiday themed salt crystals activities like snowflakes, hearts, and gingerbread men. Doing it this way gives us more chances to practice what we have already learnt but with variety!



To make salt crystals you start with a supersaturated solution of salt and water. A supersaturated solution is a mixture that can’t hold any more particles. Like with the salt here, we have filled all the space in the water with salt and the rest is left behind.

Water molecules are close together in cold water, but when you heat the water up, the molecules spread away from each other. This is what allows you to dissolve more salt in the water than you normally could. It even appears cloudy.

You can try this experiment with cold water to compare the differences in the amount of salt needed to get this mixture, and you can compare the results of the crystals afterward.

So how do the salt crystals grow? As the solution cools the water molecules start to come back together, the particles of salt in the solution fall out of place and onto the paper. More will connect with the molecules that have already fallen out of the solution.

As the salt solution cools and the water evaporates, the atoms (niacin and chlorine) are no longer separated by water molecules. They begin to bond together and then bond further forming the special cube-shaped crystal for salt.

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Learning how to grow salt crystals can be a great alternative to growing borax crystals for young kids who may still be into tasting their science activities. It also allows them to be much more hands-on and participate in the set up of the activity. 


  • Construction Paper
  • Water
  • Salt
  • Container and Spoon {for mixing salt solution}
  • Tray or Plate
  • Egg Shape {for tracing}, Scissors, Pencil
  • Hole Puncher and String {optional if you want to hang them when you are finished}


STEP 1:  Start by making as many cut out shapes as you would like. Or you can just make one giant shape if you prefer that fills your tray. You will want the shapes to lay as flat as possible, so we used a cookie tray.

At this point, go ahead and punch a hole in the top of the paper cutouts if you plan to use your salt crystals as an ornament!

STEP 2:  Place your cutouts on your tray, and get ready to mix your super saturated solution (see below).

STEP 3. First you need to start with hot water, so this is an adult only step if needed.

We microwaved about 2 cups of water for 2 minutes. Though you can see from the above right photo, we did not use all of our solution for our tray.

STEP 4. Now, it’s time to add the salt. We added one tablespoon at a time, stirring very well until completely dissolved. You can feel the point at which it’s not gritty as you stir. {Close to 6 tablespoons for us}

Do this with each tablespoon until you can’t get rid of that gritty feeling. You will see a bit of salt on the bottom of the container. This is your super saturated solution!

STEP 5. BEFORE you pour the solution onto your paper shapes, move your tray to a quiet location that won’t be disturbed. It’s easier than trying to do it after you have added the liquid. We know!

Go ahead and pour your mixture over the paper just covering them with a thin layer of the solution.

The more solution you pour over, the longer it will take for the water to evaporate!

You can see that our egg cutouts had a bit of a tough time staying separated and we didn’t try to fix it too much. You could experiment with different methods like tape to stick them down first or an object to block their movement.

Now you just need to give it time to form the salt crystals. We set this up mid-morning and started seeing results by late evening and definitely the next day. Plan to allow approximately 3 days for this activity. Once the water has evaporated, they will be ready.

Borax Crystals are ready faster if you need a quicker crystal growing activity!!


In order to make the best crystals, the solution has to cool slowly. This allows any impurities that are also caught up in the solution to be rejected by the forming crystals. Remember the crystal molecules are all the same and are looking for more of the same!

If the water cools too quickly the impurities are trapped creating an unstable, misshapen crystal. You can see that here when we tried to use different containers for our borax crystals. One container cooled slowly and one container cooled quickly.

We transferred our salt crystal covered egg cutouts to paper towels and let them dry out for a while.  Plus, the crystals really seem to bond nicely as everything dries out more.

When they are nice and dry, add a string if you wish. Examine the salt crystals with a magnifying glass too. You can explore one single crystal as well like we did below.

These crystals are so cool and they will always be cubed shaped whether they are by themselves or in a cluster. This is because a crystal is made of molecules that come together in a repeating pattern. Check out our single crystal above!


This salt crystals experiment would make an easy science fair project.  You could experiment with different water temperatures, different trays or plates, or covering the crystals slightly to minimize heat loss.

You could also vary the type of salt used.  What happens to drying time or crystal formation if you use rock salt or Epsom salt?

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  1. I am having trouble growing the crystals, is it possible that I am heating the water up too much? After a few days very little of the water has evaporated and no crystals have formed.

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