sea salt crystal experiment

Science Fun

Salt Crystals Science Experiment

In this fun and easy crystal science experiment, we’re going to grow salt crystals.  

Note: Since hot water in involved, please insure adult supervision is utilized.

• Piece of string

Instructions:

• Fill the jar with hot water.
• Slowly stir in several tablespoons of salt.
• Tie one end of the string around the nail.
• Next tie the other end of the string around the pencil in a way that the nail will be suspended just above the bottom of the jar when the pencil is laid across the mouth of the jar.
• The water will dry up after several days and your string will be covered with salt crystals.

EXPLORE AWESOME SCIENCE EXPERIMENT VIDEOS!

How it Works:

The salt dissolves in the heated water. As the water cools, it becomes less able to hold the salt. The salt then clings to the string and forms crystals. 

Make This A Science Project:

Experiment with different types of solutions and observe and record any differences in the rate of crystals creation. Some ideas may be Epsom salts, Borax, or sugar (do not eat). 

EXPLORE TONS OF FUN AND EASY SCIENCE EXPERIMENTS!

SUBSCRIBE AND NEVER MISS A NEW SCIENCE FUN VIDEO!

previous experiment

Next experiment.

• Science, Tech, Math ›
• Chemistry ›
• Projects & Experiments ›

How to Grow Table Salt or Sodium Chloride Crystals

Easy Salt Crystal Recipe

• Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
• B.A., Physics and Mathematics, Hastings College

Table salt, also known as sodium chloride , is a crystal (a symmetrical solid substance made entirely of the same material). You can see the shape of a salt crystal under a microscope, and you can grow much larger salt crystals for fun or for a science fair. Growing salt crystals is fun and easy; the ingredients are right in your kitchen, the crystals are non-toxic, and no special equipment is required. 

Key Takeaways: Grow Salt Crystals

• Salt is the common name for the chemical sodium chloride (NaCl).
• Salt crystals are cubic, clear crystals that you can grow from any type of edible salt. Table salt, iodized salt, Kosher salt, and sea salt all work fine as a starting material.
• The key to successful salt crystal growing is controlling temperature and humidity. This is because even slight changes in these two factors dramatically influence the solubility of sodium chloride.

How to Grow Salt Crystals

It takes very little work to start the process of growing salt crystals, though you will need to wait a few hours or days to see the results, depending on the method you use. No matter which method you try, you'll need to use a hot stove and boiling water, so adult supervision is advised. 

Salt Crystal Materials

• table salt (sodium chloride)
• clean clear container
• a piece of cardboard (optional)
• string and pencil or butter knife (optional)

Stir salt into boiling hot water until no more salt will dissolve (crystals start to appear at the bottom of the container). Be sure the water is as close to boiling as possible. Hot tap water is not sufficient for making the solution .

Quick Crystals:  If you want crystals quickly, you can soak a piece of cardboard in this supersaturated salt solution. Once it is soggy, place it on a plate or pan and set it in a warm and sunny location to dry out. Numerous small salt crystals will form.

Perfect Crystals:  If you are trying to form a larger, perfect cubic crystal, you will want to make a seed crystal . To grow a big crystal from a seed crystal, carefully pour the supersaturated salt solution into a clean container (so no undissolved salt gets in), allow the solution to cool, then hang the seed crystal in the solution from a pencil or knife placed across the top of the container. You could cover the container with a coffee filter or paper towel, if you like. This cover keeps dust and debris out of the project, but permit water evaporation.

Set the container in a location where it can remain undisturbed. You are more likely to get a perfect crystal instead of a mass of crystals if you allow the crystal to grow slowly (cooler temperature, shaded location) in a place free of vibrations. Don't store the project near a window because temperature fluctuations will alternately grow and dissolve crystals.

Tips for Success

• Experiment with different types of table salt . Try iodized salt, un-iodized salt, sea salt , or even salt substitutes. Try using different types of water, such as tap water compared with distilled water . See if there is any difference in the appearance of the crystals.
• If you are trying for the 'perfect crystal' use un-iodized salt and distilled water. Impurities in either the salt or water can aid dislocation, where new crystals don't stack perfectly on top of previous crystals.
• The solubility of table salt (or any kind of salt) increases greatly with temperature. You'll get the quickest results if you start with a saturated saline solution, which means you want to dissolve salt in the hottest water available. One trick to increase the amount of salt you can dissolve is to microwave the salt solution. Stir in more salt until it stops dissolving and starts to accumulate at the bottom of the container. Use the clear liquid to grow your crystals. You can filter out the solids using a coffee filter or paper towel.
• If salt crystals won't grow, try refrigerating the salt water. Another "trick" is adding a few grains of salt to the liquid too get the action started. But, if these grains immediately dissolve, the solution just is not saturated. You need to add more salt until no more dissolves.
• 5 Ways to Make Glue
• How to Make Bubbles That Don't Pop
• Vitamin C Determination by Iodine Titration
• How to Melt Aluminum Cans at Home
• Where to Buy Saltpeter or Potassium Nitrate
• Equation for the Reaction Between Baking Soda and Vinegar
• High School Science Fair Projects
• How to Grow a Borax Crystal Snowflake
• Copper Sulfate Crystals Recipe
• Crystal Projects Photo Gallery
• How to Make Hydrogen Gas Using Simple Materials
• Grow Alum Crystals That Resemble Simulated Diamonds
• How to Grow Crystals From Salt and Vinegar
• Crystal Science Fair Projects
• How to Make Crystals
• How to Grow a Cup of Quick Crystal Needles

How to Grow Salt Crystals at Home (With Salt & Water)

• April 22, 2021
• 7-9 Year Olds , Chemistry , Christmas Crafts , Crystals

Growing Salt Crystals at Home with just salt (Sodium Chloride) and water is a super fun activity for kids.

We have previously tried some crystal ornaments for Christmas ( hearts , snowflakes , candy canes & Snow Man ) using Borax.

Unlike Borax, Salt crystal takes few days or up to a week to grow/form. But growing salt crystals is a great way to teach the science behind the salt making.

Growing Salt Crystals at Home

Things We Need

Table Salt (Sodium Chrolide – NaCl)

Color Papers cut into different shapes (optional)

Food Colors (optional)

Process of Making Salt Crystals

Fill your container halfway with warm water. Warm water helps to dissolve the salt quickly.

Add a cup of salt to the warm water and stir it continuously until the salt is completely dissolved. Repeat the process until you cannot get any more salt to dissolve. The final salt solution should not have any residue of salt. This is called a supersaturated salt solution.

Now gently pour the saltwater onto different plates. You may choose to add few drops of food color in your solution to make colored salt crystals.

Place the cut papers. Since we targeted to create crystals to make Christmas ornaments – we made a Christmas tree, star, and snowman. But this is completely an optional step. You can even form crystals just on the plate without any papers.

Now we need to place the plates in sunlight. The entire process of salt crystal formation will take about 3 to 4 days, depending upon the room temperature and availability of sunlight.

Here is our observation for the next consecutive days.

The paper is still wet buried in the saturated salt solution. We started seeing a layer of salt crystal that formed on the top of the solution.

The salt crystal layer was thickened, and we could see salt crystals evidently on top of the paper and floating later on top of the saturated solution.

Almost all the water from the saturated solution evaporated, leaving behind the crystallized salt. The layer was thick enough to show the crystals formed on top of the immersed paper.

The paper pieces were still wet. So we had to take them out from the plate to dry off completely in sunlight.

You can see Salt crystals formed all over the paper, including the backside. Now the Christmas tree-cutting had a full snowy effect due to salt crystal formation

Science Behind Growing Salt Crystals

Here are some important terms that you need to know before understanding the science behind salt crystals.

Solution:  When you mix two or three substances evenly or completely to create a homogenous mixture, that is called a solution.

Solvent:  Substance that dissolves the other one (In our experiment – Water is the solvent).

Solute:   Substance that gets dissolved (In our experiment – table salt)

To make a solution, one must dissolve a solute in the solvent. When you put the solute in the solvent, the molecules of those substances run into each other to create the dissolving process. Since these molecules are in constant motion – the solvent molecules bombard with solute molecules.

The dissolving process usually takes more time. To reduce the time taken to form the solution – you have two options:

Increase the temperature of the solution.

Try to increase motion between the molecules by stirring the solute and solvent together.

Once the solute is dissolved in solvent – that produces three types of solution:

Unsaturated Solution:  The solution which can absorb more solute.

Saturated Solution:  Where you can no longer get the solute dissolved anymore.

Super Saturated Solution:  It represents a solution that can absorb more solute than in a normal scenario. For example – Warm water can absorb more salt than water at room temperature.

So, let us understand how the Crystallization Process happened to form Salt Crystals:

Once the solute (salt) is dissolved in the solvent (water) – the ionic bonds disassociate themselves to form ions as these ions will then be attracted by the molecules in the solvent (water).

When the solution is let to cool down, the molecules in solvent (water) start bonding together, leaving the ions from salt out of place. These left-out ions create sediment in the paper as well as on the plate. As the water evaporates, the niacin and chlorine atoms bond together as there is no water molecules to separate them. As time passes, more of these fallen molecules of salt bond together to form salt crystals (in cube shapes).

Extension Ideas

We have made this a Christmas-themed science project . You can choose your favorite theme. E.g., Try making egg-shaped crystals for easter.

For example, try using different salts – repeat the experiment with sea salt, un-iodized salt, Epsom salt, borax salt, and iodized salt. Check the different shapes of crystals formed.

Change the solvent – instead of tap water, try it with distilled water and observe changes in crystal shapes.

Leave a Reply Cancel Reply

Your email address will not be published. Required fields are marked *

Name  *

Email  *

Add Comment  *

Save my name, email, and website in this browser for the next time I comment.

Post Comment

• Skip to primary navigation
• Skip to main content
• Skip to primary sidebar

• FREE Experiments
• Kitchen Science
• Climate Change
• Egg Experiments
• Fairy Tale Science
• Edible Science
• Human Health
• Inspirational Women
• Forces and Motion
• Science Fair Projects
• STEM Challenges
• Science Sparks Books
• Contact Science Sparks
• Science Resources for Home and School

How to make salt crystals

July 11, 2022 By Emma Vanstone Leave a Comment

An easy way to make salt crystals is to dissolve table salt in water and leave the solution somewhere warm until the water evaporates, leaving behind sparkly salt crystals.

We also made coloured salt by adding a little food colouring.

This activity and more salt science experiments can be found in a salt science activity sheet made as part of a collaboration with the Primary Science Teaching Trust.

You’ll need

500ml warm water

Bowl or jug

Plate or shallow bowl

Food colouring – optional

Put about 500ml of warm water into the jug.

Stir in a large spoonful of salt and stir until it is all dissolved ( when you can’t see or feel the grains any more ).

Keep stirring in salt a spoon at a time until you reach the point where no more salt will dissolve ( we call this a saturated solution ).

Pour a small amount of the salty mixture onto a flat bowl or plate and leave it somewhere warm. Outside in the sun is ideal.

After a few days, you should see crystals appear.

How to make coloured salt crystals

Make as above but add a little food colouring to the saturated salt solution.

Why do salt crystals form?

When you stir salt into warm water, it dissolves. It looks like the salt has disappeared, but it has actually mixed with the water to form a transparent solution.

When the salty solution is left in a warm place ( we left ours on a windowsill ), the water evaporates, leaving behind salt crystals.

Evaporation of water happens when water gets enough energy to change state from liquid water to water vapour ( a gas ).

Extension Tasks

Water evaporates faster when there is a bigger surface area. This is because more water is exposed to the air. Try leaving the same volume of water in a tall container and in a shallow bowl. The water in the shallow bowl should evaporate faster than the water in the tall container.

More Science for Kids

Use salt to cool a drink quickly!

Make ice cream also using the supercooling power of salt.

I’ve also got lots of easy kitchen science ideas for you to try!

Last Updated on May 5, 2023 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

Leave a reply cancel reply.

Your email address will not be published. Required fields are marked *

Salt Crystals

(water, salt, string, pencil, container)

• Boil about 1 cup (250 ml) water.
• Add 1/4 cup salt.
• The solution will be supersaturated when salt crystals begin to collect on the bottom of the pan.

Two options for growing salt crystals:

• Soak a piece of cardboard in the solution until it is saturated and sinks to the bottom of the pan. The cardboard will act as a template or base for crystal growth. Put the pan in a sunny location. Crystals will form as the water evaporates.
• Simply place the pan of solution in a warm location, and allow crystals to grow without a template. Both methods work. The salt crystal will grow over several days.

Try several pans, and study how the growth of crystals varies between them.

Notes to Parents:

• Every parent must use their own judgment in choosing which activities are safe for their own children.  While Science Kids at Home makes every effort to provide activity ideas that are safe and fun for children it is your responsibility to choose the activities that are safe in your own home.
• Science Kids at Home has checked the external web links on this page that we created.  We believe these links provide interesting information that is appropriate for kids.  However, the internet is a constantly changing place and these links may not work or the external web site may have changed.  We also have no control over the "Ads by Google" links, but these should be related to kids science and crafts.  You are responsible for supervising your own children.  If you ever find a link that you feel is inappropriate, please let us know.

Kids Science Gifts   Science Experiments   Science Fair Projects   Science Topics   Creative Kids Blog

Kids Crafts   Privacy Policy   Copyright © 2016 Science Kids at Home, all rights reserved.

Science Project Ideas

How to Make Salt Crystals

Creating crystals of table- or Epsom salt or sugar can be an excellent idea for your next science fair project. The process is simple and needs minimum adult supervision.

Salt (sodium chloride) consists of tiny cubic crystalline structures where the molecules are arranged in an orderly, geometric and repeating pattern, and you can grow your own salt crystals pretty easily.

Salt Crystal Experiment

Here are the instructions on making salt crystals. The method is similar for Epsom and sugar as well.

Materials Required

• ½ cup water
• 3 cups salt

Growing Homemade Salt Crystals

• Heat about 120 mL of water in a pan. Heating should continue until the water begins to bubble.
• Stop heating the pan.
• Take about 60 -120 mL by volume of salt and stir the water until it is clear. If you do not find any undissolved particle even after stirring, then add more salt and stir. Keep doing this until you find the grains do not dissolve anymore and pop out of the solution. Under this condition, the solution is said to be supersaturated as it contains more salt than the water can accommodate.
• Pour the contents of the pan in a jar being careful not to pour out any undissolved residue.
• Add a few drops of food color to the solution.
• Take a pencil long enough to lie across the mouth of the jar and tie a string at its center. You can also use a popsicle stick or any small stick for serving the purpose.
• Cut the part of the string hanging from the pencil to an appropriate size. The free end of the string should not touch the bottom of the jar lest the crystals formed are small and lumpy.
• Place the pencil on the jar with the string immersed in the solution. If the pencil wobbles, tape it to the jar. The string should not lean against the walls of the container since this can inhibit the augmentation of the structures.

• Keep the arrangement in a safe place free of any disturbance.
• If you want to grow crystals fast, place the jar in the sun or near a fan. The lump so created will, however, consist of small crystals as they stop increasing size after a certain period. If you want a large single crystal instead, keep it in a cool, shady place devoid of movement and vibration.

• Those of you experimenting with Epsom can refrigerate the jar for a quicker growth of the needle crystals. Alum crystals become visible very quickly, sometimes taking shape within a few hours. But the full process might take a couple of days. Table salt crystals start forming in a couple of days; maybe a week and take around two weeks to finish off.

• Check back every day to track the crystallization. The rate of growth increases with cooling of the water and evaporation.

You can try to make crystals with different substances and compare their rate of growth, color, taste, size, duration of formation, etc. Also test crystallization using tap water and distilled water. In this case, your hypothesis could be crystals of salt grow faster in tap water. After the experiment, note down your observations and tally them with your hypothesis.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

Get Your ALL ACCESS Shop Pass here →

Salt Crystals Experiment

This  salt crystals science project is a fun and easy  science experiment for kids , perfect for home or school. 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!

Here we went with an Easter egg theme for our salt crystals. But you could use paper cutouts of any shape or even string or pipe cleaners suspended in the solution.

• Construction Paper
• Container and Spoon {for mixing salt solution}
• Tray or Plate
• Hole Puncher and String {optional if you want to hang them when you are finished}

Instructions:

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!

Also check out how we have done this with paper leaves , snowflakes , gingerbread men and hearts for different themes!

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!!

How To Grow The Best Salt Crystals

To make the best crystals, the solution has to cool slowly. This allows the forming crystals to reject any impurities that are also caught up in the solution. 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!

How Do Salt Crystals Form

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, water molecules no longer separate the atoms (niacin and chlorine). They begin to bond together, forming the special cube-shaped crystal for salt.

Click here to get your FREE Science Challenge Calendar

Set Up A Salt Crystals Science Project

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?

Check out these helpful resources…

• Science Fair Board Layouts
• Tips For Science Fair Projects
• More Easy Science Fair Project Ideas

More Fun Science Experiments With Salt

• Investigate what makes ice melt faster
• Use salt and ice to make ice cream in a bag
• Or homemade slushies
• Explore how salt changes the density of water
• Try this fun salt and soda experiment
• Set up a salt volcano

Printable Science Projects Pack

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

• 90+ classic science activities  with journal pages, supply lists, set up and process, and science information.  NEW! Activity-specific observation pages!
• Best science practices posters  and our original science method process folders for extra alternatives!
• Be a Collector activities pack  introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
• Know the Words Science vocabulary pack  includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
• My science journal writing prompts  explore what it means to be a scientist!!
• Bonus STEAM Project Pack:  Art meets science with doable projects!
• Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics

• Pingback: Preschool Science Experiments and Science Activities

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.

Are you adding enough salt? You have to create a saturated solution! Email me [email protected]

Can you pour the borax solution over the egg shapes in the pan?

Comments are closed.

Subscribe to receive a free 5-Day STEM Challenge Guide

~ projects to try now ~.