Crystals are formed when atoms line up in patterns and solidify. There are crystals everywhere — in the form of salt, sugar, sand, diamonds, quartz, and many more!
To make crystals, you need to make a very special kind of solution called a supersaturated solid solution. Here’s what that means: if you add salt by the spoonful to a cup of water, you’ll reach a point where the salt doesn’t disappear (dissolve) anymore and forms a lump at the bottom of the glass.
The point at which it begins to form a lump is just past the point of saturation. If you heat up the saltwater, the lump disappears. You can now add more and more salt, until it can’t take any more (you’ll see another lump starting to form at the bottom). This is now a supersaturated solid solution. Mix in a bit of water to make the lump disappear. Your solution is ready for making crystals. But how?
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Here’s what you need:
- pencil or wooden skewer
- string
- glass jar (cleaned out pickle, jam or may jars work great)
- 8 cups of sugar
- 3 cups water
- paper clip
- adult help and a stove
- food coloring is optional but fun!
If you add something for the crystals to cling to, like a rock or a stick, crystals can grow. If you “seed” the object (coat it with the stuff you formed the solution with, such as salt or sugar), they will start forming faster. If you have too much salt (or other solid) mixed in, your solution will crystallize all at the same time and you’ll get a huge rock that you can’t pull out of the jar. If you have too little salt, then you’ll wait forever for crystals to grow. Finding the right amount takes time and patience.
Download Student Worksheet & Exercises
1. If you plan on eating the sugar crystal when you’re done you probably want to boil water with the jar and the paper clip in it to get rid of any nasties. Be careful, and don’t touch them while they are hot.
2. Tie one end of the string to the pencil and the opposite end to the paper clip. (You can alternatively use a skewer instead of a piece of string to make it look more like the picture above, but you’ll need to figure out a way to suspend the skewer in the jar without touching the sides or bottom of the jar.)
3. Wet the string a bit and roll it in some sugar. This will help give the sugar crystals a place to start.
4. Place the pencil across the top of the jar. Make sure the clip is at the bottom of the jar and that the string hangs straight down into the jar. Try not to let the sting touch the side of the jar.
5. Heat 3 cups of water to a boil
6. Dissolve 8 cups of sugar in the boiling water (again be careful!). Stir as you add. You should be able to get all the sugar to dissolve. You can add more sugar until you start to see undissolved bits at the bottom of the pan. If this happens, just add a bit of water until they disappear.
7. Feel free to add some food coloring to the water.
8. Pour the sugar water into the jar. Put the whole thing aside in a quiet place for 2 days to a week. You may want to cover the jar with a paper towel to keep dust from getting in.
You should see crystals start to grow in about 2 days. They should get bigger and bigger over the few days. Once you’re happy with how big your crystals get, you can eat them! It’s nothing but sugar! (Be sure to brush your teeth!) This one (left) us about 6 months old.
There you go! Next time you hold a pencil, throw a ball, or put on a shoe try to keep in mind that what you’re doing is using an object that is made of tiny strange atoms all held tightly together by their bonds.
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Yes, in the Live Class / Recordings section – you’ll find them listed each week near the end of each student handout worksheet. You’ll also find them in the monthly review sessions we do for each topic in the live classes.
Hi Aurora! We are enjoying all the science experiments and videos. My son and I are both learning a lot, lol! I was wondering if there are vocabulary words available for the lessons. It just occurred to me to ask, in case I’ve missed them. If not, I can certainly make vocabulary lists to use. I wanted to check with you before I did that though. Thank you for this amazing science curriculum, and the math too! Our family and friends cannot believe how much Ian is learning!
A grocery store should have the supplies for this experiment.
Which are the best stores to find ingrideants?
The paperclip is used to hang a string in the sugar mixture (if you don’t use a pencil or wooden skewer).
In the list of things needed, it mentions a paper clip. What is it for?
I didn’t know I can make my own rock candy! Great!
Please take a look at step 8. It shares details on how long the crystals take to grow.
Any grocery store should have these supplies. Generic brands should be fine.
How long dose it take?
Where would be the best place to buy ingredients? And which brand is best?
The water needs to be saturated with sugar. Otherwise, the crystals will be small…if they grow at all. So it is best to use the full 8 cups of sugar.
Is it okay if we put in 4 cups of sugar? Or no?
Crystals may start to grow anywhere along the portion of the stick that is submerged in the sugar-water solution.
were does it start? i mean does it start to grow at the top or down?bye
They will look like little crystals. The picture at 9 minutes 16 seconds into the video shares what they will look like after months of growth.
how will it look like when it will grow?
If you “seed” the stick, you should start to see growth within two day.
…We had to put 4 cups of sugar in it…and 1 and a half cup of water in.How much weeks will it take it do grow?bye .
Yes because they are sugar, it’s fine to eat these as long as you haven’t mixed anything else in with it. You can use food dye to color the crystals.
to we eat the crastals ?or can we chance the colour?thank you!bye…
1) Yes, waxing part of the wooden rod may help prevent mold, but you should only put wax on the part of the stick that is outside of the sugar water mixture.
2) Yes, crystals will most likely grow on any sugar “seeds” that fall from the wood rod.
3) As long as you saturated the water with sugar, crystals should grow. But, remember that crystals can only grow on the portion of the rod that is submerged in the sugar water. So using a larger container means you’ll have to make a larger amount of sugar water.
4) The mosquito was probable attracted to both the water and the sugar. Sugar is one of the ingredients in mosquito traps.
Hi. My daughter and I started this experiment on 8/25/21 and split the solution into 4 jars (2 larger and 2 smaller jars). On 9/14 we noticed 3 skewers were growing mold. That day, we replaced 2 skewers that were not growing crystals with freshly seeded skewers to see if crystals would form. 10/4 We noticed that all skewers were growing mold above the solution line and one jar had a mosquito in it (yuck!). Out of the 4 jars, two skewers grew crystals while all the others grew crystals on the bottom of the jar. The smaller jar had the most well defined crystals growing.
My daughter’s (Zuri age 9) questions about this experiment :
1) Do you think that waxing the tip of the wooden rod would help prevent mold from growing?
2) Are crystals growing on the bottom of the jar due to the seeded sugar falling off of the wooden skewers?
3) Does the size of the jar effect how well the crystals form?
4) Do you think the mosquito was attracted to the sugar, the water, or both?
Can I cut down the reicipe
It depends on how long you leve your stick in! The longer you leave it, the larger your crystals will grow.
How much dose it make?Zoya,age 93/4
Hi! it has been two days and there is nothing on the stick what is wrong.
It depends on what you use in your solution and the temperature it remains at. Borax (sodium tetraborate) takes only a few hours, but salt will take a month unless you add heat, then it’s only hours. Sugar is days to weeks, unless you heat it, then it’s faster. Also, if you don’t have a super-saturated solution, you’ll be waiting forever and no crystals will form. The solution has to be just right for crystals to start to form.
how long does it take for it to be come a crystal
in your rook candy video why did you not sow what it lookd like???
You can put as many as you want to, but the more sticks you put in there the more likely they are to run into each other and make one giant rock candy! You can do three separate jars, one for each child, and even use food dye to color them!
Can you only put one stick in the jar?
Can you put 3?
I have three children.