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This summer, we wanted to grow overnight crystals with alum powder!

Amelia got a little kit for her birthday we finally had a chance to use. This kit was so cool because it had figurines we dipped into the solution and overnight it grew crystals. Part of the kit also had things to make necklaces with!

The key to these crystals working is simply alum powder.

Grow Overnight Crystals With Alum Powder

There are several ways to make crystals, but using alum powder and hot water is the easiest! Most of the kits you buy online will be this method. Here is a link to our favorite crystal making kit and some more science ideas.

What is Alum Powder?

Alum powder, which is typically potassium alum (potassium aluminum sulfate) has a chemical compound of KAl(SO₄).12H₂O. It has been used for thousands of years, and it has many known uses. Purifying drinking water, taxidermy, deodorants, pickling food, and even in fire extinguishers.

Due to its chemical structure, it makes the best compound for crystal growing.

Here is the process on how alum powder works to grow crystals:

First, you heat up some water in a container. Next, you will slowly add alum powder to the hot water while stirring constantly. Keep adding alum powder until no more will dissolve and the solution becomes saturated. Saturated means there is so much alum powder in the water that it cannot dissolve any more.

Crystallization:

Let the saturated solution cool down slowly. As the solution cools, the excess alum powder will come out of the solution and start to form crystals around any tiny particles that are present in the water, like dust or small crystal fragments. These tiny particles act as seeds for the crystal growth.

How You Can Grow Bigger Crystals:

You can influence the size and quality of the crystals by using a seed crystal. To do this,after the solution cools down a bit and you see some small crystals forming at the bottom, filter out the solution. Tie a thread to a well-shaped seed crystal and suspend it in a clean container filled with the filtered alum solution. This allows the crystal to grow larger and more uniformly. Many of the science kits for kids already come with seed crystals making this very easy!

Over time, the crystals will continue to grow as more and more alum comes out of the solution and attaches to the seed crystal. You can end up with large, well-defined crystals..

Why Getting A Kit Is a Better Idea:

You can definitely grow your own crystals with hot water and alum powder, but getting a kit is a great idea for kids because it comes with other things like figurines, jewelry, and seed crystals to make this project easier and more exciting. They have so many neat kits you can choose from, it will have all the instructions and ingredients you need too.

If you are looking for a science project for kids, growing alum crystals is a fun and easy way to learn about crystals and the process of crystallization.