Rachel's Crystal Experiment

Crystal Information

1. Most crystals are naturally occurring; solid,
inorganic, (not living) materials called minerals. Inorganic compounds not
found naturally as minerals also form crystals.

2. Crystals can be made from a variety of substances. The crystals we will be making will be large aluminium potassium sulphate dodecahydrate crystals.

3. Some examples of crystals occurring in nature are: snowflakes, types of rock, ice and more. You can grow crystals from household item such as salt, sugar, Vaseline,
ammonia and food dye.

4. Crystals are made up of tiny different atoms which bond together to form the crystal.

5. This depends on 2 factors: The internal symmetry of the crystal, and the relative growth rates along the various directions in the crystal.

6.Different types of crystals:

Borax Crystals- Naturally clear crystals.

Sugar Crystals- An edible sugar crystal.

Copper Sulphate Crystals- form blue diamonds. They are really easy to grow.

7. Crystals generally have a high refractive index meaning that light inside them is bent and travels slower than in air. As a result of their high refractive index, they often have total internal reflection.

8. The best conditions to grow crystals in are: under heat or in a humid place and
away from any vibration, as vibration can slow down the growing process. Crystals also grow best under a light source, but not in direct sunlight.


· 250ml beaker

· Filter funnel

· Filter paper

· Hot water

· Stirring rod

· Tweezers

· Tongs

· Spatula or plastic spoon

· Nylon thread

· Watch glass or paper hat

· Ruler

· Camera


Session One - Tuesday

Place 25mg of potash alum in a beaker and add 17oml of hot water. Stir the mixture until the crystals have dissolved. Filter the warm solution through a filter funnel (in which filter paper has been inserted) into another clean beaker. Cover the beaker of solution with the watch glass or fresh filter paper and set aside in a cool sheltered place and allow it to stand undisturbed overnight. The first beaker and funnel can be washed and dried and the residue and the filter paper used for filtration should be discarded.

Session Two - Wednesday

Observe the beaker of solution. The bottom should be covered with a layer of small crystals. If nothing has happened, the solution can be 'seeded' by adding a crystal from the original alum. Alternatively, crystal growth may also induced by scrathcing the bottom of the beaker with a stirring rod. If crystals have started forming, start session three.

(Unfortunately, we got no crystals whatsoever, so we started the process agai,n but we still kept our old ones just in case)

Session Three - Thursday

Carefully decant the clear solution above the crystals into a clean beaker and set it aside for later, leaving the crystals behind in the other beaker. Let it stand overnight again and observe the formation of the crystals.

(On Thursdya, we finally got crystals from our first batch and there was enough to divide among the three of us to take home)

Safety Sheet


After 3 Days: Crystals appear the same shape and size. Same amount of liquid in jar. Miniscule crystals have appeared all around the edges of the jar. There are many of them about the size od sand. Attempted to put crystal on the wire and leave it hanging from a pencil.....It lasted about a day and then fell off

After 6 Days: Main crystals are still looking the same. The small crystals around the edge have increased in size.

After 13 Days: Crystal have slightly increased in size. Have noticed the smaller crystal have grown larger, whereas the main crystal has barely grown.

After 20 Days: After seven days since last updated, the amount of liquid in my jar has reduced significantly. Also, my main crystal has slightly increased in size.

Crystal Activity Sheet - Crossword
Crystal Activity Sheet - Crossword Answers


The main crystals in my jar grew only a slight amount during the holidays, whereas the smaller ones grew significantly. The amount of liquid in the jar reduced slightly, but the majority of the liquid is still there.

My crystal experiment worked fairly well. Our first batch of crystals produced nothing, so we tried for a second time and left it overnight, only to find that our first batch had miraculously produced a few crystals for us. We then took the crystals home and watched them develop of the holidays. My crystals only slightly increased in size, but the amount of liquid decreased significantly. My main crystal turned out okay and I am happy with the shape of it, however it is only 1.2cm long. I also had this strange crystal, which was made up of hundreds of tiny crystals, which was 2.2cm long.

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