Crystal Formation Task

Year 9 Science

What is a Crystal?

A crystal is a solid material that consists of atoms, molecules and ions that are arranged in an orederd pattern, extending in three spacial dimensions.

Some examples of crystals in nature are snowflakes, diamonds and common salts.
You could make crystals at home buy using; Epson salt and hot water or alum ( found in supermarkets in the spice section) and hot water. For more information go to


Day One- 1. Place 25 grams of potash alum in a beaker
2. Add 170 ml of hot water
3. Stir mixture until crystals have dissolved
4. Filter the warm solution through a filter funnel (with filter
paper inserted) into another clean beaker.
5. Cover the beaker with solution in it with a watch glass and set
aside in a cool sheltered place.
6. Allow it to stand overnight.

Day Two- 1. Observe the beaker of the solution. The bottom should have become a covered layer of small crystals.
2. Carefully pour off the solution above the crystals into a clean
beaker and set it aside.
3. If no crystals have formed you can add a crystal from the
original alum.
4. Let it stand overnight again.

Day Three- 1. Observe the changes of the crystals in the beaker.
2. If nothing has happened, crystal growth can be induced
by scratching the bottom of the beaker with a stirring rod.
3. Transfer one good crystal with tweezers to the beaker
containing the clear solution from before.
4. Take a picture of the crystal near a ruler and measure the
level of liquid.
5. Cover the solution with a loose-fitting paper that permits
the water to evaporate slowly.
6. Allow the solution to stand in a draft free area with no
direct sunlight. The aim is to keep the temperature as
constant as possible.

Once a Week- 1. After day three, once a week record the level of
the solution in the beaker without disturbing
the crystal.
2. Take a photo of your crystal with a ruler.
3. Estimate how much your crystal has grown.
4. If small crystals appear, carefully remove them or
remove the main crystal.
5. Dry it with a tissue
6. Carefully remove crystal buds.
7. Do not touch the crystal with your fingers.

After Ten Weeks- 1. Remove the crystal carefully from the beaker.
2. Dry it with a tissue.
3. Use a ruler to measure its length, width and height.
4. Compare the measurements with the size of your
original crystal.
5. Take photos.

Your crystals vary in different shapes and sizes depending on what chemicals you use to make them.
Different crystals include: -Amethyst
-Cactus Crystal
- Clusters
When light passes through crystals from more dense to less dense light is refracted.
Some optimum conditions for crystal growth:
-Do not keep in the dark
-Don't crystalize to concentrated.
-Don't hurry.


Clear water like substance.
5.5cm water.


Little specks of crystals forming on the bottom of the jar.
On top still a water like substance is present.
3.9cm water.


Some more little specks of crystals and some of the lager crystals keep growing.
Clear water like solution on top.
3cm water


Larger crystals are growing but the smaller crystals are shrinking.
Clear water like solution on top.
3.2 cm water.


My crests grew well at the beginning but during the holidays they started to shrink.
My crystals were about 1cm wide and 0.4cm thick.
When you look through the crystal in sunlight you can see that light is refracted.You can see through the crystal, but the image on the other side seems zoomed in.

Overall this experiment wasnt very successful. My crystals didnt grow very big and towards the end the water level seemed to be rising. If i was to do this experiment again i would keep my crystals in a cupboard rather than in a dark corner. Apart from that i really enjoyed this experiment.

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