Making Crystals

My Science Project


1.  What is a crystal?

Crystals are molecules that turn into patterns and therefore creating something solid

2.  What substances can be used to make crystals?

Minerals can be used to create crystals but the environment surrounding the minerals also play a big part.

3.  What are some examples of crystals in nature? What household items can you also grow crystals from?

There are quartz and diamond and there are different variations of both them. You can grow crystals from salt and sugar.

4.  Explain the process of crystal growth.

Crystals grow by being heated up then cooling down. While being heated up the minerals that will make up the crystals mix with a liquid but then when it cooling down the molecules attract each other and form a crystal.

5.  Explain how crystals can grow in different shapes and sizes.

A crystals form is dictated by a range of things the temperature, where its growing, what minerals it made from and how much of each substance it has.

6.  Outline a few different types of crystals.

Crystals can be classified by shape as cubic, hexagonal, trigonal, tetragonal, orthorhombic, monoclinic and triclinic or chemical structure covalent, metallic, ionic and molecular crystals.

7.  What effect do crystals have on light travelling through them? (relate to reflection, refraction, dispersion and diffraction)

8.  What are the optimum conditions for crystal growth?

A warm stable tempreture is the best conditions for growing  a crystal

The Plan for Making Crystals

-  Tuesday – method + materials

Make sure all apparatus is clean and dry.

Place approximately 25 g of potash alum in a beaker (250 ml or bigger) and add approximately 170 ml of hot water. Stir the mixture until all the crystals have dissolved.

(NOTE: don’t use all the alum you have been given – keep a few crystals back in reserve in case you need to “seed” the solution later.)

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 filter paper used for filtration discarded.

-  Wednesday – method + materials

The next day, observe the beaker of solution. The bottom should have become covered with a layer of smallish crystals which formed spontaneously as the solution cooled. Carefully pour off the clear solution above the crystals into a clean beaker and set it aside for later, leaving the crystals behind in the other beaker. If for any reason, no crystals have formed after leaving the solution to stand overnight, the solution can be “seeded” by adding a crystal from the original alum. Let it stand overnight again and observe the formation of crystals. Alternatively, if nothing has happened, crystal growth may also be induced by scratching the bottom of the glass beaker with a glass stirring rod.

From the bed of crystals, one good symmetrical crystal or group of crystals needs to be selected to act as “seed” for your big crystal. Using a plastic spoon, spatula, tongs or tweezers, transfer the selected crystal to the beaker containing the decanted solution, trying to place it centrally in the beaker.

(A good technique to promote uniform growth is to suspend the crystal with a nylon thread tied round a stirring rod or pencil resting on the rim of the beaker. This step is not essential, however, and good a crystal can usually be obtained just by leaving the crystal on the bottom of the beaker.)

-  Thursday – method + materials

Take a picture of the crystal, preferably close to a ruler so that you can measure its size, and mark the level of the liquid in the beaker. Record the date in your diary.

Cover the solution with a loose-fitting paper hat that permits water to evaporate slowly whilst keeping out dust.

Allow the solution to stand in a draft free location, not in direct sunlight or near a heater. The aim is to keep the temperature as constant as possible.

On the hoildays

Once a week record in your diary the level of the solution in the beaker and if possible, without disturbing your crystal, take a picture of it close to a ruler so that you can estimate how much it has grown. Try and avoid disturbing crystals during the growth phase as this may induce additional crystals to grow.

If small isolated crystals appear, you may be able to carefully remove them with tweezers. Be careful not to disturb your big crystal. If small crystals grow on the main crystal, remove it, dry it with tissues, and carefully remove the adhering buds. Do not touch the crystal with your fingers. The crystal is likely to be quite fragile, fairly brittle, and easily damaged, so should not be dropped or bumped.

When it is decided to terminate the experiment (after about 10 weeks or so), remove your crystal very carefully from the beaker, dry it with tissues and with a ruler measure its length, width and height. Compare the measurement, if you can, with the size of the original crystal. Take a photo of the completed crystal (next to a ruler to confirm the size)

To complete the artistic component, students will digitally photograph the completed crystal, and using the effects of light and shade, colour and other techniques, produce an artwork featuring the crystal and demonstrating the principles of diffraction/ reflection/ dispersion using light and or objects/images (see examples). The ingenuity of students will be encouraged to produce an innovative picture which highlights the crystal.

The Project

Each student, if working individually, or team, must also submit a one page A4 report, detailing the growth and artistic processes, which should include:

· A brief account of how their crystal grew

· Including recordings of liquid levels in the beaker

· The estimated size of the crystal, as measured by photographing the crystal in its beaker adjacent to a ruler, say once a week over the duration of the experiment.

· A record of the final dimensions of the crystal at the end of the experiment. (For this, the crystal should be removed from the beaker, dried, carefully laid on a flat surface, and photographed with a ruler next to it.)

· 25 word or less statement detailing how the artwork demonstrates the properties of the crystal

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