Make Your Own Chalksticks

Aim of Experiment

At the end of this experiment you will have your own chalkstick which you can use to create pictures.

What You Need

• Six clean, dry egg shells
• Plastic bowl and stone (or pestle and mortar)
• Cup
• Kitchen towel
• Flour
• Warm water
• Pigment

Pigment can be obtained from any good art supplier. The easiest pigments to obtain are powder paints. Your art supplier may have a range of natural pigments, which would have been the only pigments available to people in the past. To see where we got our pigments from, and to find on-line suppliers, take a look at our suppliers section.

What To Do

1. Take your six clean, dry egg shells and grind them into a fine powder. You can use a plastic bowl and a stone, or a pestle and mortar if available.
2. In a cup mix a heaped teaspoon of flour with warm water to make a smooth paste.
3. Next, mix the ground egg shells with the flour paste.
4. Add a small amount of pigment and mix thoroughly.
5. Mould the mixture into a stick shape, and leave to dry on some kitchen towel for at least 24 hours.

The Science

The chalkstick requires two main components - a pigment and a binder. The pigment is the small insoluble coloured particle which gives the chalkstick its colour. The binder is the substance which holds the chalkstick together. The binder is the flour and water paste.

Why not try making another chalkstick and adding more pigment to see what happens?