Which type of wood makes the best charcoal for drawing? Experiment with using different types of wood; softwoods such as willow, hardwoods such as oak and other plant materials such as grape vine. The simple process of making your own charcoal for crafting and drawing can be used for maths challenges for older children.
INVESTIGATE: Spot and identify twigs from different trees to cut and collect into a tin for burning on the fire. The tin needs a firm fitting lid and a hole made in the top for smoke and gases to escape.
For an added maths challenge, record the length and weight of your twigs to compare with the resulting charcoal later.
OBSERVE and DISCUSS: Place the tin of wooden sticks on the fire, cover with burning embers but with the hole in the tin exposed. You will see smoke coming out of the hole. Keep the fire hot until the smoke and gases stop being released through the hole in the tin. This will take about an hour depending on the size of your fire and tin. Carefully remove the tin and leave to cool.
CREATE: Use your charcoal to draw and decorate paper, wooden discs or stones. Compare the different materials. Which do you prefer for drawing?
Measure your twigs before and after charing to record the changes in length. Alternatively, cut all the twigs from the same tree to the same length, e.g. oak 9cm, willow 12cm. Keep one of each of the twigs out of the tin to compare the length with the charcoal sticks later.
Does the volume and density of wood change after it has been transformed into charcoal?
Do different twigs change at different rates?
How many centimetres of drawing do you estimate 1cm of charcoal will produce?
Which type of wood produces the longest charcoal line?