Expansion and shrinking of wood
The materials required for the science fair project experiment: :
- 1 redwood block (50mm x 20mm x 100mm)
- 1 teak wood block (50mm x 20mm x 100mm)
- 1 black oak wood block (50mm x 20mm x 100mm)
- 1 red maple block (50mm x 20mm x 100mm)
- 1 caliper
- 1 oven
- 1 pair of gloves
- 1 black marker pen
1. For this science fair project, the independent variable is the type of wood used – redwood, teak, black oak and red maple. The dependent variable is the change in dimension of the wood after being dried in the oven, and at normal room humidity. This is determined with the use of the caliper. The constants (control variables) are the size of the wooden blocks, the air humidity of the surroundings and the humidity inside the oven.
2. The science project experiment is started by cutting the 4 types of wood and ensuring that their dimensions are 50mm x 20mm x 100mm each. The 50mm side should be along the direction of the growth rings. Record the dimensions in the table below.
3. Using the marker pen, label the wooden blocks with the name of the type of wood.
4. Set the oven to a temperature of 120°C. The 4 wooden blocks are placed inside the oven for the next 24 hours. The heat from the oven will convert the moisture in the wooden blocks into vapor.
5. Use the gloves to handle the hot wooden blocks. The dry wood blocks are removed from the oven after 24 hours and their dimensions measured again using the caliper. All the measurements are recorded in the table below.
Be careful when removing the hot wooden blocks from the oven. Use gloves to protect your hands.