Comparing the strength of solid wood with that of plywood
The materials required for this science fair project:
- 4 oak wood planks (proposed size 100mm x 25mm x 500mm)
- 4 redwood planks (proposed size 100mm x 25mm x 500mm)
- 4 plywood planks (proposed size 100mm x 25mm x 500mm)
- You can purchase the wood from a hardware/home improvement store (eg. Lowes or Home Depot)
- 40 weights, each 0.5 kg
- 1 rope, about 2 meters in length
- 1 electric drill with appropriate size drill bits
- 1 ruler
- 1 vice
- 1 solid table
1. For this science fair project, the independent variable is the type of wood used for testing – oak wood, redwood or plywood. The dependent variable is the average strength of the wood. This is determined by applying weights and noting the breaking point of each wooden plank. The constants (control variables) are the size of the wooden planks and the position where the weight is applied.
2. The experiment is begun by inspecting the dimensions of the wooden planks and ensuring that all of them are of the same size.
3. A hole is drilled in each of the 12 planks to be tested. The position of the hole is 30mm from one end of the plank, and in the center of the plank’s width ( 50mm from each side).
4. The vice is fixed to the table. One of the oak wood planks is fixed to the vice by the end without the hole, as shown in Figure 1 below. The string is tied to the hole in the other end of the plank. The weights are added, 0.5kg at a time, to the string until the wooden plank snaps. The test is repeated with the remaining 3 oak planks. The average breaking weight of the 4 planks is calculated and recorded in the table given below.
5. Step 4 is repeated using the redwood and plywood planks. The average breaking weights are calculated and recorded in the table given below.
Ensure that safety equipment (gloves/goggles) are worn when handling power tools. Tools should be handled only by an adult