Building materials for earthquake-prone areas
The materials required for this science project:
- 1 transparent plastic or glass tray ( at least 50mm in depth)
- Tap water
- 1 spherical metal ball with hook
- 1 meter long string
- 1 concrete slab
- 6 bricks
- 1 piece of timber, about the same size as the concrete slab
- 1 ruler
- 1 small table
1. For this experiment, the independent variable is the type of building material used – timber, brick or concrete. The dependent variable is the amount of vibration absorbed by the building material. This is determined by measuring the height of the waves which form inside the tray of water. The constants (control variables) are the size of the tray, the depth of the water, the weight of the ball and the length of the string.
2. The experiment is set up as shown in figure 1 above. The string is used to tie the metal ball and suspend it from the ceiling or from a coat hanger. The suspended metal ball should be able to swing freely as shown.
3. The timber is placed on the small table. The length of the string is adjusted so that when the metal ball swings towards the table, it will knock against the side of the timber as shown in figure 1.
4. The transparent tray is filled with water up to 2 cm deep. The tray is then placed on top of the timber. Once the water is calm and settled, swing the metal ball and allow it to knock against the side of the timber. Observe and record the height of the wave in the water during impact. Repeat the test 4 times and record the results in the table given below.
5. Procedures 3 and 4 are repeated using the bricks and the concrete slab. All the measured results are recorded in the table given below.
Use safety gloves and common sense when handling heavy/hard objects.