Effect of area of contact on frictional force in Friction – Class 8 Science Experiment
Chapter Name: Friction
Activity Name: Effect of area of contact on frictional force in Friction
Activity Description:
In this experiment, we investigate the effect of the area of contact on the frictional force between two surfaces.
We use a spring balance to measure the applied force required to move a brick horizontally, and then we compare the frictional forces in two different scenarios: with one brick and with two bricks stacked together.
Required Items:
- Brick(s)
- String
- Spring balance
- Flat surface
Step by Step Procedure:
- Tie a string securely around the brick.
- Place the brick on a flat surface.
- Attach the spring balance to the string.
- Pull the brick horizontally using the spring balance until the brick just begins to move. Note down the reading on the spring balance.
- Record the applied force reading on the spring balance.
Experiment Observations:
- With one brick: Note down the reading on the spring balance when the brick just begins to move.
- With two bricks stacked: Place another brick over the brick tied to the spring balance or press it vertically with your hand, then measure the force of friction as described above.
Precautions:
- Ensure the string is tightly secured around the brick to avoid slipping.
- Use a flat surface to conduct the experiment for accurate measurements.
- Take multiple readings to ensure the consistency of results.
Lesson Learnt from Experiment:
The experiment demonstrates that the frictional force between two surfaces is affected by the normal force (the force pressing the surfaces together). When we increase the normal force by adding an extra brick or pressing vertically, the frictional force also increases. This observation leads to the conclusion that friction is proportional to the normal force, represented as Friction ∝ Normal Force.
