Observing the variation of friction in Friction – Class 8 Science Experiment

Chapter Name: Friction

Activity Name: Observing the variation of friction in Friction

Activity Description:

In this experiment, we observe the variation of frictional force when a heavy box is pushed horizontally on a floor with a small force. The objective is to understand static friction and its limits.

The box initially does not move due to the presence of static friction, which opposes the applied force. As the applied force is gradually increased, the static friction force also increases, maintaining equilibrium until a certain limit is reached.

Required Items:

1. A heavy box
2. A flat and smooth floor

Step by Step Procedure:

1. Place the heavy box on a flat and smooth floor.
2. Apply a small force horizontally to the box to attempt to move it.
3. Observe that the box does not move initially due to static friction.
4. Gradually increase the applied force while noting any changes in the box’s movement.
5. Continue increasing the force until the box starts moving.

Experiment Observations:

1. The box does not move initially when a small force is applied.
2. As the applied force increases, the box remains stationary due to the increasing static friction.
3. At a certain point, when the applied force exceeds the limit of static friction, the box starts moving.

Precautions:

1. Ensure that the floor is flat and smooth to avoid any inconsistencies in the observations.
2. Use a heavy box to ensure substantial static friction.

Lesson Learnt from Experiment:

Through this experiment, we conclude that static friction is a self-adjusting force, increasing in response to the applied force until it reaches its limit. Once the applied force exceeds the limit of static friction, the body starts moving, and kinetic friction comes into play.

Understanding the behavior of frictional forces is crucial in various real-life scenarios, such as determining the force required to move objects or preventing unwanted movements.