Effect of roughness on frictional force in Friction – Class 8 Science Experiment

Chapter Name: Friction

Activity Name: Effect of roughness on frictional force in Friction

Activity Description:

Effect of roughness on frictional force in Friction - Class 8 Science Experiment

This experiment aims to investigate the effect of surface roughness on the frictional force acting on an object moving down an inclined plane.

Two different surfaces, i.e., a horizontal floor and a cloth spread over the floor, will be used to observe the variations in the distance covered by a pencil cell (or ball) as it moves down the inclined plane.

Required Items:

  1. Wooden board (to create the inclined plane)
  2. Pencil cell or ball
  3. Cloth (smooth and wrinkle-free)
  4. Measuring tape or ruler

Step by Step Procedure:

  1. Set up the wooden board as an inclined plane on the horizontal floor.
  2. Mark a point “A” on the inclined plane.
  3. Release the pencil cell (or ball) from point “A” and let it move down the inclined plane.
  4. Measure the distance covered by the pencil cell from the bottom of the inclined plane to the point where it comes to a stop. Record this distance as “Distance 1.”
  5. Now, spread the smooth cloth over the floor, ensuring there are no wrinkles.
  6. Repeat step 3 with the pencil cell, releasing it from point “A” on the inclined plane.
  7. Measure the distance covered by the pencil cell and record this distance as “Distance 2.”

Experiment Observations:

  1. Distance 1 (on the horizontal floor) and Distance 2 (on the cloth surface) will be recorded.
  2. Distance 2 will typically be shorter than Distance 1.


  1. Ensure the inclined plane is stable and securely placed.
  2. Keep the starting point (point “A”) consistent for both trials.
  3. Smooth out any wrinkles on the cloth to ensure uniformity of the rough surface.
  4. Use the same type and size of pencil cell or ball for accurate comparisons.

Lesson Learnt from Experiment:

The experiment demonstrates that the roughness of a surface has a significant impact on the frictional force experienced by a moving object. Smoother surfaces result in less friction, allowing the object to cover a greater distance before coming to a stop. On the other hand, rougher surfaces increase friction, leading to a shorter distance covered by the moving object.

This understanding is essential in various real-life scenarios, such as designing efficient transportation systems, selecting appropriate materials for different applications, and improving the performance of moving parts in machines.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *