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:
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:
- Wooden board (to create the inclined plane)
- Pencil cell or ball
- Cloth (smooth and wrinkle-free)
- Measuring tape or ruler
Step by Step Procedure:
- Set up the wooden board as an inclined plane on the horizontal floor.
- Mark a point “A” on the inclined plane.
- Release the pencil cell (or ball) from point “A” and let it move down the inclined plane.
- 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.”
- Now, spread the smooth cloth over the floor, ensuring there are no wrinkles.
- Repeat step 3 with the pencil cell, releasing it from point “A” on the inclined plane.
- Measure the distance covered by the pencil cell and record this distance as “Distance 2.”
Experiment Observations:
- Distance 1 (on the horizontal floor) and Distance 2 (on the cloth surface) will be recorded.
- Distance 2 will typically be shorter than Distance 1.
Precautions:
- Ensure the inclined plane is stable and securely placed.
- Keep the starting point (point “A”) consistent for both trials.
- Smooth out any wrinkles on the cloth to ensure uniformity of the rough surface.
- 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.
