Understanding the principle of ball bearings in Friction – Class 8 Science Experiment

Chapter Name: Friction

Activity Name: Understanding the principle of ball bearings in Friction

Activity Description:

Required Items:

1. Two circular lids (could be from containers or any flat circular objects)
2. Four to five marbles

Step by Step Procedure:

1. Take the two circular lids and ensure they are clean and dry.
2. Place one lid on a flat surface.
3. Take the second lid and place it on top of the first lid without any marbles in between.
4. Try to rotate the top lid clockwise and observe the ease of rotation and any resistance encountered.
5. Remove the top lid and place four to five marbles evenly spaced on the first lid.
6. Carefully place the second lid back on top of the marbles.
7. Attempt to rotate the top lid clockwise and observe the difference in rotation compared to the previous step.

Experiment Observations:

1. When two lids are stacked without marbles, there might be some resistance while rotating the top lid, and it may not rotate smoothly.
2. When marbles are placed between the two lids, the rotation of the top lid becomes much smoother and more effortless.

Precautions:

1. Ensure the lids and marbles are clean to avoid any interference caused by dirt or debris.
2. Handle the marbles with care to avoid any breakage or injury.

Lesson Learnt from Experiment:

The experiment illustrates the principle of ball bearings, where the marbles act as the ball bearings between the two lids. Ball bearings help in reducing friction between rotating shafts in machine tools, making their movement smoother and more efficient. This setup allows for minimal resistance and wear, which is essential for the proper functioning and longevity of machinery.