Ball Bearing Experiment

        A machine that works requires energy. Part of the energy is lost due to friction. Friction is a force that opposes motion. It is caused by the moving parts of a machine when they rub against each other. Reducing friction allows machines to run smoothly and efficiently and consume less fuel and energy. Bearings are supports that reduce friction. They help a moving part to roll rather than rub on its support. It consists of small metal balls over which the rotating part rolls over.

Ball Bearing Experiment

Let us build a simple ball bearing and see how it enables objects to spin easily.

Things we need

2 jar lids (one of which closely fits into another), marbles/ metal balls, pencil, clay, A wooden block, sticky tape.

Step 1 : Stick the smaller jar lid upside down on a wooden block.

Step 2: Place two equal blocks of clay on the ends of the pencil and stick the middle of the pencil to the larger lid.

Step 3 : Put the larger lid over the smaller lid and spin it sharply. Note how long it spins.

Step 4 : Remove the top lid and put marbles into the smaller lid. There should be enough marbled to form a ring and they should be able to move freely. Now replace the larger lid over the smaller lid and spin the pencil sharply. Note how long it spins. 

Observation

We observe that the pencil spins faster and longer when the two lids are separated by marbles. Thus the marbles or metal balls act as ball bearings and reduce friction between the rotating top lid and its support. Here is an example where ball bearing is put to practical use.

 Ball Bearing Experiment Video