Chapter 15, Problem 2RQ

What was the source of motion in the particles that Brown investigated?

To determine

The source of motion in the particles that Brown investigated.

Answer to Problem 2RQ

The source of motion in the particles that Brown investigated was the collision between invisible atoms and the visible particles.

Explanation of Solution

The first direct proof for atoms was invented by a Scottish botanist Robert Brown. While studying about pollen in a drop of water with the help of a microscope, he observed that the grains were continually moving about.

This perpetual jiggling of particles is called Brownian movements. These were the result of a collision between invisible atoms and visible particles. Brown’s pollen grains start moving because they were constantly being jostled by groups of atoms that make up the water.

Conclusion:

Therefore, the source of motion in the particles that Brown investigated was the collision between invisible atoms and the visible particles.