Question

When extremely small particles X derived from the anther of a flower were suspended in a liquid Y and observed through a microscope, it was found that the particles X were moving throughout the liquid Y in a very zig-zag way. It was also observed that warmer the liquid Y, faster the particles X moved on its surface.
(a) What could particles X be ?
(b) What do you think liquid Y is ?
(c) What is the zig-zag movement of X known as ?
(d) What is causing the zig-zag movement of particles X ?
(e) Name the scientist who discovered this phenomenon.
(f) What does this experiment tell us about the nature of liquid Y?

Answer 1

(a) The particles, 'X' are pollen grains.
(b) The fluid, 'Y' is Water.
(c) The zigzag movement of 'X' is called Brownian motion.
(d) The zigzag motion of the pollen grains occurs because the particles of water are in constant motion. These particles collide with the pollen grains and cause them to move.
(e) Robert Brown is the scientist who discovered Brownian motion.
(f) Liquid Y is made up of extremely small particles, which are moving constantly.