Page 50 - York Global Science 6 - Physical Science
P. 50
A scientist called Robert Brown discovered that individual particles move
within a substance.
Robert Brown (1773–1858) Microscope from about 1800
Robert Brown was looking through a microscope at pollen grains (small
objects) suspended in water. He saw that the pollen grains were moving,
even though they were not alive. He thought that the water molecules around
the pollen grains were moving and that when they collided with the pollen
grains, the pollen moved.
The movement that happens
when particles collide with other
particles and make them move is
called Brownian motion. The name
comes from the scientist who first
discovered it.
Brownian motion makes a random
pattern of movement, with each
particle moving in its own way.
Think!
What might make the particles move faster or slower?
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