A ‘grain’ or a ‘blob’ is a ‘bit’
of a substance. Each ‘bit’ is a group of
billions of particles. We can see ‘bits’
but not individual particles.
When a grain of sugar dissolves, repeated collisions
with the water particles make the sugar particles separate
and become mixed up with the water particles.
The animation represents a ‘time lapse’
sequence of snapshots, showing this happening.
The sugar is still ‘there’, but we can’t
see it because we can only see groups containing large
numbers of particles: we can’t see individual
particles.
