Pollen grains suspended in water are observed under a microscope.
How do the pollen grains move when undergoing Brownian motion?
in a random, jerky path
in expanding concentric circles
in a single, constant direction
vibrating about fixed points
321 exam-style questions on CIE IGCSE Physics 2.1 Kinetic particle model of matter, covering 2.1.1 States of matter and changes of state, 2.1.2a Particle structure and motion in solids, liquids and gases, 2.1.2b Gas pressure and particle collisions, 2.1.2c Brownian motion, 2.1.3a The absolute scale of temperature, and 2.1.3b Pressure, volume and temperature of a gas. Each one has a worked solution and a mark scheme showing where the marks go.