In an experiment to demonstrate Brownian motion, tiny pollen grains are suspended in water and viewed through a microscope. The pollen grains are observed to make short, random, jerky movements. Which of the following statements is correct?
Water molecules have larger masses compared to pollen grains and they move in one direction only.
Water molecules have larger masses compared to pollen grains and they move in random directions.
Water molecules move at lower speeds compared to pollen grains and they move in one direction only.
Water molecules move at higher speeds compared to pollen grains and they move in random directions.
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.