The spreading of the scent of a flower in a garden is an example of_____?

Step 1: Analyze the question The question asks what process explains how the scent of a flower spreads through the air in a garden.

Step 2: Explain the concept Flower scent is made of gas or vapour molecules. Gas molecules move randomly and spread from a region of high concentration (near the flower) to regions of low concentration (the surrounding air). This is called diffusion.

Let's check each option:

• A. Brownian motion: the random, zigzag movement of visible colloidal particles (such as pollen grains or smoke) caused by collisions with fast-moving molecules of the surrounding medium. It is not the spreading of a scent.
• B. Diffusion: the movement of particles from a region of higher concentration to a region of lower concentration until they are evenly distributed. This matches the scent spreading.
• C. Osmosis: the movement of water (solvent) through a semi-permeable membrane from a dilute solution to a more concentrated one. No membrane is involved here.
• D. Tyndall effect: the scattering of light by colloidal particles, which makes a light beam visible. It has nothing to do with spreading.

Step 3: Solution The scent molecules leave the flower, collide with air molecules, and gradually spread out in all directions from high to low concentration. This is diffusion.

Answer: B. Diffusion

Exam tip: Whenever you see examples like perfume spreading in a room, the smell of cooking reaching you from the kitchen, or a bromine vapour spreading in a gas jar, think diffusion. For Brownian motion, think "visible particles jiggling randomly." For osmosis, always look for a membrane and water.