Wonders of Light

This week in KS3, children have been learning about properties of light, particularly reflection and refraction. Through videos, practical activities and discussions, they have discovered and understood some of these properties in greater depth.

To understand refraction, children placed a ruler in water, which made it appear bent. They also drew two arrows facing the same direction on a piece of paper. They then placed this behind the clear glass with water in it, and observed that the arrows appeared to face the opposite direction. They deduced that the light rays were bent as they travelled from a less dense medium (air) to a more dense medium (water), creating the illusion of a bent ruler or arrows facing in the opposite direction.

The children explored total internal reflection by pointing a laser light through a clear beaker of water. They observed that when the ray of light is more than 90 degrees to the line of normal, the ray of light appears as if its been reflected off the water surface into the same region as the source of light. It looked like as if it was reflecting but it was actually refraction.

They also learnt about dispersion of light by observing what happens when you shine white light through a prism. They noticed that the white light was split up into seven constituent colours, forming the rainbow colours. They learnt that the seven colours are due to the fact that different colours travel at different speeds and are bent at different angles when they pass through the prism or water droplets (denser medium).

The lessons have been very engaging and enriched with opportunities to share personal experiences and, of course, light-bulb moments.