How Light Travels - Teacher Explanation

The "Three Holes and a Torch" activity is designed to demonstrate the nature of light travel to students. In this experiment, teachers instruct pupils on how to confirm that light travels in straight lines rather than bending. To perform the experiment, students require scissors, a torch, cardboard, and clothes pegs. The experiment involves aligning four pieces of cardboard with holes punctured in the same relative position and using a torch to shine light through these holes. The light should appear as a blob on a larger piece of card, acting as a screen. When the middle cardboard piece is shifted and the holes are misaligned, the blob of light disappears, indicating that the light path is blocked and affirming that light does not bend around objects.

Another activity, "The Tube and the Candle," aims to dispel the misconception that light emanates from our eyes, allowing us to see. Instead, it demonstrates that light must first strike an object and then enter our eyes. This is shown using a tube and a tea light candle. By observing the candle through the tube and then moving it to the side, students can see that the candle disappears from view, reinforcing the concept that light travels in straight lines and does not bend into the tube. This activity, along with tasks on classifying objects as luminous or non-luminous and creating ray diagrams, helps students understand the fundamental properties of light and how we perceive it.