How do we know that light travels in a straight line? - Diagram and Graph - Year 6

In a Year 6 educational setting, students explore the fundamental concept that light travels in a straight line. To support their learning, graphs or diagrams are employed to provide visual evidence and clarification. These educational tools help illustrate the journey of light and how it behaves. For instance, a common demonstration might involve a light source, such as a torch or a candle, and a series of obstacles with straight edges. By observing the shadows cast by these objects, students can infer that the light must be travelling in straight lines, as the edges of the shadows are also straight and align with the direction of the light source.

Additionally, the human eye plays a crucial role in understanding the nature of light's travel. Through various experiments and observations, students learn how the eye receives light and forms images. When looking at objects, the light that reaches our eyes has travelled in a direct path from the source to the object and then to our eyes, allowing us to see the object clearly. This observation further reinforces the concept that light travels in straight lines. By engaging with these visual aids and practical experiments, students can grasp the fundamental principles of light's linear propagation.