# Path of light to travel in Reflection of Light By Different Surfaces – Class 10 Science Experiment

**Chapter Name:** Reflection of Light By Different Surfaces

**Activity Name:**** **Path of light to travel **in **Reflection of Light By Different Surfaces

**Activity Description:**

In this experiment, we will analyze the path taken by a smart crow to pick up a grain from point A on the ground and reach point B on another tree in the least possible time. By using mathematical knowledge about angles and triangles, we will determine the shortest path the crow selects.

**Required Items:**

- Figure-2: Illustration of a smart crow on a tree at point A with grains on the ground and point B on another tree.
- Figure-3: Illustration of different paths (ACB, ADB, AEB, and AFB) the crow can take from point A to point B.
- Figure-4: Illustration of duplicate paths (ACG, ADG, AEG, and AFG) used to compare lengths of paths.

**Step by Step Procedure:**

- Observe the paths (ACB, ADB, AEB, and AFB) in Figure-3.
- Create duplicates of these paths (ACG, ADG, AEG, and AFG) in Figure-4.
- Compare the lengths of the duplicate paths with their corresponding original paths (e.g., ACG vs. ACB, ADG vs. ADB, etc.).

**Experiment Observations: **

- The length of path ACB is equal to the length of path ACG.
- Similarly, the length of path ADB is equal to the length of path ADG.
- The length of path AEB is equal to the length of path AEG.
- The length of path AFB is equal to the length of path AFG.
- From the observations, it is found that among the paths ACG, ADG, AEG, and AFG, the shortest path is AEG, which represents the straight-line distance between points A and G.

**Precautions:**

- Ensure the accuracy of measurements during the comparison of path lengths.
- Use a scale or measuring tool to validate the length of each path.

**Lesson Learnt from Experiment:**

The experiment demonstrates the principle that both smart crows and light choose the path that takes the least time to travel. This principle was first given by Pierre de Fermat, a French lawyer and an amateur mathematician.