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

## 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:

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

### Step by Step Procedure:

1. Observe the paths (ACB, ADB, AEB, and AFB) in Figure-3.
2. Create duplicates of these paths (ACG, ADG, AEG, and AFG) in Figure-4.
3. 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:

1. Ensure the accuracy of measurements during the comparison of path lengths.
2. 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.