Shadows – Shadow Patterns and their Formation

Introduction:

Almost all objects form a shadow of different shapes and sizes at different instances depending upon various factors. In this section, we are going to answer the following questions.

• What is a shadow? How is it formed?
• Does the shadow of an object change its position?
• Does the shadow of an object change its size?

Explanation:

Shadows and Their Formation:

An object is seen only when light falls on it, and it reflects some light into our eyes. However, objects block/reflect a certain amount of light falling on them, which leaves a dark area behind them, called the shadow. The shape of a shadow resembles that of the object. However, it has no color. Its color is just shades of grey/darkness.

Fig 1: Shadow formation

Shadow Patterns:

The shadow of an object can be of different sizes and can be formed at different positions. This depends upon the position of the source of light. The source of light can be a torch, a tube light, the Sun, a flashlight, etc.

The position of a shadow depends upon the position of the light source, i.e., the direction of light. A shadow is always formed opposite the light source.

If the light source is towards the right of the object, its shadow is formed towards its left and vice versa. Similarly, if the light source is towards the top of the object, its shadow is formed at its bottom, and vice versa.

Fig 2: Positions and sizes of the shadow as per the positions of the light source

Shadows can also be formed in various sizes. This too depends upon the position of the light source.

For example, during sunrise and sunset, our shadow is the longest in size. However, as the Sun goes up, the size of the shadow decreases and becomes the shortest at noon when the Sun is overhead. The size of the shadow then goes on, increasing again when the Sun goes down.

Questions and Answers:

By looking at the shadow size in the picture, identify the time of the day among early morning/evening, noon, mid-morning, etc.

C.

Answer:

1. Sunrise/sunset
2. Mid-day
3. Noon

Summary

• Objects block a certain amount of light falling on them, which leaves a dark area behind them, called the shadow.
• A shadow is always formed opposite to the light source.
• During sunrise and sunset, a shadow is the longest in size.
• However, as the sun goes up, the size of the shadow decreases and becomes the shortest at noon when the sun is overhead.