Shadow Formation Notes & Questions | Class 3 Physics | Drishti OS

Shadow Formation

What you'll learn

A shadow forms when an opaque object blocks light from passing through it.
Shadows are usually darker and clearer on a sunny day than a cloudy day.
The length of a shadow changes as the Sun's position changes during the day.
Shadows look longer in the early morning and evening, and shorter near midday.
A shadow copies the outline (shape) of the object blocking the light.

Key concepts

Level 1 — Core idea

Verbal: A shadow is a dark shape formed on a surface when an object blocks the path of light.

Symbolic: light source + opaque object + surface = shadow

Visual: Stand in the Sun in the morning and again at noon — your shadow is longer in the morning and shorter at noon.

Level 2 — Going deeper

Think about where you see this idea in daily life at home and school — noticing it around you makes the concept easier to remember.

NCERT anchor

NCERT Looking Around 3 shadow-play activities show how children trace their own shadow at different times of day.

Worked example

Why is your shadow long in the early morning but short at noon?

Step 1 — The Sun is low in the sky in the morning
Step 2 — A low Sun makes shadows **stretch out longer**
Answer: **Shadow is longest in the morning, shortest near noon**

You hold a round ball between a torch and a wall. What shape appears on the wall?

Step 1 — The ball blocks the torch's light
Step 2 — The shadow **copies the ball's round outline**
Answer: **A round shadow shape appears on the wall**

Common mistakes

Mistake	Why	Fix
Shadows stay the same size all day	Not observing the Sun's changing position	Shadow length changes through the day
Shadows form without any light	Missing the need for a light source	A shadow needs light blocked by an object
Shadows show true colours	Confusing shadow with a photo	A shadow is usually just a dark outline
Cloudy days give the sharpest shadows	Reversing sunny and cloudy	Sunny days usually give clearer, sharper shadows

Quick check

What causes a shadow to form?
When is your shadow the longest during the day?
Does a shadow show the object's colours?
Stretch: Why do shadows disappear at night?

Revision tip: Picture the Sun's position in the sky before deciding if a shadow is long or short.

Open the Practice tab for graded questions on Shadow Formation.

Shadow Formation