From NCERTAsked by Anonymous from Frankfurt, Germany24 Oct 2026, 11:04 AM ISTUpdated
In one line
Shadows change in size and direction during the day because the Sun moves across the sky.
Sundial — Time-telling device A sundial uses the changing shadow of a stick to tell the time of day. Image: Wikipedia
The rule
Shadows are formed when an object blocks light, and their size and direction depend on the position of the light source (like the Sun).
Let's understand it simply
Imagine you are playing cricket in your school ground. Early in the morning, your shadow is very long and points towards the west. At noon, when the Sun is right above you, your shadow becomes very short and is just below you. In the evening, your shadow grows long again, but now it points towards the east. This happens because the Sun appears to move from east to west in the sky, and your shadow always forms on the side opposite to the Sun.
How it works
The Sun rises in the east. Shadows are long and point west.
As the Sun climbs higher, shadows get shorter.
At noon, the Sun is almost overhead. Shadows are shortest and just below the object.
After noon, the Sun moves towards the west. Shadows grow longer again and point east.
At sunset, shadows are longest, stretching far to the east.
How a shadow changes during the day
Morning: Sun in east, shadow long and to the west
Noon: Sun overhead, shadow short and under you
Evening: Sun in west, shadow long and to the east
The story behind it
People have noticed changing shadows for thousands of years. Ancient Indians used shadows to tell time with sundials (a stick in the ground). The shadow’s length and direction helped them know the hour. This simple idea led to the first clocks!
Where you see it in real life
In the playground: Your shadow changes length and direction as you play throughout the day.
Under a tree: The shade moves, so you keep shifting your mat to stay cool.
On the road: Electric poles cast long shadows in the morning and evening, but short ones at noon.
At home: The shadow of your house moves, so some rooms get sunlight at different times.
During festivals: Rangoli or Diwali lamps look different as their shadows change with the Sun.
Why it matters
Sundials and old clocks use shadows to tell time.
Farmers use shadow changes to know the best time to sow or harvest crops.
Architects plan buildings so rooms get sunlight at the right times.
Understanding shadows helps in photography, art, and even cricket (fielding positions).
Common mistakes
Thinking the Sun actually moves around the Earth. (It’s the Earth that rotates, but it looks like the Sun moves.)
Believing shadows are always the same size. (They change with the Sun’s position.)
Forgetting that artificial lights at night can also make shadows, but these don’t change like the Sun’s shadows.
Remember it
Sun low, shadow long. Sun high, shadow short. Shadow always points away from the Sun.
Check yourself
Why is your shadow longest in the morning and evening?
Because the Sun is low in the sky, so the light hits you from the side.
At what time of day is your shadow shortest?
At noon, when the Sun is almost overhead.
If your shadow is pointing east, where is the Sun?
The Sun is in the west, because shadows point away from the Sun.
Why do shadows change direction during the day?
Because the Sun’s position in the sky changes as the Earth rotates.
Quick recap
Shadows change size and direction as the Sun moves across the sky.
Morning and evening shadows are long; noon shadows are short.
Shadows always point away from the Sun.
People used shadows to tell time before clocks were invented.
