NCERT Solutions for Class 5th The World Around Us Chapter 9 How long does a change take? — Write
Book page 148–149 Updated on2026-09-19
Q1.
1. Can you think of something that takes a really long time to change, maybe over years?
Answer
A big tree. A banyan or a mango tree takes many, many years to grow tall and thick. If you see it every day you notice nothing at all. Come back after ten years and you cannot believe it is the same tree.
Other things that change only over years:
Mountains and rocks. Wind and rain wear them down grain by grain. It takes thousands of years.
A river's path. A river slowly cuts its bank on one side and drops sand on the other, so its bend keeps shifting.
A coastline. The sea eats away the shore very slowly.
A person growing up. A baby becomes a school child, then a grown-up.
A village becoming a town. New houses, new roads and new shops come up one by one.
A tortoise's size. A tortoise can keep growing for fifty years or more.
Why we do not notice these: The change in one day is far too small for our eyes to catch. Only when a lot of tiny changes add up over years does the difference become big enough to see. That is why a photograph is so useful — it holds one day still so you can compare it with today.
Try this: Stand against a wall and get someone to mark your height with a pencil. Mark it again after six months. The gap between the two lines is a change that was happening every single day without you feeling it.
Q2.
2. What about something that changes within just a few years?
Answer
A sapling you plant in the school ground. In two or three years it is taller than you and starts giving shade.
Some more changes that take only a few years:
What changes
In about how long
How you can tell
A puppy
1–2 years
It becomes a full-grown dog
A papaya or banana plant
1–2 years
It starts giving fruit
A calf
3–4 years
It becomes a cow that gives milk
Your milk teeth
2–3 years
They fall out and new, bigger teeth come
Your school uniform
1–2 years
It becomes short and tight
A new road or bridge
2–3 years
It is finished and buses begin to use it
Your reading
2–3 years
You go from picture books to story books
Why these are faster: Living things that have a short life grow quickly — a puppy has to become an adult dog in about a year, so it changes fast. A banyan tree lives for hundreds of years, so it can afford to grow slowly.
Q3.
3. Are there changes that happen every year, again and again?
Answer
Yes — the seasons. Summer, then the rains, then winter, and then summer again. This happens every single year, always in the same order. That is why we call it a rhythm of nature.
Other changes that come back every year:
Trees shedding and growing leaves. Old leaves fall in autumn and pre-winter; new leaves come out in spring.
Flowering. The mango tree flowers in February–March. The gulmohar flowers in summer. The marigold flowers around Diwali.
Fruits. Mangoes and litchis in summer, guavas in winter — every year at the same time.
Birds arriving and leaving. Migratory birds like cranes and ducks come to our lakes in winter and fly back when it gets warm.
The koel calling. It starts calling again as spring comes.
Crops. Paddy is sown in the rains and wheat in winter, year after year.
Festivals. Pongal in January, Holi in spring, Diwali in autumn — they follow the seasons, so they come back too.
Your birthday. It comes once every year, because that is how long the Earth takes to go once round the Sun.
Why they repeat: The Earth takes one year to go once round the Sun. When the round trip is over, everything is back where it started, so the same weather returns and nature does the same things again. This is why we can say with confidence what the weather will be like next June.
Q4.
4. Can you name something that changes in just a few minutes or even seconds?
Answer
The colour of the sky at sunset. In a few minutes it goes from blue to orange to pink to grey.
Things that change very fast:
What changes
How fast
What happens
A soap bubble
A few seconds
It floats up, wobbles and bursts
A lightning flash
Less than a second
The whole sky lights up and goes dark again
Ice in your hand
A few minutes
It melts into water
A hot chapati
A few minutes
It becomes cool enough to eat
Clouds on a windy day
A few minutes
They change shape and cover the Sun
Your face
A second
It changes from serious to smiling
A touch-me-not (chhui-mui) leaf
A second
It folds up as soon as you touch it
Water on a hot tawa
Seconds
It hisses and disappears as vapour
Seconds → a bubble bursting Minutes → ice melting Days → a seed sprouting Months → a season passing Years → a tree growing tall Thousands of years → a mountain wearing down
What all four questions together teach us: Change is not one single thing. It comes at many different speeds. Some changes we can watch happening; some we can only see by comparing today with a photograph; and some are so slow that no one person can ever see them finish.