HARD
Earn 100

Let us conduct an activity to know that the air has weight.

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Take a stick of 50 cm length. Tie an air filled balloon to one of its ends and an empty balloon to the other end. Tie a thread at the exact center of the stick as shown in the picture and hold it freely. What do you observe? 

Important Questions on Changes Around Us

EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Which of the following is not an example of a biomass energy source?
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Name two uses biogas.
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Write down the process of evolution of fossil fuels on Earth.
MEDIUM
Science>Chemistry>Changes Around Us>Classification of Changes
Write a short note on: Nuclear Energy
MEDIUM
Science>Chemistry>Changes Around Us>Classification of Changes
Explain how is nuclear energy generated in power reactors. How is electricity produced from nuclear energy?
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
By what name is biogas popularly known in India?
MEDIUM
Science>Chemistry>Changes Around Us>Classification of Changes
List any three differences between nuclear fission reaction and nuclear fusion reaction.
MEDIUM
Science>Chemistry>Changes Around Us>Classification of Changes
Useful substance in preparation of freezing mixture is 
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Uranium is used to obtain:
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Which of the following is not an example of a bio-mass energy source?
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
 State two ways to prevent the rusting of iron.
EASY
Science>Chemistry>Changes Around Us>Classification of Changes

Write names of any two energies produced in ocean.

MEDIUM
Science>Chemistry>Changes Around Us>Classification of Changes

Which of the following are physical changes?

(a) Melting of iron metal        (b) Rusting of iron

(c) Bending of an iron rod     (d) Drawing a wire of iron metal

EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Write the name of two elements used as nuclear energy.
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Which one of the following is an example of Biomass energy source.
MEDIUM
Science>Chemistry>Changes Around Us>Classification of Changes
Write any four differences between nuclear fusion and nuclear fission.
EASY
Science>Chemistry>Changes Around Us>Classification of Changes
Nowadays bio-diesel is used in transportation vehicles as an alternate to diesel. Write two advantages of this measure.
EASY
Science>Chemistry>Changes Around Us>Classification of Changes

Write down the two benefits of use of solar energy.

HARD
Science>Chemistry>Changes Around Us>Classification of Changes
Seema bought a new skirt for school. When she came home, she realised that it was too long, so she asked her mother to hem it. What kind of change is this?
MEDIUM
Science>Chemistry>Changes Around Us>Classification of Changes
Why cannot permanent change be reversed? When milk is turned into curd, its taste changes. Why? Can we change the curd back into milk?