Page 100 - Viva ICSE Science 5 : E-book

ACTIVITY TIME

To show when the work is done and when it is not done
You Need:

A desk, a chalk
What to Do:

• Using the chalk, draw a mark A on the current position of the
desk.
• Push the desk by applying some force.
• Now observe if the desk has moved some distance away from
the mark A.
If the desk has moved away from its initial position as a result of the
force applied on it, the work is said to be done.
• Next, choose any of the four walls of the classroom and try to
push it by applying some force.

The wall doesn’t move from its place. Thus, the work is not done in
this case.

Energy

We know that to do work, energy is needed. Your parents tell you to eat proper food
because food gives you enough energy to work. Energy is defi ned as the ability to do
work, i.e., it provides you the force with which you can do work.

Sun is the main source of energy. Plants use light energy from sun rays to grow and
produce food for us. We get energy by eating plant and animal products. Plant products

include fruits, vegetables and cereals. Animal products include dairy products like milk,
cheese and curd, eggs and meat.

We use energy in diff erent ways. Some examples are as follows.
• To play outdoor games like football and cricket

• To clean our rooms
• To walk, run, jump and swim

TIME TO REVISE

Fill in the blanks.

1. To do work we need _________.
2. _________ gives you enough energy to work.

3. We get energy by eating _________ and _________ products.

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