Page 151 - Science Class 06

Freezing point : The temperature at which a liquid turns into a solid when cooled
Water cycle : Continuous circulation of water on the earth

Lightning : Sparkle of light caused due to the transfer of charges from one cloud to
another or to the earth

Let's R
Let's R
Let's Revise evise evise evise evise evise evise
Let's R
Let's R
Let's R
Let's R
i Water is found in all the three physical states— solid, liquid and gas.
i Evaporation takes place on heating a liquid.
i Condensation takes place on cooling a liquid.
i All the three states of water are interchangeable.
i Water boils at 100°C.

i Thundering and lightning are caused due to transfer of charge from one cloud to another or
to the earth.
i A cloud may have both negative and positive charges.
i Water cycle is a continuous process of water on the earth.

Exerciseerciseerciseerciseerciseercise
Ex
Ex
Ex
Ex
Exercise
Ex
A. Tick ( ) the correct op on. 3
1. Warm air rises upward because:
(a) warm air is less dense than cold air.

(b) warm air is more dense than cold air.
(c) warm air as dense as cold air.
(d) none of these.
2. In which of the following climate condi ons water cycle goes slow?

(a) Very cold (b) Dry
(c) Cold (d) None of these
3. Boiling point of water is:

(a) 150°C (b) 50°C
(c) 100°C (d) 60°C
4. What should not be done while it is lightning in the sky?
(a) Standing under a tall building (b) Adjus ng antennae of the television

(c) Walking in the fields (d) All of them
5. The temperature at which a liquid turns in solid is called:
(a) freezing point (b) boiling point
(c) mel ng point (d) none of these

Science-6 151