Page 108 - ICSE Science 3 : E-book
P. 108
QUICK LOOK
1. Water is important for life on earth.
2. The change of state of water occurs because of changes in temperature.
3. Water keeps on changing its form continuously in nature through evaporation and
condensation.
4. The water cycle is the way through which water moves all around the earth.
5. Water that is available on the earth is not pure and fi t for direct use. It may contain
either soluble or insoluble impurities in it.
6. Impure water can be cleaned or purifi ed before use by fi ltration, boiling and
chlorination methods.
7. Rainwater harvesting is done to conserve water for later use.
EXERCISES
A. Fill in the blanks.
1. ____________ is opposite of evaporation process.
2. When the clouds get heavy with water drops, it falls down in the form of
____________.
3. Mud, dust and sand are some examples of ____________ impurities.
4. Drinking impure water can lead to ____________ diseases.
5. Germs present in water can be killed by adding ____________ to it.
B. Write (T) for true and (F) for false statements.
1. Evaporation is the process where water changes into ice on heating.
2. Impure water should be cleaned or purifi ed before use.
3. Rooftop harvesting is a method of collecting rainwater.
4. Human activities like washing in rivers make them fi t for use.
5. Stored rainwater can be used for both indoor and outdoor activities.
C. Answer the following in one word.
1. Process of purifying water by adding chlorine to it ____________
2. Substances that make something dirty or impure ____________
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