A.
1. d. 2. d. 3. a. 4. b. 5. c
B.
1. Solid, liquid
2. evaporation, precipitation
3. equator, poles
4. mountain, range
5. moon, sun
C.
1. T 2. T 3. F 4. F 5. T
D.
1. b. 2. d. 3. e. 4. a. 5. c.
E. Short Answer Type Questions
1. Define the water cycle.
The process by which water continuously changes its form and circulates between the oceans, atmosphere, and land is known as the water cycle. In this process, water evaporates due to the heat of the Sun, forms clouds, falls as rain or snow, and finally collects again in rivers, lakes, oceans, and underground.
2. How is water distributed on Earth?
Water covers about 71% of the Earth’s surface. Nearly 97% of the total water is found in oceans and seas and is salty. Only about 3% is fresh water, most of which is stored in glaciers and ice caps, while a small amount is available in rivers, lakes, and groundwater for human use.
3. Name the inland water bodies that are used for transportation.
The main inland water bodies used for transportation are rivers, lakes, and canals. They are used to transport goods and passengers at a lower cost.
4. How does groundwater get collected?
Groundwater is collected when rainwater and surface water seep into the soil and move downward through cracks and pores of rocks. This water gathers underground in spaces called aquifers and is obtained through wells and tube wells.
5. How are waves formed?
Waves are mainly formed due to the blowing of winds over the surface of seas and oceans. Strong winds transfer energy to water, causing it to rise and fall in the form of waves. Sometimes underwater earthquakes also produce very large waves called tsunamis.
F. Long Answer Type Questions
1. The distribution of freshwater depends on climatic conditions and is highly uneven. Explain with an example.
Freshwater distribution on Earth is not equal because it mainly depends on rainfall and climatic conditions. Regions receiving heavy rainfall have plenty of freshwater, while dry regions suffer from shortage of water.
For example, areas like the Amazon Basin receive heavy rainfall and have many rivers and forests. On the other hand, desert regions such as the Sahara Desert receive very little rainfall and face water scarcity. Thus, freshwater distribution is highly uneven across the world.
2. How are glaciers formed? Give an example.
Glaciers are formed in very cold regions where snowfall occurs throughout the year. The fallen snow does not melt completely and keeps accumulating layer by layer. Over time, the snow gets compressed into thick masses of ice which slowly move downward under their own weight. This moving mass of ice is called a glacier.
Examples include glaciers found in the Himalayas, such as the Gangotri Glacier.
3. What factors cause horizontal and vertical movement of ocean water?
Ocean water moves both horizontally and vertically due to several factors. Horizontal movement mainly occurs because of winds, rotation of the Earth, and differences in temperature and salinity.
Vertical movement happens due to differences in density of water, which are caused by variations in temperature and salt content. Cold and salty water is heavier and sinks, while warm water rises, causing vertical circulation.
4. Define wavelength. What factors decide the size of waves?
Wavelength is the horizontal distance between two successive crests or two successive troughs of a wave.
The size of waves mainly depends on:
• Speed of the wind
• Duration for which the wind blows
• Distance over which the wind blows across the water surface
5. Define tide. How is it influenced by the gravitational force of the Sun and Moon?
A tide is the regular rise and fall of ocean water level caused mainly by the gravitational pull of the Moon and the Sun on Earth.
The Moon has a stronger effect because it is closer to Earth. When the Moon and Sun pull the ocean water, it rises and causes high tide. When their pull is weaker, water level falls, causing low tide.
G. Distinguish Between
1. Waves and Tides
| Waves | Tides |
|---|---|
| Formed mainly due to wind. | Caused by gravitational pull of Moon and Sun. |
| Occur continuously. | Occur at regular intervals. |
| Affect only surface water. | Cause rise and fall of sea level. |
2. Crest and Trough
| Crest | Trough |
|---|---|
| Highest part of a wave. | Lowest part of a wave. |
| Formed when water rises. | Formed when water falls. |
3. Evaporation and Condensation
| Evaporation | Condensation |
|---|---|
| Water changes into vapour due to heat. | Water vapour cools and changes into droplets. |
| Occurs due to heating. | Occurs due to cooling. |
4. High Tide and Low Tide
| High Tide | Low Tide |
|---|---|
| Water level rises. | Water level falls. |
| Occurs due to strong gravitational pull. | Occurs when gravitational pull is weaker. |
H. Give Reasons
1. Tides are considered important.
Tides help in navigation, fishing activities, and cleaning of coastal areas. They also help ships enter and leave harbours safely.
2. Fog over the ocean is considered dangerous for ships.
Fog reduces visibility, making it difficult for ships to see other ships, rocks, or land, which increases the risk of accidents.
3. Ships prefer to sail with the current.
Ships move faster and save fuel when they sail in the direction of ocean currents. It makes travel easier and more economical.
4. Ocean water is salty.
Ocean water is salty because rivers carry dissolved salts and minerals from land into the oceans over thousands of years. The water evaporates, but the salts remain behind, making ocean water salty.