KSEEB Solutions Class 8 Geography Chapter 4 Hydrosphere Points To Remember
The Earth is popularly called ‘Blue planet’ or ‘ Watery planet’ because about 71 % of the total area of the earth or 361 million sq. km is covered by water. The major water bodies of the world are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic ocean. Oceans are deep and large expanses of water found between the continents.
A sea is a part of the ocean extended or projected far inland. Seas are smaller compared to oceans, For Example:- the Arabian sea, the Caspian sea, and the Red sea.
The gulf is a part of an ocean or sea that penetrated the land. It is smaller than a sea. The size, shape, and depth of a gulf vary from one to another, for Example:- the Gulf of Mannar, the Persian Gulf, and the Gulf of Mexico.
Read and Learn More KSEEB Solutions for Class 8 Social Science
Bays are small semi-circular water bodies partially surrounded by land. The depth, extent, and size of bays vary from one to another, Example:-the Bay of Bengal, the Bay of Biscay, the Bay of Fundy, and Hudson Bay.
A strait is a narrow strip of water body joining two large water bodies, Example:-Palk strait, the Strait of Gibraltar, or the Bering strait.
An isthmus is a narrow stretch of land mass joining two large land masses. The isthmus is the most important location for constructing ocean canals.
Kseeb Solutions For Class 8 Geography Chapter 4 Pdf
On the basis of the characteristic features, the ocean floor is divided into four major parts. They are:
- The continental shelf
- The continental slope
- The deep sea plain
- The ocean deeps The Deep sea plain is the vast plain found at the bottom of the sea floor. The deep sea plain is also known as the ‘abyssal plain’ and it covers the largest area of the ocean floor. In this region Sea mounts and Guyots are found.
The ocean deeps are also called ‘Ocean trenches’. These are the deepest part of the ocean floor. Sea or ocean water temperature varies according to latitudes and the depth of the ocean floor.
The temperature of the ocean water near the equator is more than that of the temperature near the Arctic and the Antarctic circles. With the increasing depth, the temperature of the ocean water decreases.
It is because the sunlight can penetrate into the ocean only up to a depth of 200 meters. Within this depth, various marine organisms are found in large numbers.
Ocean currents are the regular movement of ocean waters from one region to another, the two types of ocean currents are Warm and Cold ocean currents.
Factors that influence ocean currents are the Rotation of the Earth, Temperature, Wmd, Salinity Shape of the landmasses, etc.
Class 8 Geography Hydrosphere KSEEB Notes
Tides are the periodic rise and fall in the sea or ocean level. They occur due to, gravitational attraction by the moon, gravitational force by the sun, rotation of the earth, and, the centrifugal force of the earth.
There are two types of tides on the basis of the positions of the Moon and the Sun they are Spring tide and Neap Tide.
Kseeb Solutions Class 8 Geography Chapter 4 Notes
Hydrosphere Exercises
Fill in the blanks with suitable words:
- The average depth of the continental shelf is 100 fathoms
- One fathom is equal to 6 ft.
- The deepest place in the Pacific Ocean is Challenger deep.
- The average salinity of ocean water is 35 PPT.
- Spring tides occur during the foil moon.
Answer the following questions:
Question 1. What is a hydrosphere?
Answer: The part of the earth covered by water is called the hydrosphere.
Question 2. Mention the four major parts of the ocean floor.
Answer: The continental shelf, the continental slope, the deep sea plain, and the ocean deeps are the four major parts of the ocean floor.
Question 3. State the difference between ocean currents and tides.
Answer:
Ocean currents are the regular movement of ocean water from one region to another.
Warm currents and Cold currents are the two types of ocean currents.
Tides are the periodic rise and fall in the sea or ocean level.
Tides are of two types. High tide, also known as Floodtide, and Low tide, also known as Ebb tide.
Question 4. Distinguish between spring tide and neap tide.
Answer:
Spring tide: Spring tides take place when the earth, the moon, and the sun are in the same straight line, Example:- the New moon and Full moon. When the spring tides take place, high tides are the highest, and low tides are the lowest.
Neap Tide: Neap tides occur on the first quarter and last quarter days in the phase of the Moon. During neap tides, the sun and the earth are in the same straight line and the moon is at a right angle to the earth. In this type of tide, the high tides are not very high and the low tides are not very low.
Karnataka Board Class 8 Geography Chapter 4 Solutions
Question 5. How can we conserve the oceans?
Answer:
The following are the important methods of conservation of oceans.
Oil transportation should be done through pipelines.
Nuclear waste should not be dumped into the sea or ocean.
Petrochemical industries in coastal regions must avoid dumping effluents into the sea or ocean.
Dumping of any waste near the ports and harbors must be controlled.
Ore deposition and mineral exploitation along the coast must be controlled.
Exploitation and destruction of beaches must be controlled.
Hydrosphere Match the following:
A B
Fathom deep sea plain
Oyashio eastern coast of USA
Gulf stream cold current
Sea mounts Indian Ocean current
Agulhas current depth of the ocean
Answer:
A B
Fathom depth of the ocean
Oyashio cold current
Gulf stream eastern coast of the USA
Sea mounts deep sea plain
Agulhas current Indian ocean current
Hydrosphere Define the following:
Continental shelf: Continental shelf is the shallow area along the sea coast.
Salinity: Salinity is the percentage of salts dissolved in the sea or ocean water
Warm and Cold currents: The currents which originate and flow from the equatorial regions to sub-polar regions are Warm currents. The currents originate in the Polar Regions and flow towards the equatorial region are Cold currents.
High tide and Low tide: High tide, also known as Floodtide, and Low tide, also known as Ebb tide. On the water bodies of the earth, there are alternate high tides and low tides. Between one high tide and a low tide, the time is 6 hrs and 13 minutes. Between one high tide and another, the time-gap is 12 hrs and 26 minutes. In 24 hrs, 52 minutes there are 2 high tides and 2 low tides.
Benguela current: cold current in the South Atlantic ocean
Tides: Tides are the periodic rise and fall in the sea or ocean level.
Hydrosphere Terms to remember:
Gulf stream: Warm ocean current in the North Atlantic ocean
Salinity: Salinity is the percentage of salts dissolved in the sea or ocean water
Warm currents: The currents originate and flow from the equatorial regions to sub-polar regions.
Kuroshio current: warm ocean current in the North Pacific ocean
Flood tides: High tides are called Flood tides
Tidal energy: The energy produced using tides
Kseeb Class 8 Geography Chapter 4 Important Questions
Hydrosphere Additional Questions And Answers
Choose the correct alternative and Write the complete answer along with its alphabet in the sheet provided:
Question 1. The deep and large expanse of water found between the continents is
- Oceans
- Seas
- Gulf
- Bay
- Answer: 1. Oceans
Question 2. The ocean which is between Asia, Africa, and Australia is
- Pacific Ocean
- Indian Ocean
- Atlantic ocean
- Arctic Ocean
Answer: 2. Indian ocean
Question 3. The ocean which is between North America and Europe is
- Pacific Ocean
- Indian Ocean
- Atlantic ocean
- Arctic Ocean
Answer: 3. Atlantic ocean
Question 4. A part of the ocean extended or projected far inland is
- Strait
- Sea
- Gulf
- Bay
Answer: 2. Sea
Question 5. A part of an ocean or sea that penetrated into the land is
- Strait
- Seas
- Gulf
- Bay
Answer: 3. Gulf
Question 6. A narrow stretch of land mass joining two large land masses is
- Isthmus
- Strait
- Gulf
- Bay
Answer: 1. Isthmus
Class 8 Geography Chapter 4 Hydrosphere Kseeb
Question 7.The part of the ocean that is very important for aquaculture is
- The Deep sea plain
- The Continental slope
- The Continental shelf
- The Ocean deep
Answer: 3. The Continental shelf
Question 8. The second part of the ocean floor is
- The Deep sea plain
- The Continental slope
- The Continental shelf
- The Ocean deep
Answer: 2. The Continental slope
Question 9. The Submarine canyons are a special feature in
- The Deep sea plain
- The Continental slope
- The Continental shelf
- The Ocean deep
Answer: 3. The Continental shelf
KSEEB Geography Chapter 4 Class 8 Multiple Choice Questions
Question 10. In the equatorial region, the salinity is average due to
- Low evaporation and precipitation
- High evaporation and precipitation
- High temperatures and heavy rainfall
- Low temperature and heavy rainfall
Answer: 2. High evaporation and precipitation
Fill in the blanks with suitable words:
- The deep sea plain is also known as the ‘abyssal plain’
- The ocean deeps are also called ‘Ocean trenches’
- The deepest point of the ocean is Challenger deep
- The Seamounts and Guyots are found in Deep sea plain
Hydrosphere Answer the following questions in a sentence each:
Question 1. What is a Continental shelf?
Answer: Continental shelf is the shallow area along the sea coast. This part is bordered by the sea coast on one side and the continental slope on the other side.
Question 2. Why does the temperature change on the ocean floor?
Answer: Sea or ocean water temperature varies according to latitudes and the depth of the ocean floor.
Question 3. Why is sea water salty?
Answer: The water flowing from the land to the sea (river) carries many kinds of salts and deposits them in the sea or ocean. Due to high temperatures, water is evaporated continuously and the salts remain in the sea or ocean. This continuous process over a long period of time has resulted in the accumulation of salts in seawater.
Question 4. Which are the three types of movements of ocean water?
Answer: Waves, Currents, and Tides are the three types of movements of ocean water.
Kseeb Class 8 Geography Chapter 4 Hydrosphere Question Answers
Question 5. What are Tides? Mention its types.
Answer: Tides are the periodic rise and fall in the sea or ocean level. High tide and Low tide Spring tide and Neap Tide are the important tides.
Hydrosphere Answer the following questions in four to six sentences each:
Question 1. Why is the Earth popularly called the ‘Blue planet’?
Answer: The Earth is popularly called ‘Blue planet’ or ‘ Watery planet’ because about 71 % of the total area of the earth or 361 million sq. km is covered by water.
Question 2. Name the major water bodies of the world.
Answer: The major water bodies of the world are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic ocean.
Question 3. What is Bay? Give example.
Answer: Bays are small semi-circular water bodies partially surrounded by land. E.g. the Bay of Bengal, the Bay of Biscay, the Bay of Fundy, and Hudson Bay.
Question 4. What is Strait? Give example.
Answer: A strait is a narrow strip of water body joining two large water bodies, eg., Palk strait, Strait of Gibraltar, or Bering strait.
Question 5. Mention the four major parts of the ocean floor.
Answer:
The continental shelf
The continental slope
The deep sea plain
The ocean deeps are the four major parts of the ocean floor
Question 6.The salinity of ocean water changes in different parts of the earth. Why?
Answer: The salinity of ocean water is very high near the tropics and it is very low near the poles. In the equatorial region, the salinity is average due to high evaporation and precipitation.
Kseeb Class 8 Social Science Geography Chapter 4 Exercise Answers
Question 7. What are the factors that influence ocean currents?
Answer: Factors that influence ocean currents are the Rotation of the Earth, Temperature, Wind, Salinity, Shape of the landmasses, etc.
Question 8. How are the tides caused?
Answer: Tides occur due to, gravitational attraction by the moon, gravitational force by the sun, rotation of the earth, and, the centrifugal force of the earth.
Question 9. How are the tides useful to Human beings?
Answer:
Tides are directly and indirectly useful to mankind in the following ways.
It helps navigation.
Helps in the location of ports and harbors.
Tides help to keep the harbors clean.
They help with fishing.
They also help to generate energy in the form of tidal energy.
Question 10. The conservation of oceans is very important. Why?
Answer: Oceans help us in many ways and they are the habitat of millions of marine organisms. Considering the rate at which the oceans are being contaminated, they may not remain what they should be in the future.