Hydrosphere Class 8 Extra Questions and Answers Notes
We have provided here Hydrosphere Class 8 Extra Questions and Answers Notes by our Experienced Teacher. This Extra Questions and Answers Notes consists of MCQ Questions and Answers; Very Short Type Questions and Answer & Short Type Questions and Answers.
Mcq
1.) What percentage of the Earth’s surface is covered by water?
a) 50%
b) 71%
c) 30%
d) 90%
Answer: b)
2.) Which ocean is located between North America and Europe?
a) Indian Ocean
b) Atlantic Ocean
c) Pacific Ocean
d) Arctic Ocean
Answer: b)
3.) Which of the following is not a major water body?
a) Gulf
b) Bay
c) Peninsula
d) Strait
Answer: c)
4.) What is the deepest part of the ocean, located in the Mariana Trench?
a) Challenger Deep
b) Abyssal Plain
c) Ocean Trench
d) Submarine Canyon
Answer: a)
5.) What is the average salinity of ocean water in parts per thousand (PPT)?
a) 10 PPT
b) 25 PPT
c) 35 PPT
d) 50 PPT
Answer: c)
6.) Which type of ocean current originates in polar regions and flows towards the equator?
a) Warm currents
b) Cold currents
c) Equatorial currents
d) Coastal currents
Answer: b)
7.) What causes spring tides?
a) Earth, Moon, and Sun in a straight line
b) Earth, Moon, and Sun at right angles
c) Earth, Moon, and Sun forming an equilateral triangle
d) Earth and Moon on opposite sides of the Sun
Answer: a)
8.) How often do neap tides occur in a lunar month?
a) Once
b) Twice
c) Three times
d) Four times
Answer: b)
9.) What is the main purpose of conserving oceans?
a) Maintaining water quality for drinking
b) Protecting marine biodiversity
c) Promoting tourism
d) Supporting agriculture
Answer: b)
10.) Which source of energy can be generated from ocean tides?
a) Solar energy
b) Wind energy
c) Tidal energy
- d) Geothermal energy
Answer: c)
One liners:
1.) What is the term for a deep and large expanse of water found between continents?
Answer: Ocean
2.) What is the narrow strip of water that joins two large water bodies called?
Answer: Strait
3.) What are the alternate rise and fall of sea or ocean levels called?
Answer: Tides
4.) What is the shallow area along the sea coast called?
Answer: Continental shelf
5.) What is the percentage of salts dissolved in sea or ocean water?
Answer: Salinity
6.) Which currents originate in the equatorial regions and flow towards sub-polar regions?
Answer: Warm currents
7.) What is the vast plain found at the bottom of the ocean floor?
Answer: Deep sea plain (Abyssal plain)
8.) What is the period of time between one high tide and the next high tide?
Answer: 12 hours and 26 minutes
9.) What is the term for the conservation of oceans and marine life?
Answer: Marine conservenerg
10.) What is the energy generated from the rise and fall of ocean tides called?
Answer: Tidal energy
Short questions :
1: Why is Earth often called the “blue planet”?
A: Earth is often called the “blue planet” because approximately 71% of its total surface, covering 361 million square kilometers, is covered by water, giving it a distinctly blue appearance when viewed from space.
2: What are the world’s largest oceans and can you name any countries that border these oceans?
A- The world’s largest oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean. Countries bordering these oceans include the United States, Canada, Russia, Japan, Australia, Brazil, South Africa, India and many others.
3: How do seas differ from oceans and can you give examples of seas?
A: Seas are smaller bodies of salt water that are partially surrounded by land and are usually extensions of oceans. Examples of seas are the Arabian Sea, the Caspian Sea and the Red Sea.
4: What separates a bay from the sea and can you give examples of bays?
A: A gulf is a part of an ocean or sea that extends over land and is smaller than a sea. Gulfs include the Gulf of Mannar, the Persian Gulf, and the Gulf of Mexico.
5: How do bays differ from bays and can you name any bays around the world?
A: Bays are small semicircular bodies of water that are partially surrounded by land, while gulfs are larger landward extensions of seas or oceans. Bays include Bay of Bengal, Bay of Biscay and Hudson Bay.
6: What is an isthmus and why is an isthmus important in geography?
A: An isthmus is a narrow strip of land that connects two larger land masses. Isthmuses are important because they can be used to build canals, such as the Suez Canal and the Panama Canal, which have considerable economic and navigational value.
7: What are the four main parts into which the sea floor is divided according to characteristics?
A: The sea floor is divided into four main parts according to their characteristics: continental shelf, continental shelf, abyssal plain and oceanic trenches.
8: How does ocean water temperature vary with latitude and depth?
A: Ocean water temperature varies with latitude, and equatorial regions have higher temperatures than polar regions. In addition, ocean water temperature generally decreases with increasing depth, as sunlight penetration is limited to the upper layers.
9: What factors affect the salinity of seawater and how does salinity vary in different regions of the ocean?
A: Salinity, or the concentration of salts in ocean water, is affected by factors such as evaporation, precipitation and freshwater flow from rivers. Salinity is highest near the equator and lower near the poles due to differences in temperature and precipitation.
10: How do ocean currents form and what are the two main types of temperature-based ocean currents?
A: Ocean currents are shaped by factors such as wind, temperature and shape of land masses. The two main types of ocean currents based on temperature are warm currents (which flow from the equator to the subpolar regions) and cold currents (which originate in the polar regions and move equatorward).
Long answer type:
1: What are the main bodies of water on Earth and why is our planet often called the “blue planet”?
A: The Earth is often called the “blue planet” because about 71% of its total surface, which is 361 million square kilometers, is covered by water. The largest bodies of water in the world are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean. These vast oceans are deep water areas that lie between the continents. They play an important role in regulating the Earth’s climate, supporting marine life and influencing weather patterns. The abundance of water on Earth is a unique feature that makes our planet habitable and supports various ecosystems.
2: Describe and give examples of the different categories of water bodies such as oceans, seas, bays, gulfs, straits and isthmuses.
A: Earth’s water bodies are in different forms:
-Oceans: Oceans are large bodies of water that separate continents, such as the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean.
– Seas: Seas are smaller than oceans and can be partially dry, such as the Arabian Sea, the Caspian Sea and the Red Sea.
– Persian Gulfs: Gulfs are depressions in the ocean or sea that extend on land, such as the Gulf of Mannar, the Persian Gulf and the Gulf of Mexico.
– Bays: Bays are semicircular bodies of water partially surrounded by land, such as the Bay of Bengal, Bay of Biscay and Bay of Fundy.
– Straits: Straits are narrow waterways that connect two larger bodies of water, such as the Palk Strait, the Strait of Gibraltar and the Bering Strait.
– Isthmuses: Isthmuses are narrow landmasses that connect two larger landmasses, such as the Suez Canal and the Panama Canal.
3: Based on these features, what are the four main parts of the sea floor and why is it important to know sea floor topography?
A: The seabed has different parts with unique properties:
-Continental Shelf: This shallow area extends along the coast and gradually increases in depth towards the continental shelf. It is crucial for fishing, navigation and mining.
– Continental Shelf: This steep area connects the continental shelf to the deep sea plateau and often contains submarine canyons.
– Abyssal Plain: This large flat area covers most of the sea floor and is home to seamounts and mountain ranges.
– Ocean depths: These are the deepest parts of the seabed, such as the Challenger Deep in the Mariana Trench region. Knowledge of seafloor topography is essential to understanding the importance of the ocean, its ecosystem and geological processes.
4: Explain the factors that affect the temperature and salinity of seawater and how they vary in different regions.
A- Seawater temperature and salinity vary due to several factors:
-Temperature: The temperature of ocean water varies according to latitude and depth. The water in the equatorial regions is warmer than in the polar regions. Sunlight penetrates through the surface layer, bringing warmer surface water with it.
– Salinity: Factors affecting salinity and seawater salinity such as evaporation and precipitation. Near the tropics, high evaporation leads to higher salinity, while at the poles, low evaporation and freshwater inflow lead to lower salinity.
Question 5: Describe the types of tides, their causes and significance, including spring tides and spring tides.
A: Tides are the regular rise and fall of sea or ocean level. They are caused by the gravitational pull of the Moon and the Sun on the Earth, as well as the rotation and centrifugal force of the Earth. Tides are divided into two main types:
-Spring tides: These occur during new and full moons when the earth, moon and sun are aligned. Spring tides cause the highest high tide and the lowest low tide, causing significant tidal fluctuations.
– Bad tides: Bad tides occur in the first and third quarter of the month, when the moon and the sun form a right angle to the Earth. Tides cause small changes in high and low tides. Tides are essential for navigation, locating harbors and coastal ecosystems.