Class 8 Social Science Geography Chapter 5 The oceans and Seas

Class 8 Social Science Geography Chapter 5 The oceans and Seas Question Answer to each chapter is provided in the list so that you can easily browse throughout different chapter SEBA Class 8 Social Science Geography Chapter 5 The oceans and Seas Notes Pdf Download and select needs one.

Class 8 Social Science Geography Chapter 5 The oceans and Seas

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Also, you can read SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given SEBA Class 8 Social Science Geography Chapter 5 The oceans and Seas Solutions for All Subject, You can practice these here.

The oceans and Seas

Chapter – 5

Write answers.

(a) What are of ocean current? The causes.

Ans: Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind (Coriolis Effect), and water density. Ocean water moves in two directions: horizontally and vertically. Horizontal movements are referred to as currents, while vertical changes are called upwellings or downwellings.

Causes: 

(i) The wind, the Earth’s rotation, the shape of the coastline, and the presence of land masses.

(b) What do you mean by warm water current?

Ans: Warm ocean currents originate near the equator and move towards the poles or higher latitudes while cold currents originate near the poles or higher latitudes and move towards the tropics or lower latitudes. The current’s direction and speed depend on the shoreline and the ocean floor.

(c) What are the types of sea lives? On what basis are they classified?

Ans: Marine life encompasses a vast range of organisms that live in the ocean, and they can be classified based on various criteria. 

Here are some of the main types of sea life and the bases for their classification:

Types of Sea Life:

(i) Plankton:

(a) Phytoplankton: These are microscopic plants that perform photosynthesis. They are the primary producers in the ocean.

(ii) Nekton:

These are actively swimming organisms, such as fish, squids, and marine mammals, that can move independently of ocean currents.

Classification are: 

(i) Habitat:

(a) Pelagic: Organisms that live in the open water column (e.g., plankton, nekton).

(ii) Mobility:

(a) Planktonic: Drifting organisms that are carried by ocean currents (e.g., phytoplankton, zooplankton).

(d) Which are the suitable places for developing fishing grounds near the oceans?

Ans: The major fishing grounds on earth comprise the seas north of Japan where the warm Kuroshio Current meets the cold Kamchatka Current; the Grand Banks off Newfoundland where the North Atlantic Drift encounters the cold Labrador Current; and the sea around Iceland where the North Atlantic Drift meets the East Greenland.

2. Give reasons.

(a) The neap tide is not stronger than spring tide.

Ans: Neap tides are weaker than spring tides because they occur when the gravitational forces of the Moon and the Sun are perpendicular to each other relative to the Earth. This happens during the first and third quarters of the lunar month. The gravitational pull of the Sun partially cancels out the gravitational pull of the Moon, resulting in lower high tides and higher low tides. In contrast, spring tides occur when the Sun and the Moon are aligned (during the full moon and new moon), and their gravitational forces combine to produce the highest high tides and the lowest low tides.

(b) Now sea fishes are available everywhere for purchase.

Ans: Sea fishes are now available everywhere for purchase due to advancements in transportation, refrigeration, and global trade networks. Modern fishing techniques and aquaculture have increased fish production, while efficient cold storage and shipping methods allow fish to be transported over long distances without spoiling. Additionally, globalisation has facilitated international trade, making it easier to distribute seafood to markets around the world.

(c) Japan has experienced frequent tsunamis.

Ans: Japan is located at the convergence of multiple tectonic plates, making it one of the most seismically active regions in the world. The interactions between these plates result in frequent earthquakes, some of which are powerful enough to generate tsunamis.

(d) Ship transportation is the best system for international trade.

Ans: Ship transportation is considered the best system for international trade for several reasons:

(i) Cost Efficiency: Shipping is the most cost-effective method for transporting large volumes of goods over long distances.

(ii) Capacity: Ships can carry vast quantities of cargo, including heavy and bulky items that would be impractical to transport by air or land.

(e) The tidal power of the sun is less though it is bigger in size.

Ans: The tidal power of the Sun is less than that of the Moon because tidal forces depend not only on the mass of the celestial body but also on its distance from the Earth. The gravitational force that generates tides is inversely proportional to the cube of the distance between the two bodies. Although the Sun is much larger than the Moon, it is also much farther away. The Moon, being closer to the Earth, exerts a stronger tidal force despite its smaller size, making the lunar tides more significant than the solar tides.

3. (i) Choose the correct one.

(a) Polar region.

(b) Equatorial region.

(c) None.

Ans: (b) Equatorial region.

(ii) The rising and falling of ocean water twice daily is known as. 

(a) ocean current.

(b) Tide.

(c) wave.

Ans: (b) Tide.

(iii) Tsunami means.

(a) Earthquake.

(b) Waves.

(c) Pons.

Ans: (b) Waves.

(iv) The creatures of the ocean which can swim are-

(a) Nekton.

(b) Benthos.

(c) plankton.

Ans: (a) Nekton.

4. Match the following left side items with the right side-

Ans: