Oceans and Continents – Case-based Questions with Answers
Class 6
CBSE Class 6 Social Science — Chapter 2: Oceans and Continents
CBSE Board Examinations: Case-Based Questions, Map skills, Short & Long answers, Internal assessment.
Content Bank — Chapter 2 (Topic-wise)
Topics: Major Oceans; Continents & key features; Oceanic features (currents, trenches); Islands, peninsulas & isthmuses; Human uses — trade & resources; Map skills & coordinates.
Scenario 1: A teacher shows pictures of the Pacific and the Arctic Oceans. Students notice differences in ice cover and marine life.
Q1.1 What key differences would you highlight between these two oceans?
A1.1: Pacific is largest and deep with warm to temperate waters, rich island biodiversity; Arctic is smallest, shallow, with seasonal ice cover and specialized cold-adapted species.
Q1.2 How do these differences affect human activities?
A1.2: Pacific supports major shipping, fisheries, and tourism; Arctic has limited shipping (seasonal), scientific research, and emerging resource exploration constrained by ice and fragile ecosystems.
Scenario 2: A coastal village relies on fishing but catches decline despite using the same fishing methods.
Q2.1 Suggest possible ocean-related reasons for the decline.
A2.1: Overfishing reducing stocks, changes in ocean currents or temperature affecting fish migration, pollution or loss of breeding habitats (reefs, estuaries).
Q2.2 Recommend two practical steps to help the village recover fish stocks.
A2.2: Implement sustainable fishing practices (limits, seasonal bans), protect nursery habitats and promote alternative livelihoods like eco-tourism.
Scenario 3: A map shows the Tropic of Cancer passing through India. Students discuss its significance.
Q3.1 What is the Tropic of Cancer and why is it important for India?
A3.1: Tropic of Cancer (~23.5°N) marks northernmost latitude of direct overhead sun; influences climate zones and intensity of seasons in parts of India.
Q3.2 How might this help in answering an exam map question?
A3.2: Marking Tropic of Cancer helps show climatic zones and locate states it passes through—useful for map labelling and explaining climate-related questions.
Scenario 4: Students compare maps: one large-scale town map and one small-scale world map.
Q4.1 Which map would be better to show the location of a local harbour and why?
A4.1: Large-scale town map — it shows local details like harbour layout, piers and access roads necessary for local planning.
Q4.2 Which map is better to show ocean positions relative to continents?
A4.2: Small-scale world map — covers entire globe and shows relative positions of oceans and continents despite less detail.
Scenario 5: A student notices warm water near a coastline and colder water further away and asks the teacher why.
Q5.1 Explain what might cause this pattern.
A5.1: Coastal warming can be due to warm ocean currents or shallow seas heating faster; cold water offshore could be from cold currents or upwelling bringing deep water to the surface.
Q5.2 How does this affect local fishing?
A5.2: Upwelling areas with cold nutrient-rich water often support richer fisheries due to high plankton production.
Scenario 6: A country plans a port but the proposed site is on a narrow peninsula with strong coastal currents.
Q6.1 What coastal and ocean factors should planners assess?
A6.1: Assess current strength for navigation safety, sedimentation patterns, tidal range, depth for ships, vulnerability to storms and erosion, and environmental impacts on marine habitats.
Q6.2 Suggest one mitigation measure for strong currents.
A6.2: Construct breakwaters or design harbour orientation to reduce wave energy; use pilotage services and dredging plans for safe navigation.
Scenario 7: A student reads that the Mid-Atlantic Ridge is an underwater mountain range; the class debates its origin.
Q7.1 Explain how the Mid-Atlantic Ridge forms.
A7.1: It forms at a divergent plate boundary where tectonic plates move apart, allowing magma to rise and create new oceanic crust (sea-floor spreading).
Q7.2 Why is this important for understanding continents and oceans?
A7.2: It provides evidence for plate tectonics and explains how ocean basins expand, influencing the distribution of continents over time.
Scenario 8: A school project compares the Sahara Desert and the Amazon Rainforest.
Q8.1 Give two contrasting physical features of these regions.
A8.1: Sahara — arid, sparse vegetation, extreme temperatures; Amazon — humid, dense rainforest, high biodiversity and heavy rainfall.
Q8.2 How do these features influence human settlement?
A8.2: Sahara limits agriculture and dense settlement; Amazon supports indigenous communities but dense forest can limit large-scale urban development.
Scenario 9: Students learn about exclusive economic zones (EEZs) and wonder why countries claim them.
Q9.1 What is an EEZ and why is it important?
A9.1: EEZ is a sea zone up to 200 nautical miles where a country has rights to exploit marine resources (fish, oil). It secures economic benefits and resource control.
Q9.2 What kinds of disputes can EEZs cause?
A9.2: Overlapping claims, especially in narrow seas, can cause disputes over fishing rights, oil exploration and maritime boundaries.
Scenario 10: A student notices coral bleaching images and asks what causes it.
Q10.1 Explain coral bleaching and its main causes.
A10.1: Coral bleaching occurs when corals expel symbiotic algae (zooxanthellae) due to stress (mainly increased sea temperatures, pollution, acidification), losing colour and vital energy source.
Q10.2 Suggest one conservation step to protect coral reefs.
A10.2: Reduce local pollution, regulate coastal development, establish marine protected areas and limit greenhouse gas emissions to control warming.
Scenario 11: A class studies why Europe developed dense trade networks historically.
Q11.1 Explain two geographic reasons that helped Europe's historical trade development.
A11.1: Extensive indented coastline and navigable rivers facilitated ports and inland transport; moderate climate supported agriculture and population growth aiding markets.
Q11.2 How can this be linked to modern economic geography?
A11.2: Historical port cities became modern economic hubs; trade networks evolved into global maritime routes influencing present-day trade patterns.
Scenario 12: Students plan a poster showing major ocean currents and their climate effects.
Q12.1 Name two major currents and their effects on climate.
A12.1: Gulf Stream (warm) warms northwest Europe; California Current (cold) cools California coast and reduces rainfall.
Q12.2 How does illustrating currents help understand weather patterns?
A12.2: Visuals show heat transport paths, helping explain temperature differences, rainfall patterns and regional climates influenced by currents.
Scenario 13: A student finds that some islands are disappearing and asks why.
Q13.1 What are the likely causes of island disappearance?
A13.1: Sea-level rise due to climate change, coastal erosion, subsidence and human activities (e.g., sand mining) can cause islands to shrink or submerge.
Q13.2 What actions can island nations take?
A13.2: Coastal protection (mangrove restoration, sea walls), reduce emissions globally, and plan for evacuation/relocation strategies where necessary.
Scenario 14: A geography quiz asks to locate Australia and explain why its flora and fauna are unique.
Q14.1 Why are Australia's plants and animals unique?
A14.1: Long geographic isolation led to evolution of endemic species; arid interior and varied habitats produced unique adaptations (marsupials, eucalyptus forests).
Q14.2 How would you show this on a map answer?
A14.2: Label Australia, indicate major biomes and note unique species examples (kangaroo, koala) with brief notes on isolation and adaptation.
Scenario 15: During a field trip, students see different beach types—rocky and sandy—and discuss reasons.
Q15.1 What factors determine beach type?
A15.1: Wave energy, rock supply, coastal geology and sediment transport determine whether beaches are rocky (high-energy coasts) or sandy (gentler waves, abundant sediment).
Q15.2 How does beach type affect human use?
A15.2: Sandy beaches are tourist-friendly and good for recreation; rocky shores may support fisheries and are less suitable for large-scale tourism.
Scenario 16: A student notices maps showing Europe and Asia sometimes as separate continents and asks why.
Q16.1 Explain why Europe and Asia are often treated as separate continents despite being one landmass.
A16.1: Historical, cultural and conventional reasons (Ural Mountains as a dividing line) lead to separate continental identities even though they form a single Eurasian landmass.
Q16.2 How can this be used in a short exam answer?
A16.2: Mention physical boundary (Urals) and cultural-historical distinctions; give examples of differing climates and cultures to support separation.
Scenario 17: A coastal city plans to expand its port but environmentalists warn about mangrove removal.
Q17.1 Why are mangroves important to coastal ecosystems?
A17.1: Mangroves protect coasts from erosion and storms, act as nurseries for fish, filter pollutants and store carbon—vital for both ecology and livelihoods.
Q17.2 Suggest a balanced approach for port expansion.
A17.2: Conduct environmental impact assessment, limit clearing of mangroves, create compensatory planting, use sustainable engineering to minimise damage and involve local communities.
Scenario 18: Students compare ocean temperatures and wonder how they affect weather and human life.
Q18.1 How do ocean temperatures influence coastal weather?
A18.1: Warm oceans increase evaporation and humidity, leading to higher rainfall and milder winters; cold currents cool coastal areas reducing rainfall and moderating temperatures.
Q18.2 Give one example linking ocean temperature to a local climate.
A18.2: The Gulf Stream warms Western Europe, giving milder winters than other regions at similar latitudes.
Scenario 19: A student reads about the Panama Canal and asks why it was built and how it changed trade.
Q19.1 Why was the Panama Canal built and how did it affect global shipping?
A19.1: Built to provide a shortcut between Atlantic and Pacific, reducing voyage time and costs; it transformed shipping routes, fostering faster global trade and strategic naval movement.
Q19.2 Mention one environmental concern linked to canals.
A19.2: Habitat alteration, saltwater intrusion and species transfer between oceans; require careful management to minimise ecological impact.
Scenario 20: For an exam, students must explain why learning about continents and oceans matters.
Q20.1 Provide three concise reasons linking this knowledge to daily life and global issues.
A20.1: (1) Helps understand weather and climate impacts on agriculture and safety; (2) Informs about trade, resources and economic links (ports, fisheries); (3) Raises awareness of environmental challenges like pollution and sea-level rise, guiding sustainable choices.
Note: These Case-Based Questions and Answers are prepared strictly as per the NCERT syllabus and are ideal for CBSE Class 6 revision, classroom discussion and exam practice.