Welcome to Bodhiclasses, where learning is designed to be structured, concept-driven, and exam-ready. Below is a sample question paper based on Class 7 Science – Chapter 7: Heat Transfer in Nature, followed by a separate solution sheet.
Section A: Multiple Choice Questions (MCQs): Heat Transfer
(10 × 1 = 10 marks)
- Which of the following materials is a good conductor of heat?
(a) Plastic
(b) Wood
(c) Copper
(d) Air - Heat transfer in solids mainly takes place through:
(a) Convection
(b) Radiation
(c) Conduction
(d) Evaporation - Which process of heat transfer does not require any medium?
(a) Conduction
(b) Convection
(c) Radiation
(d) Insulation - Sea breeze blows during:
(a) Night
(b) Early morning
(c) Daytime
(d) Midnight - Woollen clothes keep us warm because they:
(a) Produce heat
(b) Trap air
(c) Reflect heat
(d) Absorb cold - Smoke from a burning fire rises upward because:
(a) It is heavy
(b) It is cold
(c) Hot air expands and becomes lighter
(d) Gravity pulls it upward - Which material allows maximum seepage of water?
(a) Clay
(b) Soil
(c) Sand
(d) Gravel - Which colour clothes are most suitable during summer?
(a) Black
(b) Dark blue
(c) White
(d) Brown - Underground layers that store water are called:
(a) Glaciers
(b) Rivers
(c) Aquifers
(d) Clouds - Ice stupas are mainly found in:
(a) Rajasthan
(b) Kerala
(c) Ladakh
(d) Assam
Section B: One-Mark Questions: Heat Transfer
(10 × 1 = 10 marks)
- Name the process of heat transfer in liquids and gases.
- Which gas trapped in woollen clothes helps keep us warm?
- What is infiltration?
- Name the process by which water vapour changes into clouds.
- Which breeze blows from land to sea?
- Name one poor conductor of heat.
- Which source provides energy for the water cycle?
- What form of heat transfer occurs from the Sun to the Earth?
- What is groundwater?
- Which type of bricks are used to keep houses cool in hot regions?
Section C: Two-Mark Questions: Heat Transfer
(10 × 2 = 20 marks)
- Why are cooking utensils generally made of metals?
- Why do metals feel colder than wood during winter?
- Explain why smoke detectors are placed near ceilings.
- Why does land heat up faster than water during the day?
- What is convection? Explain with one example.
- Why do we prefer two thin blankets over one thick blanket in winter?
- What is an aquifer? Write its importance.
- How does radiation differ from conduction?
- Why do coastal areas experience moderate climate?
- Explain why air is considered a poor conductor of heat.
Section D: Higher Order Thinking Skills (HOTS)
(5 × 3 = 15 marks)
- If Earth had no atmosphere, how would radiation from the Sun affect life on Earth? Explain.
- Why does excessive construction in cities lead to groundwater depletion?
- How do hollow bricks help in saving energy in buildings?
- Why are ice stupas considered a sustainable solution for water scarcity?
- How are conduction, convection, and radiation involved when water is heated in a pan?
SOLUTION SHEET: HEAT TRANSFER
Section A: MCQs – Heat Transfer
- (c) Copper
- (c) Conduction
- (c) Radiation
- (c) Daytime
- (b) Trap air
- (c) Hot air expands and becomes lighter
- (d) Gravel
- (c) White
- (c) Aquifers
- (c) Ladakh
Section B: One-Mark Answers
- Convection
- Air
- Infiltration is the process by which water seeps into the ground.
- Condensation
- Land breeze
- Wood (or plastic/glass)
- The Sun
- Radiation
- Water stored below the Earth’s surface is called groundwater.
- Hollow bricks
Section C: Two-Mark Answers
- Metals are good conductors of heat and allow food to cook faster.
- Metals conduct heat away from our body quickly, while wood does not.
- Smoke rises upward due to hot air, so detectors work best near ceilings.
- Land has lower heat capacity than water, so it heats faster.
- Convection is heat transfer by movement of particles, e.g., rising hot air.
- Air trapped between blankets acts as an insulator and reduces heat loss.
- An aquifer is an underground layer storing water; it supplies wells and borewells.
- Radiation needs no medium, while conduction needs direct contact.
- Large water bodies heat and cool slowly, preventing extreme temperatures.
- Air does not allow heat to pass easily and slows heat transfer.
Section D: HOTS Answers
- Without atmosphere, excessive radiation would make Earth extremely hot during the day and freezing at night, making life impossible.
- Concrete surfaces prevent infiltration, reducing groundwater recharge.
- Air trapped in hollow bricks acts as an insulator, reducing heat transfer and energy use.
- Ice stupas store winter water as ice and release it slowly in summer, solving seasonal water scarcity.
- Heat moves from flame to pan by conduction, circulates in water by convection, and spreads around by radiation.
