Class 7 Science Chapter 7 Heat Transfer in Nature Notes | Curiosity 2026-27 | Amresh Academy

 

 

🌟 Class 7 Science Curiosity – Chapter 7 Notes

🌡️ Heat Transfer in Nature | Amresh Academy

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📘 Introduction

Heat plays an important role in nature 🌍

👉 It transfers from hotter objects to colder objects

There are three main modes of heat transfer:

• Conduction
• Convection
• Radiation

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🔥 1. Conduction of Heat

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📌 Definition:

👉 Heat transfer from hot to cold without movement of particles

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⚙️ Key Points:

• Occurs mainly in solids
• Particles vibrate but do not move

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⚡ Conductors vs Insulators:

✔️ Good Conductors:

• Metals (steel, aluminium)
• Used in cooking utensils 🍳

❌ Poor Conductors (Insulators):

• Wood, glass, clay, air
• Used to keep things hot/cold ☕

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🧪 Example:

👉 Heat travels through a metal strip → wax melts → pins fall

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🌬️ 2. Convection

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📌 Definition:

👉 Heat transfer in liquids & gases by movement of particles

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🔄 Process:

• Hot fluid rises ⬆️
• Cold fluid sinks ⬇️

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🌫️ Examples:

• Smoke rising
• Water heating in a beaker

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🌊 Land and Sea Breeze:

🌞 Day (Sea Breeze):

• Land heats faster
• Warm air rises
• Cool sea air moves toward land

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🌙 Night (Land Breeze):

• Land cools faster
• Warm sea air rises
• Cool land air moves toward sea

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☀️ 3. Radiation

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📌 Definition:

👉 Heat transfer without any medium

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🔥 Examples:

• Sun’s heat reaching Earth ☀️
• Feeling heat from fire

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👕 Key Concept:

• Light-colored clothes → reflect heat (cool in summer)
• Dark-colored clothes → absorb heat (warm in winter)

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💧 4. Water Cycle

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📌 Definition:

👉 Continuous movement of water in nature

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🔄 Stages:

• ☀️ Evaporation → Water → Vapour
• 🌿 Transpiration → Plants release water
• ☁️ Condensation → Clouds form
• 🌧️ Precipitation → Rain/snow/hail
• 💧 Infiltration → Water enters ground

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🌍 Importance:

• Maintains water balance
• Refills rivers, lakes, oceans

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🌊 5. Groundwater and Aquifers

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💧 Groundwater:

👉 Water stored underground

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🪨 Aquifers:

👉 Rock layers that store water

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⚠️ Problem:

• Overuse → water depletion

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✅ Solution:

• Rainwater harvesting 🌧️
• Recharge pits

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🏠 6. Applications of Heat Transfer

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🍳 Cooking:

• Metals used (good conductors)

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🧥 Clothing:

• Wool traps air → keeps warm
• Light colors → cool in summer

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🏡 Houses:

• Hollow bricks trap air
  👉 Maintain temperature

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❄️ Water Conservation:

• Ice stupas (Ladakh) store water

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📌 Final Summary

👉 Heat transfers in three ways:

• Conduction 🔥
• Convection 🌬️
• Radiation ☀️

👉 Water cycle and heat are connected 🌍

👉 Understanding heat helps in:

• Daily life
• Environment
• Technology

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✨ Perfect for revision + exams + concept clarity 🚀

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