📘 Class 7 Heat Chapter: Key Concepts Every Student Must Know 🔥 (CBSE 2025)

 

👋 Still confused about heat transfer, conduction, and thermometers?

Here’s your ultimate guide to the Class 7 NCERT Science Chapter – Heat. Perfect for quick revision, CBSE exam prep, or classroom reference. ✅

🟠 Chapter: Heat – Class 7 Science

Understanding heat and how it moves is the foundation of thermal science. This chapter helps you master temperature, thermometers, and everyday heat-related phenomena.

🔥 1. What is Heat?

• Heat is a form of energy that makes things hot or cold.
• It always flows from a hotter object to a colder object.

🌡️ 2. Hot and Cold

While our skin can sense hot or cold, it’s not accurate.

✔️ Thermometers are used to measure temperature precisely.

🧪 3. What is Temperature?

• Temperature tells us how hot or cold something is.
• Measured in:
  • Degrees Celsius (°C)
  • Degrees Fahrenheit (°F)

🎯 Normal body temperature:
37°C or 98.6°F

🧴 4. Thermometers: Types & Uses

Thermometer Type	Use	Temperature Range
Clinical Thermometer	Measures human body temperature	35°C to 42°C
Laboratory Thermometer	Used in labs & experiments	–10°C to 110°C

✅ Clinical thermometer has a kink to prevent mercury from falling back.
❌ Lab thermometers don’t have this and aren’t used on humans.

🛣️ 5. How Does Heat Transfer?

Heat moves in three main ways:

Mode of Transfer	Description	Real-life Example
Conduction	Heat transfer in solids by contact	Cooking in a metal pan
Convection	Heat transfer in liquids and gases	Boiling water, sea breeze
Radiation	Heat transfer without a medium	Sun heating the Earth

🔩 6. Conductors and Insulators

Type	What It Does	Examples
Conductors	Allow heat to pass through easily	Metals (iron, copper)
Insulators	Do not allow heat to pass easily	Wood, plastic, wool, air

🌬️ 7. Sea Breeze & Land Breeze Explained

☀️ Day (Sea Breeze):

Land heats up → Hot air rises → Cool air from sea replaces it.

🌙 Night (Land Breeze):

Sea is warmer → Hot air over sea rises → Cool air from land moves in.

✅ This cycle creates coastal breezes daily.

🧥 8. Clothes & Seasonal Heat

• Winter: Woolen clothes trap air → keep us warm.
• Summer: Light-colored cotton clothes → reflect heat + absorb sweat.

🧠 Smart dressing = smart heat management!

 

What is Heat Transfer?

Heat transfer is the movement of thermal energy from a hotter body to a cooler one. It occurs through:

✅ Conduction
✅ Convection
✅ Radiation

📘 Modes of Heat Transfer – Overview

🧊 1. Conduction – Heat Through Solids

Definition:
Transfer of heat within solids by direct contact.

Best in: Metals
Bad in: Wood, plastic, rubber (called insulators)

Example:
When you heat one end of an iron rod, the other end becomes hot.

📊 Conductors vs Insulators

🌊 2. Convection – Heat Through Liquids & Gases

Definition:
Transfer of heat in fluids (liquids and gases) through movement of particles.

Example:
Boiling water or warm air rising up

Natural Examples:

• Sea breeze and land breeze

• Geysers and hot springs

☀️ 3. Radiation – Heat Without Medium

Definition:
Heat transfer that doesn’t need any medium, carried by infrared rays.

Example:
Sunlight reaching Earth.
Feeling warm from a heater even from a distance.

🔁 Summary : Heat Transfer Comparison

🧠 Quick Revision Tricks

• Conduction = Contact (solid to solid)

• Convection = Currents (in liquids/gases)

• Radiation = Rays (through vacuum)

📝 Practice Questions

1. Why does a metal pan handle feel hot?
   👉 Due to conduction of heat through metal.

2. How does heat reach you from a bonfire?
   👉 Through radiation.

3. Why does water boil from the bottom up?
   👉 Because of convection currents.

📣 Final Tip for CBSE Students

Mastering the three modes of heat transfer helps not only in exams but also in understanding daily life examples like cooking, weather, and climate! ✅

📝 Key Terms Recap

• Heat – Energy that moves from hot to cold.
• Temperature – Measures how hot/cold something is.
• Conduction – Transfer in solids.
• Convection – Transfer in liquids/gases.
• Radiation – Transfer without contact.
• Conductor – Allows heat.
• Insulator – Blocks heat.

💡 Quick Science Tip

• Mercury is used in thermometers because it expands uniformly and is visible.
• Never use a clinical thermometer for lab experiments — it’s not designed for that!

📥 FREE Resources for You!

 

• 📘 NCERT Class 7 Science eBook – Official Site
• 🏠 Visit CuriousCornor.com for More Content