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class VII

Key Concepts

types of heat, transfer of heat, measurement of heat, unit of heat, heat and its effects on air, heat and its effects on various materials, heat and state of matter

essential questions

1.Why do you think we needed to find a way to measure heat?
2. Why do you think there are two types of thermometers to measure temperature?
3. Have you ever wondered why mercury has been used to show the change in temperature in a thermometer?
4. How does transfer of heat happens between states of matter?
5. How do we get heat from the sun?
6. Why is our sense of touch not reliable for measuring heat?


  1. Define heat? How do we measure heat? What is the unit of heat?
  2. Name the various states of matter?


  1. What is thermal equilibrium?
  2. What do we mean by absolute temperature?
  3. What is boiling point of any substance?
  4. What is a thermometer? What principle does it work on?
  5. What is the co-relation between melting and freezing points?
  6. Is wood a good or bad conductor of heat? With what experiment can you show?
  7. What are conductors and insulators?
  8. Write down the difference between conduction convection and radiation.
  9. How does convection lead to sea and land breeze? Show with diagram.
  10. Explain the concept radiation with the example of thermos flask?
  11. Write down the differences between:

a) Melting point and Freezing point

b) Vaporization and Condensation

c) Vaporization and Sublimation

d) Sublimation and Solidification



  1. Why do we use liquids as thermometric substances and not any kind of solid? Give reasons
  2. Using the principle of radiation can you think of any everyday electrical appliance that is used by us?
  3. Can you tell how the concept of radiation is used in microwaves.
  4. Air is a bad conductor of heat? How do we use this quality of air in everyday life?


  1. Can we say any kind of change that takes place in states of matter is because of change in in heat? Explain with reasons.
  2. When a candle is lit the wax melts. Give reasons why? Explain using the change in states of matter.
  3. Why does ice melt when kept at room temperature?
  4. Give reasons on why thermal expansion happens in state of matter? Give examples
  5. How does radiation help in heating up the object? Explain with a diagram.