Heat Class 7 (VII) Science, NCERT Book

1. Heat
Chapter 4

2. Introduction
• Heat is a form of energy which produces
sensation of warmth and flows when there is
a temperature difference between two
bodies.

3. Types of Thermometer
Clinical Thermometer
Laboratory Thermometer
Digital Thermometer

4. Clinical Thermometer
A clinical thermometer is a
temperature measuring
device used to measure
only the human body
temperature. The range of
a clinical thermometer is
35∘C to 42∘C.

5. Laboratory Thermometer
Laboratory thermometers are
designed to measure the
temperatures of objects
around us and not for
measuring human body
temperature. The range of a
laboratory thermometer is -
10°C to 110°C.

6. Digital Thermometer
Digital thermometers are
designed to measure the
temperatures of objects and
for measuring human body
temperature. Digital
thermometers contain a small
computing mechanism and a
resistor

7. Modes of Heat Transfer
Conduction
Convection
Radiation

8. Conduction
The process of heat transfer from hotter part of a material to its colder part
or from a hot material to a cold material in contact with it, without the
movement of material as a whole, is known as conduction. In all the solids,
heat is transferred by the process of conduction.
Conduction Conduction
Radiation
Convection

9. Convection
The process of heat transfer by the bulk movement of molecules within
fluids such as gases and liquids.
Conduction Conduction
Radiation
Convection

10. Radiation
The emission and the spread of energy in the form of waves, rays or
particles is called Radiation.
Conduction Conduction
Radiation
Convection