Difference Between Conduction, Convection and Radiation

Conduction, Convection, and Radiation: There are various terminologies we use in science that directly convey the properties of an element or object, for example, conduction, convection, and radiation. Let us understand them one by one and see how they differ from each other.

Jul 9, 2024, 16:12 IST

Check here Difference Between Conduction, Convection and Radiation

Difference Between Convection, Conduction, and Radiation: The process of transferring thermal energy from one system to another in the form of heat is called heat transfer. There are three types of processes through which it occurs: convection, conduction, and radiation. Let us see the difference between these three and understand them with examples.

Best Books for 6–8 Years: Check Summary, and Unique Features

Difference Between Conduction, Convection, and Radiation

Let us check the major differences between these three terms and understand them with examples.

Feature	Conduction	Convection	Radiation
Definition	Transfer of heat through a material without the movement of the material itself.	Transfer of heat by the physical movement of a fluid (liquid or gas).	Transfer of heat through electromagnetic waves without needing a medium.
Mechanism	Heat moves from molecule to molecule through direct contact.	Heat is carried by moving fluid particles from one place to another.	Heat is emitted as infrared radiation and travels through space.
Medium	Solids (primarily), but can occur in liquids and gases.	Fluids (liquids and gases).	Can occur in a vacuum (no medium needed).
Example	Heat traveling along a metal rod from a hot end to a cold end.	Boiling water where hot water rises and cold water sinks.	Heat from the Sun warming the Earth.
Speed of Heat Transfer	Generally slow.	Faster than conduction.	Fastest among the three methods.
Dependency	Depends on material properties like thermal conductivity.	Depends on fluid properties and temperature differences.	Depends on the surface temperature and nature of the material.
Temperature Gradient	Requires a temperature gradient within the material.	Requires a temperature gradient and fluid motion.	Can occur without a temperature gradient in the medium.

Read:

Detailed Explanation

Conduction:

How it works: Heat is transferred through direct molecular collisions. Molecules in the hotter part of the material vibrate more and transfer some of their energy to neighbouring cooler molecules.
Materials: Good conductors include metals like copper and aluminium. Insulators include wood and rubber.

Convection:

How it works: Heat transfer occurs through the movement of fluid. Warmer, less dense fluid rises, while cooler, denser fluid sinks, creating a circulation pattern.
Types: Natural convection (driven by buoyancy forces due to density differences) and forced convection (driven by external means like a pump or fan).

Radiation:

How it works: Heat is transferred through electromagnetic waves. All objects emit and absorb radiant energy. The amount of radiation emitted increases with the temperature of the object.
No medium needed: Unlike conduction and convection, radiation does not require a medium to transfer heat. This is why we can feel the heat from the Sun even though space is a vacuum.