Radiation: Heat That Travels Without Touch

Radiation is a mode of heat transfer that allows heat to travel without the need for any material medium. It is the process by which energy moves in the form of waves, making it different from conduction and convection.

Radiation helps us explain how heat from the Sun reaches the Earth and how we feel warmth from objects even without direct contact. In this article, we will learn what radiation definition is, and how heat gets absorbed and reflected.

Table of Contents

• What is Radiation?
• Real Examples of Radiation
• Absorption and Reflection of Heat

What is Radiation?

Heat is emitted by the bodies in the same way as the sun emits heat that reaches us. The mode of heat transfer in both the processes is termed as radiation. 

“The mode of transmitting heat that requires no medium is called radiation.”

This heat is transmitted in the form of electromagnetic waves.

All objects radiate heat in space. 

Real Examples of Radiation

Let’s look at some common examples to understand how radiation works in real life. For example, the Sun’s energy reaches us through radiation. We feel the heat of the bonfire as well as heater through radiation.

Radiation allows heat to travel through empty space without the need for any kind of medium. This is the reason why we can feel the warmth of the Sun even though it is very far away.

Similarly, when we stand near a bonfire or a heater, we feel warm without touching it because heat is transferred through radiation.

Absorption and Reflection of Heat

Moving ahead, let’s understand what happens when heat falls on objects.

When heat falls on an object, some amount of heat gets absorbed by it, thus increasing the temperature of the object. The amount of heat that any object can absorb depends upon its colour. 

Dark-coloured objects absorb more heat compared to light-coloured objects. There is also some amount of heat that is always reflected back. The remaining part of the heat that is absorbed is transmitted back into space. 

Here is an important fact to remember: the greater the absorption of heat, the higher the amount of heat transmitted by the body.

So far, in this article, we have understood that radiation is a mode of heat transfer that does not require any medium and occurs through electromagnetic waves. We also explored how heat is absorbed and reflected by different objects and their examples in daily life.