radiate
Definition
Radiate means to emit energy in the form of waves or particles. The waves or particles can be of any type, including electromagnetic waves, sound waves, or heat waves.
For example, the sun radiates electromagnetic waves. The electromagnetic waves from the sun travel through space and reach Earth.
Another example of something that radiates is a fire. The fire radiates heat waves. The heat waves from the fire travel through the air and warm our bodies.
Radiation can be used to heat objects, to cook food, and to transmit information. It can also be harmful to our health.
How can the word be used?
The explosion radiated heat and light in all directions.
Different forms of the word
Verb:
- to emit rays of light, heat, or other energy.
- to spread out from a central point in all directions.
- to give off a strong or pleasant feeling.
Adjective:
- radiating.
- of or relating to radiation.
Etymology
The word "radiate" comes from the Latin word "radius", which means "ray".
The first recorded use of the word "radiate" in English was in the 14th century.
Question
What can radiation be used to do?
AQA Science Exam Question and Answer
Question:
Explain the concept of radiate in the context of heat transfer and provide an example of a real-world scenario where radiative heat transfer is significant.
Answer:
In heat transfer, "radiate" refers to the process by which heat is transferred through electromagnetic waves, specifically in the form of infrared radiation. This type of heat transfer does not require a medium, unlike conduction or convection, as it can occur in a vacuum. Radiative heat transfer involves the emission, absorption, and transmission of energy through electromagnetic radiation.
An example of radiative heat transfer is the warmth felt from the Sun on a sunny day. The Sun emits a vast amount of energy as electromagnetic radiation, including visible light and infrared radiation. When sunlight reaches the Earth, it warms surfaces and objects by radiative heat transfer. The heat energy from the Sun is absorbed by these surfaces, causing them to heat up. Later, these surfaces re-emit some of this absorbed energy as infrared radiation, which contributes to the warmth felt in the surroundings.
Radiative heat transfer is crucial not only in natural settings like the Sun's influence on Earth's climate but also in technology. For instance, thermal insulation materials used in spacecraft need to minimise radiative heat transfer to maintain stable temperatures in the vacuum of space.