HEAT TRANSFER PART 1

HEAT TRANSFER

By Elias Chinyanta - AAL2025

Multiple Choice

WHAT IS HEAT TRANSFER?

• Heat transfer is the movement of thermal energy between physical systems.
• Heat transfer is the increase of pressure in a gas.
• Heat transfer refers to the generation of electricity.
• Heat transfer is the process of cooling down objects.

1. Conduction:
This is the transfer of heat through solids.
- Heat is transferred from a region of higher thermal energy to a region of lower thermal energy by vibration of particles.
Conduction can be demonstrated using the following experiment:


Observation:

Types of heat transfer:

HEAT TRANSFER - Movement of thermal energy from a region of high thermal energy to a region of lower thermal energy.

​Conclusion:
Heat energy travels in solids through conduction from hotter region to the colder region.

Multiple Choice

DEFINE CONDUCTION OF HEAT

• Conduction of heat is the transfer of heat via electromagnetic waves.
• Conduction of heat is the transfer of heat through direct contact between materials.
• Conduction of heat occurs only in gases.
• Conduction of heat is the movement of heat through fluids.

2. Convection: This is the transfer of heat through liquids and gases.

- In convection, heat is carried by the particles from the hot region to the cold region.

- When a liquid is heated, molecules move further apart.

- The density decreases when a fluid is heated.

- The heated part rises and unheated dense part goes down and this creates a current that

carry heat. Examples of convection in nature are sea (onshore) and land (offshore)

breezes.

Types of heat transfer:

HEAT TRANSFER - Movement of thermal energy from a region of high thermal energy to a region of lower thermal energy.

Multiple Choice

DEFINE CONVECTION OF HEAT

• Convection of heat occurs only in gases and not in liquids.
• Convection of heat is the transfer of heat through solid materials.
• Convection of heat is the transfer of heat through the movement of fluids.
• Convection of heat is the process of heat being absorbed by a surface.

3. Radiation: movement of thermal energy through electromagnetic waves, like infrared or visible light, without the need for a medium (like air or water) to carry the heat.. It can also take place in a vacuum (empty space).

- The heat reaching your hands when you hold them near a fire reaches them by radiation.

- Heat from the sun reaches us also by radiation.

Types of heat transfer:

HEAT TRANSFER - Movement of thermal energy from a region of high thermal energy to a region of lower thermal energy.

Multiple Choice

DEFINE RADIATION OF HEAT

• Radiation of heat is the conduction of energy through solids.
• Radiation of heat is the transfer of thermal energy through electromagnetic waves.
• Radiation of heat is the movement of air particles.
• Radiation of heat is the process of cooling by evaporation.