All things are made up of molecules. When things get heated, they absorb heat energy. With more energy, molecules are able to move faster, and when molecules move faster, the temperature rises.

What is Thermal Energy Transfer

• Thermal Energy is energy resulting from the motion of particles
• It is a form of kinetic energy and is transferred as heat
• Thermal Energy Transfer can occur by three methods:
• Conduction
• Convection
• Radiation

Thermal Energy Transfer Definitions & Examples

Conduction

• Conduction is the transfer of thermal energy through direct contact between particles of a substance, without moving the particles to a new location
• Usually occurs in solids
• When heat is supplied to one end, molecules at that end start to move more quickly
• In the process, they bump into their neighbors, transferring the kinetic energy

Convection

Convection is the transfer of thermal energy through the movement of particles from one location to another. It usually occurs in fluids (liquids and gasses).

Example: boiling water

• Water at the bottom of the pan is heated first.
• Heated water expands and density decreases.
• Heated water begins to rise.
• Cooler water with higher density from the sides of the pan rushes down to take its place.
• The cooler water gets heated and the cycle repeats.

We call these Convection Currents.

Radiation

Radiation is the emission of energy as waves, particles, or rays. Radiation does not require a medium to transfer energy. Radiant energy is either reflected or absorbed by matter. The energy that is absorbed increases the kinetic energy of the object, thus increasing its temperature.

Example: frying pan on a stovetop

• Energy is radiated from the heat source and absorbed by the lower surface of the pan.

Example: the sun

• The sun radiates energy in the form of solar radiation.
• When this energy reaches Earth, it is absorbed by matter (air, water, land).
• Absorbed radiant energy increases the kinetic energy of the matter, raising its temperature.

Factors Affecting Radiation

ALBEDO

• Albedo is the percentage of incoming solar radiation that a surface reflects.
• The albedo of Earth is about 30%.
• Light-colored, shiny objects reflect more solar radiation and have a high albedo (e.g., ice, snow, sand).
• Darker, dull objects absorb more solar radiation and have a low albedo (e.g., forests, soils).

Surface Area

• The larger the surface area, the higher the rate of transfer
• Thermal Energy Transfer in the Atmosphere
• Things to Know:
  • Atmospheric Pressure > the pressure exerted by the mass of air above any point on Earth’s surface
  • Warm air is less dense than cold air
  • Warmer regions generally have less atmospheric pressure than colder regions
  • Wind > the movement of air from areas of high pressure to areas of low pressure
  • The rising and sinking masses of air in convection currents cause changes in atmospheric pressure … causing wind

Thermal Energy Transfer in the Atmosphere

Things to Know:

• Atmospheric Pressure: The pressure exerted by the mass of air above any point on Earth’s surface.
• Warm air is less dense than cold air.
• Warmer regions generally have less atmospheric pressure than colder regions.
• Wind: The movement of air from areas of high pressure to areas of low pressure.
• The rising and sinking masses of air in convection currents cause changes in atmospheric pressure, causing wind.

Wind Patterns and Coriolis Effect

• Wind moves from WEST to EAST.
• It is closer to the equator in colder months and closer to the Poles in warmer months.

Thermal Energy Transfer in the Hydrosphere

The effect of water on the transfer of heat is significant. Earth’s climate is affected by phase changes in the water cycle.

Water Cycle

• Water molecules undergo changes of state (e.g., solid to liquid).
• When these changes occur, thermal energy is either released or absorbed.
  • Released from liquid to solid.
  • Absorbed from liquid to gas.
• Temperature remains the same between phase changes.
• Through changes of state is how thermal energy is transferred through the biosphere.

Ocean Currents

• Ocean currents are main pathways to transfer thermal energy from warmer regions to cooler regions.
• Global winds push the water, driving the surface currents of the ocean.
• The pattern of ocean currents is modified by the Coriolis Effect:
  • Currents in the North veer to the right.
  • Currents in the South veer to the left.
• Thermal energy is also transferred vertically via convection currents (same principles as with air).

Thermal Energy Transfer Examples in Everyday Life

Thermal energy transfer examples are evident in everyday life. For instance, when you place a metal spoon in a hot cup of coffee, the handle soon becomes warm due to conduction. Another common example is the convection currents observed when boiling water on a stove. Additionally, the warmth you feel from the sun is a result of radiation.

These examples help us understand the question: what is thermal energy transfer? More specifically, how it impacts our daily activities. By studying these thermal energy transfer examples, we gain a deeper appreciation for the various mechanisms through which heat energy is distributed in our environment.

William Anderson (Schoolworkhelper Editorial Team)

William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0

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