- Conduction
- The transfer of thermal energy with no overall transfer of matter is called conduction.
- Conduction is slower in gases than in liquids and solids because the particles in a gas collide less often
- Conduction is faster in metals than in other solids because metals have free electrons that transfer thermal energy
- Thermal energy is transferred without transfer matter
- In most solids, conduction takes place as particles vibrate in place
Type of Material
| Quality of Conduction
| Two Examples
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2. Convection
- The transfer of thermal energy when particles of a fluid move from one place to another is called convection
- When a fluid circulates in a loop as it alternately heats up and cools down, an convection currents occurs
- Three examples of convection currents are ocean currents, weather systems, and movements of hot rock in Earth's interior
- Temperature is higher at the bottom of an oven because when the air at the bottom of the oven heats up, it expands and becomes less dense. Therefore the hotter air is at the bottom.
3. Radiation
- The transfer of energy by waves moving through space is called radiation
- In radiation, energy is transferred by waves
- All objects radiate energy. An example would be an electric heating coil on a stove. It radiates so much energy that it glows.
- The farther away you are from a radiating object, the less radiation you will receive
- Thermodynamics is the study of conversions between thermoenergy and other forms of energy
- Energy cannot be created or destroyed, but it can be converted into different forms
- Thermal energy flows spontaneously from hotter objects to cooler objects
- Thermal energy that is not converted into work is called waste heat
- Scientists have created a heat engine with 100 percent effciency by reducing the temperature of the outside environment to absolute zero
- The first law of thermodynamics states that energy is conserved.
- The second law of thermodynamics states that thermal energy can flow from colder objects to hotter objects only if work is done on the system.