Heat and Heat Transfer Flashcards
Definition of heat:
Movement of thermal energy from a substance at a higher temperature than another with a lower temperature.
- Matter does not contain heat, it contains thermal energy
How is heat transferred?
By conduction, convection and radiation
What is conduction?
Transfer of heat between substances that are in direct contact with each other. Heat is transferred from one particle of matter to another without the movement of matter itself. The better the conductor the better heat will transfer.
What is a conductor?
Material / substance that transfers thermal energy easily
What is an insulator?
Material / substance which does not transfer thermal energy
What is convection?
Up and down movement of fluids caused by heat transfer. As fluid is heated it warms, becomes less dense and rises. As fluids are cooled it contracts, becomes more dense and sinks.
What are convection currents?
Heating, cooling, expanding and contracting process creates this.
What is radiation?
Transfer of energy by electromagnetic waves. Radiation does not require matter to transfer thermal energy. (When something radiates it spreads outwards from an origin. The sun shining heat on Earth is by radiation.)
The hotter the object the more it radiates. All objects radiate energy in the form of electromagnetic waves.
What is temperature?
Measure of the average kinetic energy in the individual particles of an object
What is thermal energy?
Total energy (internal energy) of a substances particles due to their movement. Depends on substances temperature, number of particles (in amount) and particle arraignment.
