CT: Heat and Thermal Energy:
- Heat – an energy transfer that occurs because of a difference in temperature.
- Internal Energy – the energy a substance has because of its temperature.
Energy may be transferred between two objects without heat flow.
Example: rubbing two coins together. Both internal energies are increased due to mechanical work but both remain in thermal equilibrium throughout.
Units of Heat:
- Calorie – the amount of heat energy required to raise the temperature of 1 gram of H2O from 14.50ºC to 15.50ºC. A food calorie is 103 “physics” calories
- BTU – the amount of heat energy required to raise the temperature of 1 lb. of H2O from 630ºF to 640ºF.
- Joule – the S.I. unit of heat and work.
1 calorie = 4.186 Joules = 3.9 × 10-3 Btu.
S: http://www2.cose.isu.edu/~hackmart/Thermodynamics_2.pdf (last access: 1 February 2015)
N: 1. heat (n): Old English hætu, hæto “heat, warmth; fervor ardor,” from Proto-Germanic haita- “heat”, from PIE kaid-, from root kai- “heat.” The same root is the source of Old English hat “hot” and hæða “hot weather” (see hot).
energy (n): 590s, “force of expression,” from Middle French énergie (16c.), from Late Latin energia, from Greek energeia “activity, action, operation,” from energos “active, working,” from en “at” + ergon “work, that which is wrought; business; action”.
Used by Aristotle with a sense of “actuality, reality, existence” (opposed to “potential”) but this was misunderstood in Late Latin and afterward as “force of expression,” as the power which calls up realistic mental pictures. Broader meaning of “power” in English is first recorded 1660s. Scientific use is from 1807. Energy crisis first attested 1970.
2. Energy in the form of heat.
3. Heat energy (or just heat) is a form of energy which transfers among particles in a substance (or system) by means of kinetic energy of those particle. In other words, under kinetic theory, the heat is transfered by particles bouncing into each other.
In physical equations, the amount of heat transferred is usually denoted with the symbol Q.
4. Thermal energy is the energy that comes from heat. This heat is generated by the movement of tiny particles within an object. The faster these particles move, the more heat is generated. Stoves and matches are examples of objects that conduct thermal energy.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=heat&searchmode=none; http://www.etymonline.com/index.php?allowed_in_frame=0&search=energy&searchmode=none (last access: 1 February 2015). 2. TERMIUMPLUS. 3. http://physics.about.com/od/glossary/g/heat.htm (last access: 1 February 2015). 4. http://www.softschools.com/facts/energy/thermal_energy_facts/402/ (last access: 1 February 2015).
SYN: thermal energy