Energy and HeatEnergy is the ability to do work on matter. The work done is manifested in a variety of ways. Matter can be pushed, pulled, or lifted over distance when energy is applied. In other words, work done on matter implies a change of position or movement. Potential energy is the energy of position. A block of rock attached to a high cliff face has substantial potential energy due to its position above the ground. When it breaks away from the cliff and falls to the surface potential energy is converted into kinetic energy of motion. When the rock hits the ground, kinetic energy is converted into work when it dislodges surface material.
Heat is the total energy associated with random atomic and molecular motions of a substance. Heat is transferred in three ways. Radiation is the transfer of energy via electromagnetic waves. Radiation does not need an intervening medium to pass heat energy from the emitter to the absorber. When radiation from the Sun is absorbed by the Earth it does work by setting molecules in motion and raising their kinetic energy level. In a solid, the molecules may vibrate more rapidly and collide with one another and transfer heat from warmer to colder portion of the mass by conduction. In fluids like air and water, heat is transferred by the circulation of molecules via the process of convection. The calorie is used as a unit of measurement for heat. A calorie is the amount of heat required to raise the temperature of one gram of water through 1oC. Energy is also expressed in terms of joules. One joule is the equivalent of one watt of power radiated or dissipated for one second. Temperature is a measure of the average kinetic energy level of a substance, in other words, the degree of hotness or coldness. Don't think temperature and heat are the same thing. A boiling pan of water has a higher temperature than a tepid bathtub of water, but the tub contains more heat because there is more mass. |
