On Tue, 14 Dec 1999 16:49:14 -0000 Rob Harris <rob@hbinternet.co.uk>
writes:
> Something that interested me greatly popped into my head the other
> day. I was wondering about the relationship between energy and heat.
I've
> studied A level physics, and I don't have the faintest idea of the
answer to
> this, so all you physics masters out there, lend us a brain cell for a
> minute. What exactly is the difference between energy and heat ?
In a nutshell, all heat is energy, but not all energy is heat. Heat is an abstract form of energy, rather arbitrarily defined. Energy comes in many different forms or manifestations, but on a fundamental level there are only a very few basic forms of energy, as there are only a few fundamental forces or fields. Heat per se is not considered a fundamental form of energy, as heat is defined in terms of kinetic energy and electromagnetic energy. Heat is the energy ascribed to a set of material particles within a compact space due to the random motion of those particles within the limited space, along with the kinetic energy of the internal mechanical vibration within the structure of each of the particles, along with the electromagnetic energy within the space and material, some of which is the instant potential electromagnetic energy of the excitation of the atoms, and some of which is the instant energy of the electromagnetic flux within the space. The heat energy of a block of matter within a space is the sum of the kinetic energies of each of its constituent particles, relative to the reference frame of the block as a whole, plus the electromagnetic energy within the material and the space. Heat is diffused kinetic and electromagnetic energy within a body, as opposed to the gross kinetic energy of the body in gross motion. Sometimes, though, a single particle in motion, such as an electron in a CRT, is assigned a temperature based on its motion relative to a reference frame external to the particle, though clearly, the electron has no kinetic energy in its own reference frame.
Ron Kean
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