[MarkPawelek]

Cold is the absence of heat, and energy. Simplest way to explain it is: when something gets colder its because the energy moved away. Every warm thing radiates energy away all the time according to the Stefan–Boltzmann Law (AKA Stefan's Law). Electrons in higher energy orbitals literally move to lower energy orbitals and emit photons which radiate away.

Other examples of warm things (with more potential energy) getting colder are:
conduction, convection, loss of kinetic energy, transformation of state (e.g. a liquid takes warmth from its immediate environment and uses it to change state - to a gas) as latent energy, and nuclear radiation.

Radioactive decay is an interesting one. Here the thing with greatest potential energy has a less stable neutron to proton ratio in its atomic nucleus. It "decays" to a more stable ratio, and emits alpha, beta, and/or gamma radiation. It loses nuclear binding energy which is emitted as energy during its decay. Nuclear fission and fusion are 2 more examples of things with more potential energy transforming to things with less potential energy.

Notice the trend - loss of energy, or, better, sharing it out, is the natural state of things. It's a bit like utopian socialism : at the end of the day everything gets to be equal (in energy) with everything else. There should be a law for that, and there is.

[Monox D. I-Fly]

Notice the trend - loss of energy, or, better, sharing it out, is the natural state of things. It's a bit like utopian socialism : at the end of the day everything gets to be equal (in energy) with everything else. There should be a law for that, and there is.

So... Long story short, energy is a communist?

[hamdani yusuf]

Feeling cold is about losing heat. You can feel colder when touching 10º C water compared to 0º C dry air due to their difference in heat conductance.