Morden's Laws of Spellcasting

"... From these experiments, the only logical conclusions are the following empirical equations:

1. For a magical effect to manifest, Caloric must be converted into ordinary, or extraordary, energy. If no caloric is present, the spell cannot take place.
2. The amount of caloric required to manifest an effect is proportional to the energy required to manifest the same effect through conventional means: dE = ξ³ đϚ, where dE is the change in energy (often in heat plus force), đϚ is the change in caloric and ξ is the amount of Animis acting as a conduit.
3. The flux (per second) of caloric throughout (one cubic metre of) space is constant: Φ(Ϛ) = Ϻ^ξ , where Ϻ is a constant and ξ is the amount of animis present within the area. One cubic metre of space holds roughly 6 times this amount of caloric

The amount of caloric stored in one cubic metre of space has been observed to be over 10²⁵ joules. The amount of this able to be manipulated by a normal spellcaster, however, seems significantly lower..." -Morden, from On scientifically quantifying the Art of Spellcasting