A Note on the Science of Phlogiston · 7:59am Mar 23rd, 2014
This is not essential to the story, and can be treated as a footnote. Or a hoofnote. Whatever.
Any energy can be condensed into physical form, given the right conditions. However, this is easiest with heat, giving us phlogiston. Radiation is also fairly easy.
Phlogiston is commonly known as fire, given form. It's a substance, the primary component of which is magical fire, which is either A) fire from the combustion of a magical object, or B) fire invoked from a magical spell. It seldom occurs naturally, and only under conditions of extreme heat and compression. Because of this, it is most often magically replicated.
The magical fire must first be stabilized, so that it can't go out when removed from a source of fuel. Then, it is compressed into a space that is tight enough to prevent escape or spread, forcing the energy to continually turn inward on itself. As the space gets tighter, the energy coils around itself; this is due to the property of magical cohesion, or the tendency for like magical energy states to stick together. Eventually, they form a continuous loop of transferring heat around a static center. As the energy loops on the outside are further compressed, they eventually reach the point of condensation, the point at which they form a near-perfect circle, with no energy pressing against the walls. This is called an energy-form particle. These are typically between .5 and 1 millimeters in diameter.
Because the energy-form particles are only stable under compression or, to a lesser extent, cohesion, they break apart when exposed to open air. This is why the phlogiston fizzed in its bottle; the surface of the liquid, exposed to air, began to lose its energy. It is usually contained in thin-necked bottles to decrease surface area, and therefore speed of loss.
In heating it up, Fluttershy had to mix it in water to dilute it, and therefore increase the temperature at which it becomes dangerous. Mixed in a low enough concentration, the phlogiston's point of evaporation is lower than its point of explosion. The water is distilled so as not to introduce foreign particles into the compound.
Pinkie was exaggerating when she said that phlogiston on the fur would make you blow up. It only makes you catch on fire.
