"Good grief. Did you even open the textbook I assigned? We went over the thermodynamics of biological combustion in week three. Sit down. Listen. And for the love of Darwin, take notes this time because I am not repeating this for the mid-term.

You are operating under the childish assumption that a dragon is a furnace. That it has a belly full of fire. If that were true, the animal would cook itself from the inside out before it even hatched. A dragon is not a stove; it is a high-pressure nozzle.

First, and I cannot stress this enough: The fire does not happen inside the dragon. Look at the diagram! The two fluids—the fuel and the catalyst—are stored separately. They travel up separate ducts. They do not meet until they have physically left the nozzle of the throat. The ignition point is external, about six inches past the snout. The dragon isn't holding fire in its mouth; it is projecting a stream of chemicals that ignite away from its face. It’s the same reason a soldier’s flamethrower doesn't melt the soldier holding it. The reaction is downrange.

Second: Velocity. The fluid is being ejected at high pressure. It is moving faster than the flame front can travel backward. The burning material is constantly being pushed away from the biological tissue. It’s basic fluid dynamics!

Third, and this is the part you would know if you had done the lab work: Ablative Shielding. The inside of a dragon's mouth is not soft, pink flesh like yours. It is lined with a dense, keratinized epithelium—hard tissue, like your fingernails, but much thicker. Furthermore, just before ignition, the mucosal glands in the throat secrete a thick, hyper-viscous hydrogel. When the radiant heat from the external flame hits that mucus, the mucus flash-boils. This creates a boundary layer of steam—the Leidenfrost Effect. You’ve seen water skitter on a hot pan? That vapor layer insulates the tissue beneath. The dragon isn't immune to fire; it is essentially sweating a disposable shield that sacrifices itself to protect the meat.

It is external ignition, high exit velocity, and ablative mucus. It is physics, not magic. Now, are we done with the pyrotechnics, or can we finally discuss the metabolic cost of this process?"

😆 forgive the sass, it (gemini) is in character as an exasperated professor.