"Is it still matter?"
"Yes."
"Is it the material of the iron, or is it the energy called heat that qualifies the strength of the metal? It seems to me that were I in your place I would now argue that absence of heat constitutes strength," he sarcastically continued.
"Go on."
"Cool this red-hot poker by thrusting it into a pail of cold water, and it becomes very hard and brittle."
"Yes."
"Cool it slowly, and it is comparatively soft and plastic."
"Yes."
"The material is the same, is it not?"
"Go on."