Each concept here is mapped to its prerequisites — the ideas you'd need first to understand it — all the way down to four foundations: Space, Time, Energy, Pattern. Click any prerequisite to drill down, or scroll for the chain graph.
A spark is a tiny glowing particle that carries a small burst of energy, which is the capacity to cause change or motion in a physical system, and is often thrown off from a fire, a process that requires combustion and heat.
External reference — all senses of the word “Spark” on Wiktionary. This atlas concept maps to only the slice of meaning relevant to the prerequisite graph.