Science of steel wool photography, “The 9 volt battery is used to ignite the steel wool. Essentially it sends a current through the thin wire and it heats up, well under statement a LOT … to about 700 degrees celsius. These insane temperatures cause the iron to react with oxygen in the air creating iron oxide. This reaction releases heat, which heats up the next strand and so on, causing a cascading reaction across the steel wool. When you’re doing this remember the science.”
The chemical reaction requires oxygen. So fluffing it up and spinning it., increases the amount of oxygen available hence speeding up the reaction and giving the amazing photos at the end.