It's not unusual for students who see this demonstration to claim that the "red stuff" is rust (meaning the compound iron III oxide). Brainstorm some empirical data (information that you could collect in the lab) that would prove or disprove the claim that the "red stuff" is rust.

Rust is muddy red in color.

Explanation:

When iron or iron alloys are exposed to atmospheric air which contains moisture, it gets oxidized and forms rust. Rust is not desirable. The piece of iron converts into iron oxide when it is exposed to moisture or oxygen due to oxidation reaction.

Rust gives a flaky reddish brown color to the metal and it becomes more worse over the time. Rust consists of hydrated iron (3) oxides i.e. and iron(III) oxide-hydroxide i.e. .