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A 13 c Rust protection by plastic coating

* Left and photo 2: Burn the plastic coating by holding a piece of a Cola can above the flame of your burner.                     Please wear goggles for the next experiment! Ask an adult to join you!
* Photo 3: Keep the piece of Cola metal in hydrochloric acid (20 %). Aluminium is corroded very quickly, for iron it will take 1 day. Observations: The outer red coating and the inner transparent one separate from the metal.
 * Right: Most of the metal is corroded by the acid, the plastic layer did not change