Speaker 1: Welcome to brainstuff front House, stuff works dot Com, where
Speaker 1: smart happens by a Marshall brain with today's question how
Speaker 1: does rust work? Rust is the name that we use
Speaker 1: for a very common compound iron oxide. Iron oxide, the
Speaker 1: chemical F E two O three is common because iron
Speaker 1: combines very readily with oxygen, so readily, in fact, that
Speaker 1: pure iron is only rarely found in nature. Iron or
Speaker 1: steel rusting is an example of corrosion, an electrochemical process
Speaker 1: involving an anode, or a piece of metal that readily
Speaker 1: gives up electrons, an electrolyte, a liquid that helps electrons move,
Speaker 1: and a cathode a piece of metal that readily accepts electrons.
Speaker 1: For iron to become iron oxide. Therefore, three things are
Speaker 1: acquired iron, water, and oxygen. Here's what happens when the
Speaker 1: three get together. When a drop of water hits an
Speaker 1: iron object, two things begin to happen almost immediately. First,
Speaker 1: the water, a good electrolyte, combines with carbon dioxide in
Speaker 1: the air to form weak carbonic acid and even better electrolyte.
Speaker 1: As the acid is formed and the iron dissolved, some
Speaker 1: of the water will begin to break down into its
Speaker 1: component pieces, hydrogen and oxygen. The free oxygen and dissolved
Speaker 1: iron bond into iron oxide in a process that frees electrons.
Speaker 1: The electrons liberated from the anode portion of the iron
Speaker 1: flow to the cathode, which may be a piece of
Speaker 1: metal less electrically reactive than iron, or another point on
Speaker 1: the piece of iron itself. The chemical compounds found in
Speaker 1: liquids like acid rains, seawater, and salt loaded spray from
Speaker 1: snow belt roads make them better electrolyte. It's the pure
Speaker 1: water allowing their presence to speed the process of rusting
Speaker 1: on iron and other forms of corrosion on other metals.
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