WEBVTT - How does rust work?

0:00:00.600 --> 0:00:03.920
<v Speaker 1>Welcome to brainstuff front House, stuff works dot Com, where

0:00:03.920 --> 0:00:15.400
<v Speaker 1>smart happens by a Marshall brain with today's question how

0:00:15.440 --> 0:00:19.479
<v Speaker 1>does rust work? Rust is the name that we use

0:00:19.640 --> 0:00:24.680
<v Speaker 1>for a very common compound iron oxide. Iron oxide, the

0:00:24.760 --> 0:00:29.200
<v Speaker 1>chemical F E two O three is common because iron

0:00:29.240 --> 0:00:33.440
<v Speaker 1>combines very readily with oxygen, so readily, in fact, that

0:00:33.560 --> 0:00:37.879
<v Speaker 1>pure iron is only rarely found in nature. Iron or

0:00:38.080 --> 0:00:43.080
<v Speaker 1>steel rusting is an example of corrosion, an electrochemical process

0:00:43.200 --> 0:00:46.400
<v Speaker 1>involving an anode, or a piece of metal that readily

0:00:46.479 --> 0:00:51.480
<v Speaker 1>gives up electrons, an electrolyte, a liquid that helps electrons move,

0:00:51.640 --> 0:00:55.840
<v Speaker 1>and a cathode a piece of metal that readily accepts electrons.

0:00:56.360 --> 0:01:00.000
<v Speaker 1>For iron to become iron oxide. Therefore, three things are

0:01:00.000 --> 0:01:04.400
<v Speaker 1>acquired iron, water, and oxygen. Here's what happens when the

0:01:04.440 --> 0:01:07.640
<v Speaker 1>three get together. When a drop of water hits an

0:01:07.640 --> 0:01:11.959
<v Speaker 1>iron object, two things begin to happen almost immediately. First,

0:01:12.040 --> 0:01:15.960
<v Speaker 1>the water, a good electrolyte, combines with carbon dioxide in

0:01:16.000 --> 0:01:20.960
<v Speaker 1>the air to form weak carbonic acid and even better electrolyte.

0:01:21.360 --> 0:01:24.679
<v Speaker 1>As the acid is formed and the iron dissolved, some

0:01:24.800 --> 0:01:27.040
<v Speaker 1>of the water will begin to break down into its

0:01:27.040 --> 0:01:31.840
<v Speaker 1>component pieces, hydrogen and oxygen. The free oxygen and dissolved

0:01:31.920 --> 0:01:36.920
<v Speaker 1>iron bond into iron oxide in a process that frees electrons.

0:01:37.319 --> 0:01:40.640
<v Speaker 1>The electrons liberated from the anode portion of the iron

0:01:40.720 --> 0:01:43.399
<v Speaker 1>flow to the cathode, which may be a piece of

0:01:43.440 --> 0:01:48.000
<v Speaker 1>metal less electrically reactive than iron, or another point on

0:01:48.080 --> 0:01:52.080
<v Speaker 1>the piece of iron itself. The chemical compounds found in

0:01:52.160 --> 0:01:56.960
<v Speaker 1>liquids like acid rains, seawater, and salt loaded spray from

0:01:57.040 --> 0:02:00.680
<v Speaker 1>snow belt roads make them better electrolyte. It's the pure

0:02:00.720 --> 0:02:04.360
<v Speaker 1>water allowing their presence to speed the process of rusting

0:02:04.440 --> 0:02:08.840
<v Speaker 1>on iron and other forms of corrosion on other metals.

0:02:08.880 --> 0:02:11.560
<v Speaker 1>For moralness and thousands of other topics, is it how

0:02:11.600 --> 0:02:16.680
<v Speaker 1>stuff works? Dot com