This video - without narration - would be a great, short (2.5 minutes total) introduction to how sacrificial anodes work to protect metals. In particular, there's a brilliant animation showing how electrons flow from a buried anode to protect a pipe from corrosion.
I don't have much else to say.
The video is simple, and I'll let my post be the same.
I was recently searching online for some better images of sacrificial anodes for our material science slideshow at school, and I thought I might as well put these out there for any other science teachers using the blog.
I will say in advance that I didn't take any of these, and that's why I'll be linking to the source. All were accessed in January and February of 2020. The links may rot, but I'll keep the images up.
If you don't, you might want to check out Landmark Home Warranty's great webpage explaining the usefulness of and science behind hot water heater anode rods.
There's even an infographic in case you don't like so many words.
Here Rich gives us a quick lesson in the anatomy of a hot water heater and - more importantly for materials science - the anode. He does a wonderful job explaining what an anode is (the sacrificial part of the heater) and describes it as being made of the 'least noble metal that we can put in [the heater]".
He also does a great job actually showing us how to replace an anode rod. He doesn't, however, address the question asked of where to buy a new anode.
This guy's no Rich Trethewey, but he does a good job showing how to change an anode in a far tighter space - with the hot water heater actually installed as opposed to Rich's magic 'in the middle of my shop' heater.
This video kicks Rich's hiney in terms of the science explained. I love the test for electrical conduction at 2:50. It's a neat little check to show us that the cell ACME is in place. This video also goes into far more of the chemistry of corrosion from about 3:30 onward, especially writing the reactions for the oxidation of iron. I would've never thought of using an electrically powered anode for a hot water heater. I wonder where that might be required.
By the way, has anybody ever heard the phrase (from 1:22) that two things can be lying "side by each"?
