Homeschool High School Chemistry: Electrolysis of Water Lab

Another day, another kitchen table chemistry lab!

I don't know what the "proper" number of hands-on labs a high school student usually conducts in a non-AP Science class is (in her year of public school Honors Biology, my own teenager conducted one), but in our homeschool high school honors science classes, I try for at least ten high-quality labs, experiments, and/or demonstrations, all written up by the student in her lab notebook for that subject. 

And they don't have to be complicated! This Electrolysis of Water lab could be conducted by an early elementary student, it's so simple. It takes just minutes, and it's easy as pie to conduct at the kitchen table.

To make it appropriate for a high school Honors Chemistry lab, just add rigor! When she completed this lab, my teenager was studying Lewis Electron-Dot Structures and calculating chemical reaction formulas, so I wrote her Post-Lab Questions to require her to practice these skills in a real-world environment.

In AP Language and Literature, she's looking deeper into the etymologies of words, so I also included a question about that to build context. 

Here's the set-up for the lab (pretend that you don't see the erasable pen that my teenagers like to use to cheat the lab notebook system of "write in pen; no erasing"):

Salting the water to the proper ratio (feel free to admire the chopstick stirring rod...):

Attaching the wires to the battery (the electrodes are currently touching, but she'll fix that as soon as she notices):

And now... observation! I always think that this is the coolest, most magical demonstration. Look at all the bubbles!

A surprise to us all: we didn't expect the aluminum to start flaking away! 

Is it an aluminum oxide coating on the foil? A manufacturing flaw resulting in improper adhesion of the aluminum that weakens it?

My favorite thing about science is the way that new information inspires new questions!

If that's not enough electrolysis for you, here are a few extension activities:

• incorporate Snap Circuits. I actually thought pretty hard about incorporating part of this demonstration, because we have sooooo many Snap Circuits. This would be an especially good extension if your focus is actually on electricity. 
• incorporate a pH indicator. This is a neat addition, especially if you've recently studied pH. Red cabbage pH indicator is another excellent homeschool DIY project!
• clean iron. The Children's Museum of Indianapolis has a giant electrolysis tank where you can observe the real-time process of rust removal from one of Captain Kidd's cannons, so you can observe this real-world bit of science in action even if you don't have your own iron to clean via electrolysis.

And here are a couple of books that include similar electrolysis experiments. The Marie Curie book is even written TO middle-grade kids!

And there you have it: excellent science using household materials in just a few minutes. With that little time spent on the actual lab, you've got plenty of room to really ramp up the rigor of the post-lab questions!

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