Electrolysis, water, and various metals

[OmCheeto]

I did an experiment, prompted by another thread, and saw something you kids probably see all the time:

I was trying to measure the resistance of seawater, and came up with ≈11Ω. End of experiment, or so I thought...

But then I decided that my battery voltage was a bit low and decided to charge it up properly with my 1200 watt charger.

When I was doing this, I decided to do another experiment, and plunged the battery post sized alligator clips into the water for a moment, and saw that the electrolysis effect was about the same. meh. Nothing exciting there. So I went back to charging the battery.

When I came out 30 minutes later, the water in my pyrex was rust colored, and there was a 1/4 inch precipitate of rust colored stuff at the bottom.

I was once again puzzled, and did it again. I plunged the clips into my pseudo-ocean water, and several seconds later, the water turned almost black!

That was a bit ago, and when I went out again, the rust had precipitated to both the top and bottom, there was a black film around the top, and the middle was semi-clear.

I imagine that with chrome plated steel clips crimped to copper wiring attached to lead posts in an oxygen laden atmosphere, that the fluffy white stuff I saw disappear during this 2nd half of my experiment were some types of metal-oxides.

hmmmm...

Sorry for the rant, but if anyone knows why the water turned black, I won't have to google that in the morning.

Thanks!

 

[Zefram]

Hello,

First of all, thank you for sharing your experiment with us. It is always exciting to see someone actively engaging in scientific inquiry.

Based on your description, it seems like you have observed the process of electrolysis in action. When electricity is passed through a liquid, it can cause a chemical reaction to occur. In this case, the electricity from the battery is breaking down the water molecules into hydrogen and oxygen gas. The oxygen gas then reacts with the metal in your alligator clips, causing the rust-colored precipitate to form.

The reason why the water turned black is likely due to the formation of iron oxide (also known as rust) from the reaction between the oxygen and the metal in the alligator clips. The fluffy white stuff you saw disappearing could also be a result of this reaction.

Overall, your experiment has shown the importance of understanding the chemical properties of the materials we use in our experiments. It is also a great reminder of how even small changes, like using a fully charged battery, can have a significant impact on our results.

I hope this helps answer your question. Keep up the great work and keep exploring the world of science!