Coke + Rust = Results!

The results of this little experiment were actually not bad. Upon opening the container of Coke today I saw two small patches of gunk floating on the surface. These turned out to be directly above the screws, as expected. The bubble plumes mentioned in the previous post were also still present, though they were much smaller.

Once the coke was drained, I realized one mistake I’d made during the experiment. Both of the screws had been placed with the flat side of the head facing downwards, against the bottom of the container. I think this the reason for why the heads are still very rusty, as seen in the photos that follow. In both images the one on the right was the untreated screw.

The things coming out of the Coke weren’t brand new and shiny, but there was a bit of improvement. It’s also possible that leaving them in longer would clean off more rust.

T

Coke + Rust = ??

This is a bit of a deviation from what I normally blog about, but we have a ton of extra Coke cans at home and I nobody drinks it. I’ve heard a few times that Coke (well, the chemicals in Coke) are excellent at doing things like dissolving calcium, removing rust, etc. I figured I’d give the rust a try.

The hardest part by far was finding enough identical rusty objects. I wanted at least 2; one control and one to actually soak in the Coke. I ended up having to use these:

The container was just an empty yogurt container, which happened to be the perfect size:

I ended up tossing 2 of the rusty screws into the Coke, keeping the third out for comparisons. As soon as the screws hit the liquid sizable plumes of bubbles started forming around them, and continue even as they settled on the bottom of the container. I’m not sure if this was just CO2 escaping due to nucleation or some sort of reaction between the rust and the Coke. I also put the lid on the container, which had some interesting implications. Within the first minute or two the lid was bulging and pressure was seeping out from the rim of the lid. Again, I’m not sure if this is entirely regular Coke behavior or not. Either way, I added air holes in the lid.

I’m going to check back in a couple of hours to see what’s happened, and then again tomorrow morning and afternoon. I’ll post the results then.

T