Coke-Propane Rocket Blasts Off Without Ignition

Everyone’s seen the Diet Coke and Mentos “experiment” that ends in a brown eruption. But have you seen the Coke and Propane experiment insanity that results in a rocket launch? As [Itay] pointed out when he sent us the tip, this doesn’t need to be lit. The simple act of turning the bottle upside down starts a powerful reaction without any ignition.

coke-propane-rocket-thumbOf course it’s the how of this that tickles our brains, but let’s finish the setup. This starts with a bottle of Coke which is about 3/4 full. The head space is displaced by spraying propane into the bottle; propane is heavier than air. All that’s left is to turn the bottle upside down and pray it doesn’t smack anyone in the noggin as it takes off.

In trying to find an explanation for this phenomenon we came across a plausible answer on the Chemistry StackExchange. It points to the Mentos phenomenon combined with the temperature differential caused by the very cold propane. The answering user theorizes that tiny ice crystals form and when the bottle is turned upside down the cold propane and micro crystals rise through the warmer soda acting as a much more rapid catalyst than Mentos alone. Of course this is just a theory so please share your own ideas below.

We thought the folks who microwave stuff outside of a microwave enclosure had their fill of danger but this videos is also one of theirs. It should be no surprise that they also tried the experiment with an ignition source. That video is found after the break and should immediately convince you to never try any of this yourself.

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I got 99 volts and my anodizing’s done!


[POTUS31] had a need for anodized titanium, but the tried and true “submersion” method was not going to work out well for what he was trying to do. In order to create the look he wanted he had to get creative with some tape, a laser cutter, Coke, and a whole lot of 9v batteries.

His Ring-A-Day project has him creating customized rings based on reader feedback, and lately the requests have had him searching for a good way to color metal. Anodizing titanium was a sure bet, though creating detailed coloring on a small medium is not an easy task.

[POTUS31] figured that he could gradually anodize different areas of the ring by using laser-cut tape masks, allowing him to selectively oxidize different portions of his creations as he went along. Using the phosphoric acid prevalent in Coke as his oxidizing agent along with a constantly growing daisy-chain of 9-volt batteries, he had a firm grasp on the technique in no time. As you can see in the picture above, the anodizing works quite well, producing vivid colors on the titanium bands without the need for any sort of dye.

[POTUS31’s] favorite color thus far? A rich green that comes from oxidizing the metal at you guessed it – 99 volts.

[via Make]

Anodize titanium at home

We don’t really have any titanium lying around, it’s not exactly a cheap material. But this hack that shows you how to anodize titanium in your home laboratory (or kitchen for that matter) and it might help the metal make its way into a future project. It seems the process is not overly difficult or dangerous and it’s possible to achieve a lot of different colors in the finish.

In the image above [PinkFlute] is using Coke Zero, a sugar-free soda, as the chemical agent in the process. The alligator clip attached to the utensil is providing the positive voltage and the yellow wire dipped in the drink is negative. Finish color is determined by the voltage supplied. You can choose various shades of green, purple, yellow, and blue based on a voltage range of about 100V to 20V.

This is one of two anodizing methods shown. the other uses a foam brush dipped in soda with the negative lead clamped onto it. You just brush in the electrified substance to alter the camping spork’s finish.

[via Reddit]