Actually he doesn't explain why, he just repeats the term "intermolecular polarity". What it means is that water molecules are polar; they have a positively charged side and a negatively charged side, and oil molecules are not. This means that water molecules are electrically attracted to other water molecules, but not so much to oil molecules, so the lowest-energy configuration is for all the water to be together.

Don't screw the cap on the bottle after the alkasetzer is added. You might shoot your eye out or lose a finger.

Seems like he might have wanted to stress the idea that you probably shouldn't cap the bottle until _after_ the alka-seltzer had completely dissolved.

I did something quite similar as a kid. All started when I got interested in chemistry at about 5, and my parents said: "Don't touch the 409 or the bleach, but everything else is fair game." Stuck every sorta-chemical I could find in a plastic baggie and watched it bubble. Real cool.

Does Alka-seltzer change the oil chemically into non-food? If not, the oil could be re-used for baking after we get bored with the 60s. Natural food dyes might be recommended.

One could keep their lava lamp on the pantry shelf, ready to whip up an ever-popular "Lava Lamp Birthday Surprise Cake."

Am I the only one a little irked that he referenced the different densities of oil and water to explain the lack of mixing? Ethanol, like oil, is less dense than water but it completely mixes. So density is not the answer of course but the intermolecular polarity referenced by the BoingBoinger.

ScienceBob, come on.

Surely this guy is somehow related to @hodgman! Not as witty, or as smart, from the example I see here… I hope I'm not finding seeing resemblance due to the haircut and glasses!

When I was a kid we used to put water and alkaseltzer into plastic bottles and cap them. Then we'd shoot them with a .22 and howl and laugh when they exploded (yeah, I confess, I'm white trash). I don't recall any of them exploding on their own though. They had plenty of time to pop too, I was/am a terrible shot.

I like doing the fully-consumable version: using a few raisins in a glass of clear soda. Admittedly, it's not as visually impressive as this version, but still fun to watch - and none of it goes to waste afterwards.

Interesting. Our Kidz Group will get a kick out of trying this experiment next week.

Brian