Nichtlineare optik und lichtmodulation

Back in early April, I read on BoingBoing about the effects of adding Mentos to Diet Coke, which allegedly resulted in a carbonic geyser. I was somewhat sceptical and couldn't work out why the effect would only apply to Diet Coke. It looked cool, but as I don't have a garden in London I figured I wouldn't be able to try it out. Just in case it did actually work I decided not to try it out in the kitchen.
So anyway, I carried on about my normal business and tried not to think about this curious candy and cola conjecture. But last week I found myself back in Cardiff with not one but two gardens at my disposition (front and back gardens in the jargon). So last Saturday afternoon I went ahead and bought two bottles of Diet Coke and engaged in a wild goose chase to find some Mentos in North Cardiff (it wasn't that wild, I ended up finding some packets in local newsagents as opposed to a branch of a national supermarket).
As you can see from the freeze frames, it worked very well. You can see my surprise at this fact by the fancy footwork I had to use in order to get away from the soda jet as it threatened to erupt in my face.
Generally each eruption released about 1.5L of Diet Coke over my parents lawn. When I go back in the summer I'll let you know what effect this has had. When I tried to seed a further shower by adding more Mentos, it only had the effect of causing a slow and disappointingly undramatic bubbling. I tasted some of the left over Coke; it tasted like that new lime coke. I wasn't impressed.
I'm guessing that the Mentos provide bucket loads of nucleation sites for bubbles and fall fast enough through the coke that they form bubbles quickly enough at the bottom of the bottle that it pushes the rest of the liquid out the top. Still doesn't explain why it allegedly only works with Diet Coke.
I would have bought some regular coke to check this out, but after spending £3.04 on the diet coke and mentos, I was already 4 pence over my budget for cola related experiments this financial year.

I took some revision back to Cardiff, but in the end I didn't do any. Really needed the rest. Apart from adding mentos to diet coke in Cardiff, I spent some evenings in the Club Metropolitan catching up with friends, read some books, did some cycling and slept. Alot.

One of the books I picked up from the bookshelves at home was Clochemerle. As soon as I read the description on the jacket I knew that I would regret not reading this book:
"It is a candid, uninhibited comedy of the goings-on in a small provincial town, and of the fantastic feuds which developed from the decision to erect a public convenience near the parish church"
Just in case I wasn't convinced, the publishers noted that it was "one of the most amusing" books they had ever published. Sure, that was in 1951 and this last half century hasn't been bad for comedy, but to be honest they already had me. Those 1950s marketers sure knew a thing or two about making someone buy a book.
It hasn't disappointed, although after reading just a few chapters you just want to kick back with a glass of French wine, shrug your shoulders and adopt an altogether more Gallic attitude to life.

Finally, a number of readers (namely, zero) have contacted me outlining their suspicion that my blog was turning into a TBR's Martin Archer fan blog. It is true that I have prided myself on being first with all the latest gossip about this Imperial College celebrity from the people in the know (basically my housemate Andy and myself). But it turns out that this is no longer the place to turn for the inside scoop on TBR's Martin Archer because there is a new Martin Archer Fan Blog on the interweb, written by none other than Martin Archer himself! If I were you, I would go ahead and subscribe to the RSS feed post haste.