h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Or Fablon, as everyone who doesn't work for the BBC calls it.

http://www.youtube.com/watch?v=QOzdcM-YZ2U

I'm little confused about this. Is the jelly there to give a solid flat base from where the rain is measured? In which case why hasn't she said to put it in the fridge to set? And besides, jelly is water-soluble so it'd start to dissolve as soon as any rain got in there and you'd get a false reading. I'm sure there must be other compounds that could be used to fill the base and give a flat surface. Modelling resin perhaps? Cement? Plaster of Paris? Put some potters clay in the bottom and leave it in the sun for a week to harden?

Or maybe the jelly remains liquid and you just measure the amount of extra liquid which has been added to it as the rain fell. In which case you could just stick the ruler to the side of the bottle anywhere above the uneven part of the base and add water until it reaches the zero point on it, then put your gauge out and wait for rain. But some of the water might evaporate before it rains, or condense on the inside of the bottle, and you'd get a false reading. Perhaps the jelly prevents the water from evaporating quite so quickly?

Either way, if you have to refill your jelly rain gauge several times a week I'm investing in jelly manufacturer shares

Yep. That was clear as mud.

Even if the jelly (that's what we call by the brand name, Jell-O, right?) doesn't dissolve in or absorb rain water, I suspect after a few days out in the weather and sun it would shrink and crack. And I agree that other things would work better. I think I'd just fill the bottom with maybe an acrylic paint, epoxy or similar substance.

Oh, and she does the sloppiest job of lining the ruler up with the top of the jelly. When you're making a how-to video for kids, that doesn't mean it should look like a kid built the thing you're demonstrating.

Also, that design means you'll have to remove the funnel made from the bottle top to dump it. Why put it in there in the first place? It is doing nothing except maybe preventing a negligible amount of evaporation.

Now where does this "Fablon" stuff come in?

Fablon is (was?) a decorative plastic sheet that came in rolls and had adhesive on the back so you could stick it to things. I remember it being used a lot to cover kitchen shelves because, being plastic, it was easy to clean and non-porous.

It became a bit of a joke (and has now entered the language) because of a BBC kids show. They'd often come up with projects for kids to make (like this http://www.youtube.com/watch?v=Yq9vQJBpuNA ) which usually involved Sqezy* bottles or Fablon (often both), except they couldn't call it Fablon or Sqezy because that's a brand name, and you know how the BBC hates that sort of thing, so it was always washing-up liquid bottles and sticky-backed plastic.

Ha, the second Google search suggestion for Fablon is sticky back plastic

*Yes, it really is spelt like that http://www.modip.ac.uk/sites/modip/images/large/006287_1.jpg but after calling it 'squeezy' for long enough you seem not to notice the missing letters.

Ah... OK... it was a cultural issue I was missing.

Oh, and I always just knew of that stuff as "shelf paper". My mother used it to line her kitchen shelves. I never really knew why, what purpose it filled, but every few years she'd buy new shelf paper and cover her cabinet shelves with the ugliest flowery patterns.

Yeah, there were some pretty garish designs. And some very 1960s designs too, which, if you still had any rolls stashed away at the back of the cupboard under the stairs, would have hipsters wetting their knickers (and skinny jeans).