Urine Trouble Now

sciencegeekgirl: If a boy pees on the floor and there’s nobody there to see it

The boys’ urinals were often surrounded by a puddle of “liquid.” Were the urinals weeping water? Or were the boys purposely urinating on the floor (as the janitor believed)? And, most importantly, how can we use our good friend SCIENCE to solve this mystery, the teacher asked?

Is there a powder I can sprinkle on the floor that will turn a particular color?
A UV light to shine on the puddles that will fluoresce?

It turns out that, yes, there is such a device!

Note that I have not deigned to confirm this effect with my own UV light.

However, I had read about the etched fly “targeting system” discussed; I had charged a friend of my brother’s with the task of finding one of these when he was in Europe. I had read they had been installed in the Amsterdam airport, but he didn’t see any there. This was taken at a restaurant in Berlin

fly_target

The Nougat has Cleared the Tower

There’s a fairly well-known science question which asks

How does the amount of energy per gram of TNT compare with the energy per gram of a chocolate chip cookie?

I’ve discussed before why I think the answer should be, “About the same,” if you’re doing a first-order approximation, and depending on what options you give for an answer.

We’ve also visited the energy content of a candy bar. So along that vein (or clogged artery) we have

Recrystallized Rocketry

which tests sugar as an ingredient in rocket propellant, in the form of pixy sticks, creme from an oreo cookie, and a Snickers bar.

Creme filling from one Double Stuff Oreo weighed out at 5.7 grams. Mixed with 11.4 grams finely powdered KNO3 (FireFox) with mortar and pestle.

Result: Burns very sluggishly, requires some assistance from torch flame

Adjustment: Added 0.2 grams red iron oxide (Fe2O3) to catalyze the burn. Works much better.