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

by Stephanie Chasteen on September 26, 2009

We see the darndest questions on teacher listservs. It seems that, at one school, there was a mystery to be solved. 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!  Specifically created to detect pet urine stains, the Rug Doctor is here to help (and so are a plethora of other products).  It’s a blacklight, and it turns out that certain molecules in urine (just like in semen and blood) will fluoresce.  They use this at crime scenes too.  “Fluorescent” means that a material absorbs light of one color, and then re-emits it in another color.  Blacklight is ultraviolet, which is highly energetic light that is “too blue” for us to see.  The fluorescent molecules absorb that light, which loses some energy in the process, and re-emit it in as light that’s lower energy (that we can see).

I used to study some fluorescent polymers that fluoresced in room light.  They were beautiful.  The liquid in the little vial seemed to glow (well, it did glow), this kind of chartreuse.  The picture here isn’t from my research, but similar material.

Here are some common materials that glow under blacklight.

Anyway.  Back to the problem at hand.  We weren’t quite sure how these blacklight devices would work for detecting urine in tile grout (which probably holds all kinds of things). And how would one know if you were detecting backsplatter, or intentional misbehavior?

One teacher helpfully added:

A couple solutions I’ve seen to encourage boys to aim properly- in a bathroom at a truck stop in Alaska, there were the normal plastic filter things over the drain, but they had a little propellor thing labeled “Restroom Roulette” If you directed the stream at it, it would spin around until you stopped and point at various things like “You’re a Winner!” or “Sorry, try again” etc.  Most kids would get a kick out of that.  I’ve also seen urinals where the realistic image of a fly or a spider is etched/painted onto the urinal at the “sweet spot” where you get the least splashes.  Males apparently can’t resist trying to nail the bug to try to wash it down the drain.

“Visualized whirled pees?” responded one.

Other suggestions included:

You could change the school water supply to include small amounts of the super absorbent stuff (sodium acrylate?).

The simple remedy is to issue each boy a pair of vice grips set to clamp to a small circumference. This will restrict flow, encourage returning to class and giving new meaning toclamping down on a problem. (Raleigh McLemore)

I had hoped to avoid stepping into this subject out of fear it may be too deep for me.

Some things are too serious to joke about.

One of our more prolific contributors (Al Sefl) shared:

A classic book has been written about the trajectory of droplets caused by a liquid stream impinging on the urinal receptacle surfaces.  I believe The Bathroom by Alexander Kira was the first and most comprehensive study of both male and female urinals with backsplatter patterns.  It pointed out that most of the bathroom appliances were poorly designed and kept that way out of some misdirected sense of traditional design.  …  He came to the conclusion that the clear majority of receptacles were not scientifically designed to minimize splash droplets.  Other conclusions included were that the height of male urinals were often above the stream source so the end of the stream, as it peter’s out so to speak, often drops below the lower edge of the urinal.  The book was a text used in a course for one of my master’s degrees, Industrial Design.  It was very obvious that a complete redesign of the western lavatory in general was needed.

Al Self

Who thinks urinals should have a sign posted over them stating:



John September 27, 2009 at 10:32 pm

Yes, but did the fluorescing trick *work*!? And what was the source of the liquid? You can’t just offer up a mystery like that and not provide the answer!

sciencegeekgirl September 27, 2009 at 10:48 pm

I never did hear the outcome from the teacher who originated the question! Even without an answer, the mystery is… amusing, at worst.

Andrew B September 28, 2009 at 2:31 am

Science geek girl – I am your friend in a way, since you seem to enjoy the world around – but I want you to ponder what I’m about to say. What is the ‘grand significance’ of science.. if the history of life on earth shows that the current ecosystem is just a second away from an asteroid that would destroy life as we know it – and god forbid, egotistic reptiles go on to live while intellligent humans do not – why are u continuing to stress the importancec of scienece and parading around that you are this science woman? Since you “are a physicist” ill come clean with my bent – it’s the brain beehive, and your method of trying to educate students about science completely comes down to brain mechanisms involved in motivation learning and memory. So get this: … the one kink in the brain seems to be emotions on the persons face that gets off the mirror neurons of the people listening, somehow or other, along with verbal cues.. the sound of the voice, gestures, this may fling to life the nucleus accumbens in the listeners and through the miracle of nature, get them to go out and look into science – to actually learn it. Your succcess as a science comminicator – or even as a successful communicator of the importance of brushing twice a day (or how great socks are) comes down to getting this brain region active. It’s funny that almost no one realizes this, and all efforts to write books, attend conferences on pedagogy have no idea what teaching is nor how it works. This is incredibly funny if you stop and think about it. Imagine all of the libraries accross the united states now with students studying – perhaps 1 in every 2,000 has an inkling of what they’re doing when a book is put in front of their retina and they’re studying. They may take ritalin to help them concentrate, they don’t know what that does, but surprise – it makes the NaC more active indirectly, so by accident (just like the pill) it makes the activity more rewarding. etc.
Anyway, enough ranting – remember this. From now until you die, your ability to get their nucleus accumbens’ to sing will determine your succcess as a teacher of anything. It has nothing to do with knowing the information your trying to convey – anyone can go into barnes n noble and pick up a book on how to learn to be a triatholon runner or noble prize winning bird spotter – the difference is getting that pea sized group of cells to hum to life.. and it won’t work if you keep talking about the grand significance of science in terms of survival, nor if you try superficial means (like your blog) to get that across. By chance or mistake, the nervous system of your peers will only sing to life in this region if you yourself show those cues of genuine excitement and passion. If you don’t have it, you won’t be a successful science teacher. If you are passionate about a topic, and it’s not superficcial, use talks as an oppurtunity to convey that excitement, and you’ll be one of the best teachers ever.
Rosalind Franklin’s xray pictures were to the discovery of DNA what the study of reward circuity will be to an award winning teacher of anything (the content doesn’t matter – it’s the passion)
and no more talking about science.
do it – discover it. and i challenge u never to mention your a scientist to anyone, to keep it to yourself – that way you will please the gods and spare yourself of vanity.

Captain Skellett September 28, 2009 at 3:08 am

The tricky part would be ensuring that the surface was completely clean / devoid of urine before the mystery puddle appeared so as to avoid cross-contamination. It still wouldn’t help with intent – a ccv camera might help, but that’s probably a bad thing to have in school toilets, right?

The polymers are certainly beautiful, and this post is freaking hillarious – love the idea of a fake bug they try to spray off, but the roulette just sounds… splashy. Urinal reform for the win!

Michael Varney September 29, 2009 at 1:04 am

and no more talking about science.
do it – discover it. and i challenge u never to mention your a scientist to anyone, to keep it to yourself – that way you will please the gods and spare yourself of vanity.

I guess you would prefer to use anonymity to distance yourself from your rambling, fairly incoherent and poorly spelled grammatical nightmare?

How about rather than question sciencegeekgirl’s vanity in pointing out she is a physicist, you instead discuss the science behind her posts?

You, being of a “brain bent”, should be well aware the power of appealing to authority, or appealing to expertise when trying to convince someone of your ideas. Can you fault Stephanie for using this human tendency in her blog, which after all is an attempt to educate?

If you fault her, then you have to fault every single teacher who has used this very method in any introductory course they have taught. For how often must a teacher use their authority to forestall questions that can hinder learning (either the student asking or the others in the course) by using their authority?

How many universities promote the expertise of their faculty in asking for funding, or recruiting students?

All learners need a basic knowledge set in order to explore their interests. At some point early on one must submit to ideas presented as axioms. Later knowledge and critical thinking can lead one to question those axioms.

Some argue that appeal to authority is useless as a debating method, and as a teaching tool, and can be abused. One should then ask: Why is it that “appeal to authority” can be abused?
Perhaps because it works?

How about you use some of the knowledge you have acquired to satisfy your “brain bent” and discuss this on the blog?

I for one think that if Stephanie uses her authority as a method of convincing people of the validity of her ideas, and doing so succeeds in helping a student on the path to learning, then she should by all means go for it.
She just needs to make sure she can back up her claims when asked to do so beyond asserting herself as a scientist.

Since Stephanie is a physicist, I am sure she can handle that just fine.

Matt October 7, 2009 at 12:00 pm

For fun, someone could have poured a bottle of tonic water near the urinal. Tonic has quinine which will also glow under a UV light.

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