How many times have you heard this or asked yourself this, perhaps when entering a bath and finding it dirty: Why don’t men hit the toilet hole when they urinate? With the result of dirty of drops of pee there tablet of the toilet and maybe the same flooring next to the toilet. If you are male and you are reading these lines, you will partly have your own personal answers. The interesting thing is that the reasons therefore, when a man pees, he risks making a mess, are often independent of his degree of attention and his aim. In short, partly the science comes to our aid. On the other hand, it is obvious that we have no excuse when we don’t clean the bathroom after dirtying it.
Below you will find a list of some of the reasons why men miss the mark (or in any case dirty the toilet seat) when they go to pee (excluding particular pathologies). In general terms, we can summarize by saying that the stream of urine does not always go straight and there is no way to predict its precise direction. Furthermore, the sketches on the tablet can also derive from rebound of pee on the surface inside the toilet. Here she is list of 5 of the main causes:
1. Pressure: especially when the urge to urinate is intense, in the first seconds of urination the pressure of the pee coming out is very strong and therefore the direction of the jet is not so easy to predict. The same thing happens, in reverse, if the outlet pressure is too low. In this case the so-called Coandă effect can be generated, a fluid dynamic phenomenon due to the adhesion and cohesion forces of the fluids, such that the latter, when they are in motion (especially at low speed), tend to follow the surfaces with which they come into contact contact. In this case, the little pee that comes out initially follows part of the glans or foreskin and thus does not fall where one might have assumed. This phenomenon can also happen at the end of urination. This effect is why it is often difficult to pour liquid from one container to another without spilling some of it.
2. Rebound: depending on the shape of the toilet and the exact point of impact between the jet of urine and the inside of the toilet, be it ceramic or water, ricochet splashes are generated which can end up below or below above the toilet seat. The dynamics, in particular, was studied by a team of researchers from Splash Lab from Brigham Young University. In a nutshell, the answer is that you should stay as close to the toilet as possible, ideally sitting rather than standing, so that the jet does not “break” into multiple drops and generate larger splashes. If you want to remain standing and have excellent aim, you should prefer the ceramic walls instead of the water and, in case you hit the latter, you should try to produce a jet as perpendicular as possible, so as to produce fewer splashes. It’s the same concept as, for example, diving competitions. Below you can see a video of one of the experiments conducted by Brigham Young University.
3. Apical part of the urethra “closed”: it may happen that temporarily the internal walls of the final part of the urethra, i.e. the canal through which sperm and urine pass and exit (called the external urinary meatus) become totally or partially “sticky”. Depending on the type of contact, the initial passage of the urine can be hindered completely, increasing the pressure at the outlet of the jet, or partially, perhaps causing the pee to flow out only from one part of the orifice (increasing the pressure and modifying its direction) or from two different sides, resulting in a division of the jet. This temporary condition of adhesion can be caused by the presence of semen residues (resulting from a previous ejaculation or from normal very small daily losses). It is the same thing that happens, for example, to the small holes in the shower head, which are totally or partially blocked by limescale.
4. Erection: the condition of erection significantly modifies the shape and size of the urethra (however always variable even in resting conditions) and generates difficulty in predicting the direction of the urine jet. The presence of an erection, however, can easily be linked to the previous point, that of the adhesion of the internal walls of the external urinary meatus (perhaps due to the presence of traces of sperm). Not only that: if you urinate after ejaculating, the presence of residual sperm in the urethra can partially block it, resulting in a very unpredictable flow.
5. Low Lights: Low bathroom brightness or the sudden turning off of lights in bathrooms with automatic lighting can contribute to a person losing aim or decreasing accuracy when urinating. The same can be said if the lighting has not been well designed, the light source is located behind the back of the person in the bathroom and the light therefore projects the shadow of the person right onto the toilet.
