Men’s lack of precision when aiming into the toilet often results in splash-back, as any parent or janitor can attest. To reduce spray, designers have tried everything from fabric inserts to curiously shaped urinals.
Amsterdam’s Schiphol Airport used a physical design change to nudge men to aim better—and reduced spillage by 80%, saving them 8% on cleaning costs.
1. Urinal flies in Amsterdam
Men are notoriously careless with their aim when urinating, a fact that can cause a mess in public restrooms. For decades, urinal designers have tried to reduce splashback with everything from screens that let urine in but not out to rubber floor mats and curiously shaped urinals that make the stream ricochet off concave walls into rather than out of the bowl. But some of the most successful solutions—like the fly-engraved urinals at Amsterdam Schiphol Airport—relied on nothing more than human psychology and the knowledge that we perform better when we have a toilet target to aim for.
In the early 1990s, cleaning manager Aad Kieboom at Schiphol figured out that etching small photorealistic images of flies in all of the urinals right next to the drain would give people something to aim at, and it worked: urinal spillage dropped by 80%, which reduced the airport’s overall bathroom cleaning costs. Similar fly-embossed urinals have since popped up all over the world.
The flies, which are actually moth flies (Psychodidae) in the family Psychodidae, are common denizens of sanitary drains where their larvae feast on organic muck. The flies were selected because they are small and visible, and their presence is believed to remind people of the importance of careful aim—especially when peeing and standing up.
Aiming directly at a vertical wall of a urinal can create a nasty kickback, and aiming at the toilet water can also lead to splashback. But aiming slightly to the side and narrowing the angle of impact will significantly reduce both these problems.
The flies at Schiphol are etched in a specific pattern to mimic the flow curve of urination and the angle at which a man normally stands when voiding. Similarly, the urinal simulators at BYU use a series of images to mimic the nuances of the voiding process. By analyzing the flow of urine and the angle at which it hits, the researchers are able to determine how different images are most effective at reducing splashback. The resulting images are then used to train students at the school to use proper techniques in the stalls.
2. Urine simulators at BYU
Amid all the guff about men being boys that leads to toilet messes, physicists have been trying to nudge them into better aim. As reported in Science Daily, one trick was to paint a fly on the inside of urinals to encourage men to direct their stream at them rather than bouncing back onto walls and trousers. The BYU team’s method was a little more sophisticated, constructing a urine simulator in a water tank that tracked the impact of pee.
The researchers found that the best way to reduce splashback is to change the “angle of attack.” Standing up straight causes those pee droplets to hit the urinal wall at a 90-degree angle, creating huge amounts of splashback. But sitting down lowered the impact to a more modest level. It also helps to aim low (imagine hitting just above the urinal drain) as opposed to straight at the urinal.
To test this, the team filmed several different urinal designs and then simulated each using the urine simulator. Then they wiped up the splashes and weighed the towels to determine how much the various designs produced. The optimal design, the scientists report in Scientific Reports, looks like that nautilus shell. It drastically reduces splashback and the drops that do make it back as they head downwards into the urinal drain.
Medical students have been implicated in catheter-associated urinary tract infections, highlighting the need for hands-on training to promote a sterile technique. Simulation can help with this, as it allows learners to make mistakes in a safe environment and provides opportunities to gain confidence before performing the procedure.
A recent study looked at medical students undergoing urinary catheterization simulation and found that those who were taught the task by an interactive instructor with access to a high-fidelity human urinary catheter simulator performed significantly better on a retention test than those who were taught by an instructor in a lecture format without a simulator. The group that practiced on the simulator had a 4.3-fold increase in index examination scores compared to the instructor-only teaching groups, which had a 1.7-fold difference in their index exam score.
3. Sitzpinkler in Germany
In the US and the UK, sitting down to pee is a fairly recent development, but in Germany, it’s the norm. A man who prefers to stand up while urinating is known as a Stehpinkler, and in 2015 a court ruled in favor of one such man when his landlord sued him for claiming urine splashes damaged the marble bathroom floor.
A new device called Spuk (also known as WC-Geist or “toilet ghost”) was introduced in 2004 to help encourage men to take a seat. It can be placed under a toilet, and when a man lifts the seat to get a better aim at the bowl, it voices a message asking them to return the seat to its horizontal position and encouraging them to do their business while sitting down. For added authority, the warning can imitate the voice of Angela Merkel, Helmut Kohl, or other former German chancellors.
While men in the United States and Britain still largely prefer to stand up to pee, in Germany, more than two-thirds of the men surveyed by British market research firm YouGov said they always or most often sit down to do their business. That put them at number one among 13 countries surveyed, ahead of Canada, Australia, and Japan.
The reason for this difference is likely cultural, not biological. As YouGov explained, the German language is rich in single words that encapsulate concepts that require half a sentence or more to express in other languages. Thus, the term Sitzpinkler carries with it the implication of unmasculine wimpiness that may not be present in other cultures.
Whether you agree with this interpretation or not, the fact is that Germans are a very proficient population at Sitzpinkeln. A survey from 2021 showed that over 60% of the country’s men favored the seated position when peeing, beating out even the more macho Japanese at this particular macho pursuit. It might be time for the US to consider adopting a similar strategy. After all, if the American men who polled on the matter are any indication, standing up to pee isn’t nearly as macho as it seems.
4. Smart toilets
Many smart devices found throughout the home have been hailed as game-changers for their ability to streamline chores and automate tasks. The smart toilet is a new addition to this category, offering a variety of functions for the modern household.
The smart toilet aims to reduce the time it takes for people to finish their bathroom routines by automatically scanning and processing stool and urine for health-related information, such as hydration levels, diet imbalances, or signs of gastrointestinal diseases. It can also provide users with insights into their microbiome, a key factor in overall wellness and digestive health.
Joshua Coon, an academic who works on this project as part of his master’s degree, says he is still working to perfect the technology. He is primarily focused on urine, as it is easier to sample and analyze than stool, which is more difficult to collect in an accurate manner. He explains that a urine sample can contain up to 1,000 different small molecules that indicate the state of a person’s microbiome, hydration level, and more.
In order to collect physiological data, the smart toilet seat is connected to the user’s smartphone via Wi-Fi or Bluetooth connectivity. Each time a user sits on the toilet, the app sends an ecological momentary assessment (EMA) questionnaire to their mobile device that asks them about their mental well-being and gut health.
This EMA questionnaire is linked to the sensor data collected by the smart toilet. Coon explains that participants can decide whether or not to participate in the study. If they choose to do so, they are required to agree to the collection and storage of their data. Otherwise, they will not be able to use the smart toilet.
Respondents who participated in the study were largely positive about the smart toilet. Many cited the benefits of monitoring their health status and identifying early signs of disease, as well as the potential to lower medical expenses by identifying asymptomatic conditions such as urinary tract infections. However, one complaint was that the prototype was difficult to clean and tended to attract dust and grime. The researchers note that this reflects a general sentiment amongst participants that smart appliances must fit everyday practices and norms to be accepted.