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Why Does the Sound of Running Water Make You Have to Pee?

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Reader Bill wrote in to ask, “Why does the sound of running water make me want to pee—and sometimes badly?”

The quirk behind the burning need to pee when we hear rainstorms, waterfalls and babbling brooks seems to be all tied up in the power of suggestion.

Most of you are familiar with the name Pavlov, and know that he had something to do with dogs. That something is an experiment where the Russian doctor showed that autonomic responses (visceral reflexes that occur automatically and unconsciously under the control of the autonomic nervous system) could be triggered by outside stimuli.

Dog owners will attest that when a pooch gets its mouth on a piece of meat, they usually produce a river of saliva. In his experiment, Pavlov give dogs some meat powder, which caused them to salivate, right after ringing a bell. After months of repetition, he was able to ring the bell without any meat powder in sight, and the dogs would salivate because they’d been conditioned to associate the bell with food. For another example of classical conditioning in action, see this clip from The Office.

Pavlov thought that a lot of this automatic and unconscious learning happens all the time to people, and you can probably think of a few cases from your own life where you reflexively react a certain way to a seemingly unrelated stimulus. Having to pee at the sound of running water appears to be the same sort of conditioned response. The sound of running water not only mimics the sound of urination itself to create a Pavlovian association, but flushing and washing one's hands also produce that same sound and are closely associated with urinating and further strengthen the connection.

The catch is that this is just hypothetical right now. While many urologists and psychologists think that this is what’s happening, and have said as much in venues like The New England Journal of Medicine, there hasn’t been to my knowledge any published, peer-reviewed research on the underlying reason for the water-pee connection. There’s no denying that it’s there for a lot of people, though, even if we haven’t quite worked out the cause for it.

Plenty of nursing and psychology texts and parenting books advise running water in the sink for situations as varied as potty-training toddlers, helping people with paruresis (shy bladder), and patients fresh out of prostate surgery, who all may have trouble getting the waterworks started unassisted. In the early 1970s, one hospital in New York even gave select patients a tape recorder with headphones and a 30-minute tape of water sounds to ease their bathroom experience. The “audio catheter,” as it was dubbed, made a real splash with the patients and was a huge success.

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Big Questions
Where Is the Hottest Place on Earth?
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The summer of 2017 will go down as an endurance test of sorts for the people of Phoenix, Arizona. The National Weather Service issued an extreme heat warning, and planes were grounded as a result of temperatures exceeding 120 degrees. (Heat affects air density, which in turn affects a plane’s lift.)

Despite those dire measures, Phoenix is not the hottest place on Earth. And it’s not even close.

That dubious honor was bestowed on the Lut Desert in Iran in 2005, when land temperatures were recorded at a staggering 159.3 degrees Fahrenheit. The remote area was off the grid—literally—for many years until satellites began to measure temperatures in areas that were either not well trafficked on foot or not measured with the proper instruments. Lut also measured record temperatures in 2004, 2006, 2007, and 2009.

Before satellites registered Lut as a contender, one of the hottest areas on Earth was thought to be El Azizia, Libya, where a 1922 measurement of 136 degrees stood as a record for decades. (Winds blowing from the nearby Sahara Desert contributed to the oppressive heat.)

While the World Meteorological Organization (WMO) acknowledged this reading as the hottest on record for years, they later declared that instrumentation problems and other concerns led to new doubts about the accuracy.

Naturally, declaring the hottest place on Earth might be about more than just a single isolated reading. If it’s consistency we’re after, then the appropriately-named Death Valley in California, where temperatures are consistently 90 degrees or above for roughly half the year and at least 100 degrees for 140 days annually, has to be a contender. A blistering temperature of 134 degrees was recorded there in 1913.

Both Death Valley and Libya were measured using air temperature readings, while Lut was taken from a land reading, making all three pretty valid contenders. These are not urban areas, and paving the hottest place on Earth with sidewalks would be a very, very bad idea. Temperatures as low as 95 degrees can cause blacktop and pavement to reach skin-scorching temperatures of 141 degrees.

There are always additional factors to consider beyond a temperature number, however. In 2015, Bandar Mahshahr in Iran recorded temperatures of 115 degrees but a heat index—what it feels like outside when accounting for significant humidity—of an astounding 163 degrees. That thought might be one of the few things able to cool Phoenix residents off.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Big Questions
How Does Autopilot Work on an Airplane?
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How does autopilot work on an airplane?

Joe Shelton:

David Micklewhyte’s answer is a good one. There are essentially a few types of features that different autopilots have. Some autopilots only have some of these features, while the more powerful autopilots do it all.

  • Heading Hold: There’s a small indicator that the pilot can set on the desired heading and the airplane will fly that heading. This feature doesn’t take the need for wind correction to desired routing into account; that’s left to the pilot.
  • Heading and Navigation: In addition to holding a heading, this version will take an electronic navigation input (e.g. GPS or VOR) and will follow (fly) that navigation reference. It’s sort of like an automated car in that it follows the navigator’s input and the pilot monitors.
  • Altitude Hold: Again, in addition to the above, a desired altitude can be set and the aircraft will fly at that altitude. Some autopilots have the capability for the pilot to select a desired altitude and a climb or descent rate and the aircraft will automatically climb or descend to that altitude and then hold the altitude.
  • Instrument Approaches: Autopilots with this capability will fly preprogrammed instrument approaches to the point where the pilot either takes control and lands or has the autopilot execute a missed approach.

The autopilot is a powerful computer that takes input from either the pilot or a navigation device and essentially does what it is told to do. GPS navigators, for example, can have a full flight plan entered from departure to destination, and the autopilot will follow the navigator’s guidance.

These are the majority of the controls on the autopilot installed in my airplane:

HDG Knob = Heading knob (Used to set the desired heading)

AP = Autopilot (Pressing this turns the autopilot on)

FD = Flight Director (A form of navigational display that the pilot uses)

HDG = Heading (Tells the autopilot to fly the heading set by the Heading Knob)

NAV = Tells the autopilot to follow the input from the selected navigator

APR = Tells the autopilot to fly the chosen approach

ALT = Tells the autopilot to manage the altitude, controlled by the following:

VS = Vertical Speed (Tells the autopilot to climb or descend at the chosen rate)

Nose UP / Nose DN = Sets the climb/descent rate in feet per minute

FLC = Flight Level Change (An easy manual way to set the autopilot)

ALT Knob = Used to enter the desired altitude

This post originally appeared on Quora. Click here to view.

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