Does Pushing the Button at a Crosswalk Actually Do Anything?

Pressing this crosswalk button may or may not do something.
Pressing this crosswalk button may or may not do something.
David Tran/iStock via Getty Images

Since crosswalk signals rarely seem to give you the green light (or more accurately, the white, human-shaped light) right after you press the button, you may find yourself wondering if those buttons actually work. The potentially exasperating answer is this: It depends.

First and foremost, it’s important to understand that crosswalk buttons aren’t designed to have an immediate effect; they’re just supposed to tell the system that a person is waiting to cross. As CityLab explained, some systems won’t ever give pedestrians the crossing signal unless someone has pressed the button, while others are programmed to shorten the wait time for walkers when the button has been pressed. No matter what, the system still has to cycle through its other phases to give cars enough time to pass through the intersection, so you’ll probably still have to stand there for a moment.

During busy traffic times or under other extenuating circumstances, however, cities can switch the system to what’s known as “recall mode,” when pedestrian crossings are part of the cycle already and pressing the button quite literally changes nothing. Unfortunately, there’s no way to tell if a particular button is in recall mode, short of calling your city officials and asking an expert to come inspect it.

But if you feel like a button isn’t doing anything, there’s a pretty good chance it’s been permanently deactivated. As congestion has increased and the systems to manage it have become more advanced over the years, cities have moved away from using crosswalk buttons at all. In 2018, for example, CNN reported that only around 100 of New York City’s 1000 buttons were still functioning. Since actually removing the buttons from crosswalks would be a costly endeavor, cities have opted to leave them intact, just waiting to be pummeled by impatient pedestrians who don’t know any better.

What about 'close door' buttons on elevators, you ask? That depends, too.

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Why Are Sloths So Slow?

Sloths have little problem holding still for nature photographers.
Sloths have little problem holding still for nature photographers.
Geoview/iStock via Getty Images

When it comes to physical activity, few animals have as maligned a reputation as the sloth. The six sloth species, which call Brazil and Panama home, move with no urgency, having seemingly adapted to an existence that allows for a life lived in slow motion. But what makes sloths so sedate? And what horrible, poop-related price must they pay in order to maintain life in the slow lane?

According to HowStuffWorks, the sloth’s limited movements are primarily the result of their diet. Residing mainly in the canopy vines of Central and South American forests, sloths dine out on leaves, fruits, and buds. With virtually no fat or protein, sloths conserve energy by taking a leisurely approach to life. On average, a sloth will climb or travel roughly 125 feet per day. On land, it takes them roughly one minute to move just one foot.

A sloth’s digestive system matches their locomotion. After munching leaves using their lips—they have no incisors—it can take up to a month for their meals to be fully digested. And a sloth's metabolic rate is 40 to 45 percent slower than most mammals' to help compensate for their low caloric intake. With so little fuel to burn, a sloth makes the most of it.

Deliberate movement shouldn’t be confused for weakness, however. Sloths can hang from branches for hours, showing off some impressive stamina. And because they spend most of their time high up in trees, they have no need for rapid movement to evade predators.

There is, however, one major downside to the sloth's leisurely lifestyle. Owing to their meager diet, they typically only have to poop once per week. Like going in a public bathroom, this can be a stressful event, as it means going to the ground and risking detection by predators—which puts their lives on the line. Worse, that slow bowel motility means they’re trying to push out nearly one-third of their body weight in feces at a time. It's something to consider the next time you feel envious of their chill lifestyle.

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Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

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

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