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Hi I'm Erin McCarthy, editor in chief of MentalFloss.com
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Welcome to Mental Floss Video, and did you know that we know more about galaxies thousands
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of light years away than we do about some of the things we experience every single day
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Like why intense emotions cause us to cry, for example. The tears we shed when we're emotional are chemically different than the tears that occur
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when something is in your eye, and scientists don't know if there's an evolutionary reason
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for those emotional tears. We know that babies cry to communicate and get attention, so some experts believe that
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adults might also cry for social reasons like to bond or to warn others that something's amiss
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But ultimately, why we weep when we're really sad, or really happy, or just really in our
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feelings is a mystery. And that's just the first of many surprisingly common things that science still hasn't figured
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out that I'm going to share with you today
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Like crying, we also don't know why people evolved the ability to laugh
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But experts guess it has something to do with communication, and not just that we find something funny
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One researcher found that only 20% of laughs he looked at were preceded by anything deemed
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in any way humorous. Maybe we laugh to let other people know that we're okay, or to bond with each other
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A study published in 2016 gave evidence for the latter. Researchers found that an outside observer could distinguish whether laughter was produced
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between a pair of strangers or a pair of friends. If you think about it, blushing doesn't make much sense
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often telling our fellow humans things we do not want them to know, like the fact that
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we've done something wrong or embarrassing. Some experts believe that we may have evolved
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blushing to show submission to group leaders. Others think it might have something to do
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with the fact that blushing people have been shown to be considered more likable, so it
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helps peers look past the bad things we done General anesthesia has been in use in the United States since 1846 but there are still some uncertainties about why the chemicals in anesthetics cause people to pass out
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A recent study showed that the drugs affect proteins in the brain, and the reason we go
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unconscious has to do with altering neural activity, but more research is needed
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And that brings me to consciousness, which is frequently defined as how we feel present
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and alive in the world. But the question is, why and how do we feel conscious
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It's of interest in both philosophy and science. Scientists would like to know which part of the brain is responsible for consciousness
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but it's still a mystery. Going back to drugs. We don't 100% understand how pain relievers containing acetaminophen give us pain relief
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We do know that acetaminophen's aren't totally consistent, they're more effective in some types of cells than in others
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So for now, scientists believe that drugs might be a specific type of enzyme inhibitor
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Scientists don't know what causes hiccups, what purpose they serve, or how to cure them
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something you might have figured out already from previous frantic Google searches
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A lot of people have favorite techniques, from gargling water to pulling hard on the tongue, but there's no scientifically proven way to get rid of them
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In 2002, one researcher tried to get to the bottom of the problem by looking at how 54
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hospital patients have been treated for hiccups. They tried multiple treatments, like holding their breath and medication, but none were
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proven effective. Moving on to a weather-related phenomenon. We don't know why only some thunderstorms create
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tornadoes and others don't. Generally, it's understood that tornadoes come to be when cold
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dry air interacts with warm, humid air. But those thunderstorms that result from those air
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conditions only sometimes cause tornadoes. It's also unclear why tornadoes die, though some experts
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believe that at least sometimes it has to do with the tornado's interaction with cold temperatures
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Maybe those tornado scientists would be able to figure it out if they never had to sleep but unfortunately they do And as you may have guessed we don know why I mean not just why tornado scientists need to sleep why we all need to sleep There are theories like maybe our ancestors slept
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because it kept them out of danger during the dark, dangerous nights, or it could be an energy
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conserving function. What we do know is that sleep helps us recover from the day, and there's
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evidence it changes the connections in our brains. Similarly, there are no clear answers as to why
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we dream. Some sleep experts think dreaming doesn't have a purpose at all. Others have theories like
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that we're playing out threatening situations, like being chased, so that we're better equipped
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to handle danger when we're awake. We often understand why we itch. There are diseases and
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bug bites and dry skin. But we don't totally know why we have the urge to scratch an itch
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We know that the body has receptors just for itches that are almost identical to those that
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convey pain, and it's thought that scratching might interfere with those signals. But at the
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same time, it might cause the skin to get more irritated, causing even more itching
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Scientists know some things about why we age, but no one has fully figured it out. There's
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little evidence for popular hypotheses having to do with things like free radicals and telomeres
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Aging is probably the result of a complex group of poorly understood processes
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meaning a cure isn't happening anytime soon. Another baffling thing about the natural world
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Why do some bird species migrate and the rest don't? The ones that do migrate might do it to
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conserve energy which might be kind of confusing since they're flying great
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distances and therefore expending a lot of energy to get to their destination
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But it's likely worth it since they're probably traveling somewhere with abundant energy sources, aka plenty of food
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Luckily, thanks to technology like tracking devices, scientists are able to track birds way more easily and are now learning much
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more about migration. Speaking of nature the question of nature versus nurture hasn been settled yet Technically we know that our genes interact with our environment to foster characteristics The question that science can figure out is to what extent A complicating factor is that it varies by
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trait and individual person. How much your genes are influencing your IQ, for instance
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may be different from someone else. The placebo effect is pretty mysterious. It's been proven again and again that sugar pills
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and other fake treatments can actually make someone feel better. And it's not just a
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healing. Brain scans show that placebos affect the area of the brain associated with pain
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and we still don't know why. It's believed that placebos somehow help release endorphins
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but experts need more information. Have you ever given a bike with no one on it a push and noticed that it stays up on
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its own? It doesn't fall over for much longer than you'd expect, and we don't know how
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it manages to balance itself while moving. And another mystery of physics. How do skates work on ice? There is a popular theory. We
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We know that ice has a very thin layer of liquid on it. So a skate moving quickly on top of ice might make more liquid because the friction causes melting
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The skate is actually changing the ice itself, creating a path on which to glide. Finally, it would be really nice to have a cure for the cold, but science hasn't managed
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to create one yet. We get colds from 7 separate families of viruses, and those families have subviruses
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So to cure the cold, there would need to be a cure that acts as a catch-all for about 200 subviruses
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And we just haven't figured out how to do that yet. Thanks for watching Mental Floss Video which is made with the help of all these nice people
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By the way, I'll be taking you over as host of this channel and I'm really excited to bring you videos full of facts that will make you feel smarter
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So don't forget to subscribe below and we'll see you next time
