Hi, I'm Elliott, this is mental_floss on YouTube.  Today, I'm gonna talk about some misconceptions about deadly things and situations, so buckle up.  No, really.

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Misconception #1: You sink in quicksand.  As John Mulaney said, "I always thought quicksand was going to be a much bigger problem than it turned out to be."  A 2005 study published in the journal Nature found that people can't totally sink in quicksand.  We actually float in it, because we're not dense enough to sink in the mixture of sand, clay, and saltwater.  Even if someone struggles and wiggles like we're told not to do, the most a person will sink is probably waist deep.  At that point, if they just wait patiently for the quicksand to settle, they should be able to start floating out.

Misconception #2: Pulling out a knife is better than leaving it inside you.  If you get impaled by any object, and I sincerely hope you don't, you should leave it in, then call 911 or get to the emergency room.  Emergency medicine physician from the University of Chicago Medical Center, Dr. David Beiser has said, "It may be plugging a hole in an artery or vein, and as soon as you take it out, you could bleed to death." 

Misconception #3: If you run out of water in the desert, you can drink from a cactus.  People may tell you that if you're stranded and dehydrated in the desert, you should try to open a cactus for water.  First of all, that is not water, okay, it's more juicy cactus pulp, and second, that juicy cactus pulp contains a lot of toxic alkaloids, which can make a person vomit or have diarrhea, which will only make them more dehydrated.  So just, if you're out there, just good luck.

Which brings me to misconception #4: If you're dehydrated, you can drink your own urine.  Gross.  Many people have claimed that drinking their own urine has saved them in desperate situations.  Lookin' at you, Bear Grylls, okay?  And it's true that this will work for a day or two, but 5% of urine is waste products that your kidneys are intentionally getting rid of, so as you continue to pee and drink, just having a great time, partying or whatever, the urine will contain more and more waste products which are dangerous to drink.  This will eventually cause kidney failure.  Also, gross.

Misconception #5: An umbrella will slow a big fall.  It will not.  In fact, in 2013, pro-skier, Erik Roner tried to skydive with just an umbrella (well, and like, a backup parachute).  It may have slowed him down a little bit at first, but within a few seconds, the umbrella flipped up, making it completely useless.

Misconception #6: House fires are less likely than fires in commercial and public buildings.  According to a survey conducted by The Society of Fire Protection Engineers, 65% of Americans feel safer from fires at home compared to a commercial or public building.  But most deaths due to fire happen in the home.  In 2011, there were around 2,500 deaths in the US due to fires in the home.  That same year, there were only about 100 deaths due to fires in non-residential buildings. 

Misconception #7: There are no tornadoes in winter.  Not true!  Tornadoes are possible any month or season.  In fact, in 2008, there was a notable tornado outbreak on February 5 and 6th in the Southern United States.  Five states were affected over the course of about 15 hours: Missouri, Illinois, Arkansas, Alabama, and Tennessee, and actually, tornadoes can be even deadlier in the wintertime because they typically move faster.  That was my--me doing a tornado.  My mini tornado.  You're welcome.

Misconception #8: If an elevator is falling, jumping will save your life.  People say that if you're caught in a falling elevator, jumping at the exact moment of impact might save you, but this doesn't really work, okay? You need to have a very impressive reaction time, and even still, you could only reduce the speed of your impact by about 2-3mph.  You'd also need to jump faster than the elevator was falling, which would be pretty tough, considering falling elevators tend to hit the ground at about 50mph.

Misconception #9: Always play dead during a bear attack.  According to experts, how to act during a bear attack depends whether the bear is being predatory or defensive.  Grizzly bears tend to attack when they're being defensive.  In those cases, it's best to play dead, because that shows the bear you're not a threat.  Black bears are usually attacking in a predatory way.  In this case, playing dead doesn't do much.  If you have food, drop it, and back away slowly.  If the bear keeps coming, you should get aggressive, scream and be loud.  If you have pepper spray, you should use that.  Just get out of there.

Misconception #10: Suck the poison out of a snake bite to save your life.  Emergency room physician at the University of Maryland School of Medicine Robert A. Barish has claimed, "The evidence suggests that cutting and sucking, or applying a tourniquet or ice does nothing to help the victim.  Although these outdated measures are still widely accepted by the general public, they may do more harm than good by delaying prompt medical care, contaminating the wound, or by damaging nerves and blood vessels."

Thank you for watching Misconceptions on mental_floss on YouTube.  If you have a topic for an upcoming Misconceptions episode that you would like to see, leave it down in the comments and we'll go through it and we'll inform you of all the misconceptions about it.  It'll be awesome.  I'll see you next week.  Bye. 

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