10 Misconceptions About Things That Can Kill You

Sucking out a viper's venom won't save your life.
Sucking out a viper's venom won't save your life. / Cavan Images/iStock/Getty Images Plus

Ever been bitten by a venomous snake? Or gotten lost in the desert with an empty water bottle? Perhaps, at the moment of the greatest danger, your panicked brain called up some survival advice. You might have started sucking out that snake venom, or started looking for the nearest cactus to cut open for relief.

Eventually it would have dawned on you that these were not good ideas. And yet, countless people go through life believing in these misconceptions about things that can kill you. Let's look at a few of them, adapted from an episode of Misconceptions on Youtube.

1. Misconception: You sink in quicksand.

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 water. Even if someone struggles and flails 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. (Having a friend on dry land throw you a rope and pull you out should be Plan A, though.)

2. Misconception: Pulling a knife out of your body is better than leaving it in.

If you get impaled by any object—and we sincerely hope you don't—you should leave it in, then call 911. Dr. David Beiser, an emergency physician at the University of Chicago Medical Center, says, "It may be plugging a hole in an artery or vein, and as soon as you take it out, you could bleed to death."

3. Misconception: 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. But that will not really provide water—it's more like juicy cactus pulp. It also contains a lot of toxic alkaloids, which can make a person vomit or have diarrhea, which will only make them more dehydrated. So don't forget to take a gallon or so of water with you.

4. Misconception: if you're dehydrated, you can drink your own urine.

Many people have claimed that drinking their own urine has saved them in desperate situations. And it's true that this will work for a day or two, but 5 percent of urine is waste products that your kidneys are intentionally getting rid of, so as you continue to pee and drink, your urine will contain more and more waste products that are dangerous to drink. This will eventually cause kidney failure. Also, gross.

5. Misconception: An umbrella will slow a long fall.

In 2013, pro skier Erik Roner tried to skydive with just an umbrella (well, and a backup parachute). It may have slowed him down a little bit at first, but within a few seconds, the umbrella flipped inside out, making it completely useless.

6. Misconception: House fires are less common than fires in commercial and public buildings.

According to a survey conducted by the Society of Fire Protection Engineers, 65 percent 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 2500 deaths in the U.S. due to fires in homes. That same year, there were only about 100 deaths due to fires in non-residential buildings.

7. Misconception: Tornadoes don't happen in winter.

Tornadoes are possible any month or season. In fact, in 2008, there was a notable tornado outbreak on February 5 and 6 in the Midwest and South. Five states were affected over the course of about 15 hours: Missouri, Illinois, Arkansas, Alabama, and Tennessee. Tornadoes can actually be deadlier in the wintertime because they typically move faster.

8. Misconception: If you're stuck in a falling elevator, 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. You need to have a very impressive reaction time, and even then, you could only reduce the speed of your impact by about two to three miles per hour. 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 50 mph.

9. Misconception: Always play dead during a bear attack.

How to behave during a bear attack depends on 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 make loud noises. If you have pepper spray, you should use that. Just get out of there.

10. Misconception: You should suck the poison out of a snake bite to save your life.

"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," University of Maryland School of Medicine physician Robert A. Barish has said.