5 Dangers That Movies Are Lying to You About

5 Yellowstone’s Overdue Eruption

You’ve Heard: Volcanos are scary, but supervolcanos are superscary, and we happen to have one roughly in the middle of America. It’s called the Yellowstone Caldera, it spans thousands of square miles and when it decides to blow, that’s the end of us all. The eruption will practically blast the continent apart, ands the worst thing about it is it could come any day now. In fact, it likely will come any day now. We’re long overdue for an eruption at Yellowstone, so the chance of the big one hitting increases with each passing hour.

Below, you can see how the eruption looked in the 2009 movie 2012 (not to be confused with the 2012 movie 2009). Of course, this was a wacky disaster movie, and the way that vehicle shrugs off lava meteors tells you not to take this seriously. But they based this scene on the real well-known concept of Yellowstone’s overdue eruption, and the real eruption will be unfathomably bigger than the one depicted here. 

But in Reality: We’ve known about that giant caldera and its history of eruptions for a long time. But in the 21^st century, armed with scientific doodads and the most sophisticated of thingamajigs, scientists found out what the situation really is like down there. They sent waves under Yellowstone and measured how they bounced back, and it turns out that there simply is not enough magma down there for some big eruption in the foreseeable future. Plenty of the rock down there is hot but solid (rock solid, you might say). Meanwhile, even the parts that are molten are not very molten.  

As for that old idea that an eruption is “overdue,” it turns out volcanos don’t work that way. We take that image from earthquakes, which we all know a little too much about because they’re common in California. Earthquakes can be overdue because the plates of the Earth move constantly, and if quakes don’t release the stress, the stress builds. With volcanos? Magma doesn’t continuously build up and might never build up. 

Sure, Yellowstone last erupted 631,000 years ago, and previously erupted another 669,000 years before that. But if that were a set schedule, it would be another 38,000 years before it erupts — and it’s not a set schedule. We checked and didn’t find 600 millennia of magma waiting to burst from down there. 

So, go vacation in Yellowstone, and relax. So long as you don’t fall into a boiling acid pool or get trampled by a buffalo, you’ll be fine. 

4 The Bite of a Tarantula

You’ve Heard: Spiders terrify many people, and the tarantula offers a special additional fear. While the furriness of the spider should make it look cute, something about it tells you that this critter packs an extra deadly bite. When a tarantula crawls on your face, it’s time to scream. 

But in Reality: No one has ever died from a tarantula’s venom. A few people do die every year from other kinds of spiders bites, but not the tarantula, whose bite is around as venomous a single bee’s. Even comparing it to a bee oversells the danger, as bees kill dozens of allergic people every year, while (we’ll say it again) tarantula venom has never killed anyone.

Those hairs on the tarantula? Those actually are more likely to hurt you than the venom, since they’re spiky and might get in your eye. Even so, those have never killed anyone either, so don’t worry too much about them. 

More than anything else, though, to convince you not to fear tarantulas, here’s a video of tarantulas with their pet frogs:

In the Amazon, the burrowing tarantula keeps a dotted humming frog as a pet. The frog eats ants around the spider’s eggs, keeping them healthy, and the tarantula protects the frog from large predators, such as snakes. 

So, the tarantula is a cooperative creature, and you need not fear it. Unless you threaten its frog friend, of course, in which case it will find some way to murder you, possibly with a shotgun.  

4 The Touch of a Leper

You’ve Heard: Beware the touch of the leper because it can turn you into a zombie. Leprosy will jump to your skin and eat into your flesh, until your fingers and toes fall off. Or, as in the movie It, a leper might turn out to be a demonic clown in disguise, which is arguably worse. 

For a slightly more serious look at the threat of leprosy, consider historical leper colonies. People feared contact with the afflicted so much that they confined lepers to isolated communities. In the Philippines, lepers went to an island called the Island of Living Dead. Perhaps you saw lepers ostracized and suffering in the movie Ben-Hur, where the lepers were only healed through the death of Jesus, which you may be unable to schedule again when you need it. 

But in Reality: Leprosy is a bacterial infection. It does not eat away at your fingers — lepers did historically lose fingers and toes simply because their skin grew numb, so they didn’t notice when they got injured. But if you happen to catch leprosy, you really needn’t worry. We have a cure for leprosy: antibiotics. Yeah, medicine is great sometimes. 

So, having leprosy isn’t so terrifying. But also, you don’t really need to fear catching leprosy if you meet a leper. It’s not a very contagious disease. Though it changes the appearance of skin, it doesn’t transmit easily through skin-to-skin contact. You can live with a leper just fine. You can shake hands or even have sex with a leper without being in danger of catching the sickness. And that’s if it’s even possible for you to ever catch the sickness, because for most people, it’s not. Some 95 percent of people are naturally immune to leprosy. 

Since the word “leprosy” conjures up so many scary images, we now sometimes prefer to call it Hansen's disease, after the doctor who discovered the germ behind it. Unfortunately, that name just makes it sound like an even worse type of touch that you want to avoid, thanks to Chris Hansen and To Catch a Predator.

2 Contagious Poison Ivy

You’ve Heard: While we’re on the subject of stuff spreading on your skin, let’s talk about poison ivy. It’ll give you a nasty rash, and if you’ve never experienced it firsthand, you’ll still know it well from seeing many a TV character reach for some leaves as toilet paper, only to soon learn the awful truth about what they’ve done. Cut to them itching all over, followed perhaps by them taking a bath in soothing oatmeal.

Of course, you mustn’t touch someone who's afflicted with poison ivy, else it may spread to you. And if you have it, don’t scratch it, else that will spread the rash to previously healthy skin. 

But in Reality: Once again, just because a condition is visible on the skin doesn’t mean touching that skin will transmit it to you. When someone has a rash from poison ivy (officially known as urushiol-induced contact dermatitis), that rash doesn’t ooze with poison. Touching it will not spread the poison to you, and scratching it will not spread the poison elsewhere. The rash probably will spring up in new patches of the sufferer’s skin, and they probably will scratch themselves, but those two events are unrelated. 

In fact, poison ivy doesn’t involve poison at all. It involves a substance called urushiol, which is not poisonous but which is allergenic. Your skin getting all blotchy is just your own immune system panicking because you’re experiencing an allergic reaction. 

Most people are allergic to urushiol, but not everyone is. You may well be part of the quarter of the population who aren’t, which means no amount of poison ivy will have any effect on you. To find out if you’re in the lucky 25 percent, go rub your face in some today.

1 Air in Your Blood

You’ve Heard: Now, let’s go from ivy to I.V. An intravenous line is a fine way to introduce all kinds of helpful substances into your system. It’s also a way to introduce several kinds of deadly substances into your system. Most surprisingly, it can be a way of introducing seemingly innocuous substances that then turn out to be deadly. 

An air bubble in your blood can create an embolism, blocking circulation to your lungs and killing you. For that reason, stealthy assassins in movies try injecting a simple bit of air into a victim’s I.V. bag. This bubble will soon glide through your blood, and you will choke on air, most ironically.

But in Reality: An embolism can kill you — that much is true. But a bubble floating in that bag does equate to a bubble in your pulmonary artery. It takes a whole lot of air in an I.V. bag to create a bubble of air in your blood. 

If you see a bubble floating around in your bag, it might look scary to you, but at 0.2 milliliters, it’s will have no effect on your body at all. A hundred times that, and that might give you symptoms. That’s more than a single bubble and might take an entire syringe, or two syringes. To kill you? There should be over 150 ml of air in the tubing for that, which would mean injecting your bag with eight or fifteen syringes of air. 

So, if you see an errant bubble in your own bag, don’t fret. And if you plan on killing a hospital patient, a pillow over the face works fine, and is far more thrilling. 

Follow Ryan Menezes on Twitter for more stuff no one should see.