According to Hollywood:
It is one of the most common murder methods in Hollywood.
The unsuspecting victim is soaking in a bathtub, while we get a POV shot of two hands holding a radio or a toaster. The victim looks up just in time to see their attacker, then the electrical appliance of doom is tossed into the water. Cut to the rest of the cast, wondering why the lights have flickered, then back to our victim, now dead and smoking.
It toasts bread and vulnerable coeds.
If you're not familiar with how electricity works, let's briefly go over it. Electricity is just a flow of electrons from some place that has too many of them to some place that really wants them. But where they really want to go is to the ground. If generated power is a shipload of sailors on shore leave, the ground is a whore house that's having a two-for-one special.
The light switch is ... a dental dam?
So those horny electrons are going to make a beeline for the ground, and totally ignore anything that doesn't get them there as quickly as they can. This is why a welder could put his hand on a piece of metal that he's zapping hundreds of amps of current through, because the metal is connected to the ground with a big clamp. Compared to the air (which sucks at conducting electricity), the welder's juicy 80 percent water body might seems like a good road to Miss Kitty's House of Ground, but there's a convenient superhighway running through that clamp and electricity will always take the path of least resistance.
So going back to our bathtub, the person sitting in the tub doesn't offer any kind of decent path to ground. In older houses, the drain will provide a nice path (all that copper pipe), and in newer houses with PVC pipe, there may not be a path at all. Not to mention that if you plunge a radio into a bathtub, the first thing that's going to happen is that the water will short out the circuit and trip the circuit breaker.
Depending on the proximity of Rihanna's most recent release, that might be a mercy.
Don't get us wrong -- it is totally possible for electricity to ruin your day in the bathroom. If you're holding a hair dryer and you're soaking wet, your body may very well be the best path from the dryer to ground. And along the way, the current is likely to make a rest stop at your heart, and not pick up the trash when it's done.
But you're still more likely to slip and crack your head on the porcelain.
This is why, if you are in a newer house, your bathroom outlets have little black and red buttons on them. They're supposed to trip and shut off the current if some dumbass tries to dry his mullet in mid-shower.
According to Hollywood:
Drop a cigarette into a pool of gas leading to the car with the bad guys in it, and you're just seconds away from an explosion. Or light the trail of fuel left by a leaking jet on take-off, and watch it turn into a nice fireball (we're looking at you, Die Hard II).
Obviously gasoline is really good at burning, that's why it makes a good fuel. But getting it to explode takes real effort. That's also why it makes a good fuel. You don't want every stray spark doing a Michael Bay on your gas station.
To that end, liquid gasoline doesn't explode at all -- you can drop lit matches into a bucket of gasoline in cold weather, and the match will probably just go out. (NOTE: We said PROBABLY.)
So smoking at the gas pump? Totally safe.
It's the vapor you have to worry about -- those tiny particles swirling in the air are what is catching fire when you throw a match onto a pool of gas. But to get an honest-to-goodness explosion takes a lot of vapor mixed with oxygen, and only in the right amounts. You can get it in tanks with just a little gas left in them, but as the Mythbusters have demonstrated on numerous occasions, you can do just about anything to a car and it won't explode.
Now, if you get a car burning, the fuel tank will eventually burst, and then maybe you'll get a nice fireball as all the gas combusts. But more often than not the fire will just burn steadily until all of the fuel is gone.
You're no fun anymore, gasoline.
Jet planes are even less likely to go Boom. Turbine (jet) powered aircraft use Jet-A, which is an aviation fuel that has a flash point of 100F. So certainly on that snowy day in Washington, John McClane wasn't going to have much in the way of fumes to ignite. Yes, transportation safety guidelines ruin yet another action movie premise. We're wondering if it's all really worth it.
For more things movies got wrong, check out 5 Ridiculous Gun Myths Everyone Believes (Thanks to Movies) and 8 Scenes That Prove Hollywood Doesn't Get Technology.