Speaker 1: Welcome to brain stuff from how stuff works. Hey, everybody,
Speaker 1: it's me Christian Sager. Now today's question is why is
Speaker 1: it so painful to bite into aluminum foil? And if
Speaker 1: you're from across the pond, you may be wondering right now,
Speaker 1: why is he saying aluminium instead of aluminium? Well, I'm American,
Speaker 1: That's how I pronounced it all my life. I apologize.
Speaker 1: We're gonna go forward with aluminum. But it's a good question, right.
Speaker 1: So first things first, it's actually not painful for everybody
Speaker 1: to bite into this foil. It's painful for people who
Speaker 1: have fillings or crowns made of metal. You probably already
Speaker 1: knew that part, So let's fast forward. What is actually
Speaker 1: happening here. It's sort of like making a battery. So
Speaker 1: how does this happen exactly? Well, first, it's two different metals,
Speaker 1: the aluminum foil and the metal in your filling or crown.
Speaker 1: They have what's called an electrochemical potential difference, and they
Speaker 1: create the sort of voltage in the environment in your mouth,
Speaker 1: which is moist and salty. It's produced by your saliva.
Speaker 1: It's perfect for these two things to come into contact
Speaker 1: this way and to transmit energy. The electrical stimulation from
Speaker 1: this bootleg battery you have created is hitting the nerve
Speaker 1: in your tooth, and that is producing that weird, unique pain.
Speaker 1: The production of this current between the contact of two
Speaker 1: dissimilar metals. It's actually a pretty old concept. It's called
Speaker 1: the voltaic effect. It's named after a guy named Alessandro Volta,
Speaker 1: who most people credit with discovering this. In fact, if
Speaker 1: you want to learn more about this, on my other podcast,
Speaker 1: Stuff to Blow Your Mind, we went really far into
Speaker 1: voltaic batteries in an episode we did on Frankenstein. Now
Speaker 1: Volta he was making extra batteries a long time ago,
Speaker 1: and what he did was he stacked these dissimilar metals
Speaker 1: together and in between them he would put water her
Speaker 1: paper soaked with salt water. And he found that by
Speaker 1: doing this he could create a very low power battery.
Speaker 1: So that's essentially it. That's what's happening when you open
Speaker 1: a candy bar and you bite down on a piece
Speaker 1: of chocolate that still has a little bit of foil
Speaker 1: in it and you freak out because it's painful. You're
Speaker 1: essentially creating a battery in your mouth. Check out the
Speaker 1: Brainstuff channel on YouTube, and for more on this and
Speaker 1: thousands of other topics, visit how stuff works dot com.