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