How Exactly does Acid Eat through Stuff?

Added: 2026-05-06

[00:00:00]Now, one of my favorite movies of all time is actually the movie Alien and the sequel Aliens. And in that movie, when the alien bleeds, it drips onto the metal decking of the spaceship and then it immediately eats through the decking going through several decks of the spaceship. So, my question to you is, what exactly is an acid? And why does it actually eat through stuff anyway? Now, basically acids or substances when they're in a water solution, they donate what we call hydrogen ions, right? So, you may have heard of the pH scale. PH actually stands for power of hydrogen.

[00:00:39]I'm going to explain why in a minute, but the more hydrogen ions that you have floating around in a water solution, the more powerful or the stronger the acid is. So on the pH scale, something that is neutral, neither acidic nor basic, the opposite of an acid, has a pH of seven. And as you go to the left to lower and lower numbers, you get to stronger and stronger acids with more and more hydrogen ions in solution. And as you go the other way, you get to something called more alkaline or more basic. Basically, the chemicals on this side don't donate hydrogen ions. They like to react with or accept hydrogen ions in solution. So acids and bases are basically uh opposites of each other.

[00:01:22]Now this is the most famous acid. It's hydrochloric acid HCl. This is actually what's in your stomach breaking down your food. So when this stuff goes into water, the hydrogen pops off as a hydrogen ion. And then you have the chlorine ions as well. The hydrogen ions, the more of them is what makes the acid stronger. Another very common acid's called nitric acid. Notice the formula HNO3. This hydrogen pops off as an ion, making it acidic. Finally, another really common acid is called sulfuric acid, H2S04. Notice there's two hydrogens's in this one, but again, it's the hydrogens that's making it acidic.

[00:01:59]The more hydrogen ions you have, the stronger the acid you have. Now, hydrogen's element one with one proton and one electron. So, when I say hydrogen ion, I mean simply a hydrogen without the electron. That means a proton, a naked proton is exactly the same thing as a hydrogen ion. So basically acids are substances that donate protons. Naked protons in solution. And if you remember, gravity is actually the weakest force in the universe. The electric force is millions of times stronger. So naked protons floating around solution can attract electrons really, really powerfully and strongly. So they can rip the electrons off of metal. They can rip them out of your flesh. They can rip it out of the decking. And that's why they react so much and dissolve stuff like in the movies. Learn anything at math and science.com.