Subtitles section Play video Print subtitles I am still in the Arctic, so today's guest video comes from Chase at ScienceC, who sent in the best pitch out of all the 150 that I got. And it started, “hi Tom, I've got two of my sister's teeth dissolving in soda”. I have a confession to make. I love Mountain Dew. I think my weather balloon video alone probably took a few 12-packs. Mountain Dew isn't exactly known to be the healthiest beverage out there. So today, I'm going to do a little experiment to see just how bad Mountain Dew is for your teeth. So right here, I have two of my sister's molars. I'm going to be soaking them in both a bottle of Mountain Dew, and a bottle of Coca-Cola for the next three weeks. So let's see what happens! These teeth have been soaking in the soda for two weeks and five days. Before we take them out and weigh them, let's get a little background on this soda. So the Mountain Dew right here has a pH of around 3.1 whereas the Coca-Cola has a pH of 2.5 making it six times more acidic than the Mountain Dew. So let's take these teeth out, and see how much their mass has changed. I'm going to pour the Mountain Dew out here, and get the tooth out… I got the tooth out, and as you can see, it looks a lot more yellower, especially at the base of it, than before. Whoa, whoa, whoa... This tooth does not look very good at all. It is all black around the crown, and it just looks disgusting and nasty. So I'm going to clean it up with a little bit of water. So now that I've gotten these teeth dried off, if you look really closely, you can actually see that a lot of the enamel that was there — the white stuff — is gone where it previously was before. And on the Coca-Cola tooth, you can't really see a whole lot, because it's so stained. Now the teeth are sufficiently dried off, let's weigh them. So the Coca-Cola tooth weighs .80 g, meaning that it's .06 g lighter than it was before. Now, if you look at the Mountain Dew tooth, we can see that it is .81 g, meaning that it is 13 hundredths of a gram lighter than it was before. Now if we adjust for the initial mass of the teeth, we can see that the Mountain Dew tooth lost 14% of its mass, while the Coca-Cola tooth only lost 7% of its mass. Half of what the Mountain Dew lost. Since Coca-Cola is six times more acidic than Mountain Dew, you would expect it to have a higher decay rate than Mountain Dew. This is not the case for two factors. And that first factor is titratable acidity, or TA. So pH is a measure of the level of acidity. That means that Coca-Cola is more acidic than Mountain Dew. However, Mountain Dew has a higher titratable acidity than Coca-Cola. Meaning that it has more acid than Coca-Cola. This means that it takes longer for the saliva in your mouth to dilute that acid than it would for most cola drinks. In addition to this, it's also the type of acid that's added that makes the difference. So Mountain Dew, just like most non-cola beverages, has citric acid added into it. And citric acid is an organic acid, meaning that it will be able to break down the calcium in your teeth faster than inorganic acids like the phosphoric acid found in most cola beverages. This ultimately means that Mountain Dew is worse for your teeth than Coca-Cola, even though Coca-Cola is way more acidic and that's something that you might not have known. Thanks, Tom. Thanks, Chase! Thought I'd left that catchphrase behind. Go subscribe to his channel, he's got some wonderful videos coming up, links on screen or in the description now. Let's face it, he's going to have my job in 5 or 10 years' time, you're getting in early. Next time, we have, well, a very familiar part of China.