Why do Mentos and Diet Coke React?

TL;DR

Mentos has small pores on its surface that disrupt the polar attractions between water molecules, creating ideal nucleation sites for gas molecules in carbonated beverages to congregate and rapidly form bubbles, resulting in a foamy explosion when combined with Diet Coke.

Transcript

If you’ve ever wondered why Diet Coke and Mentos react so strongly to one another, well, wonder no more. To start, it should be noted that it’s not just Diet Coke and Mentos that “react”; other carbonated beverages will also readily respond to the addition of Mentos. What’s going on here is that Mentos has thousands of small pores on its surface di... Read More

Key Insights

• 🫢 Mentos' porous surface disrupts polar attractions between water molecules, creating nucleation sites for gas bubbles.
• 👁️‍🗨️ The surface tension-lowering ingredients in Mentos and Diet Coke enhance bubble growth on the porous surface.
• ☠️ The sinking rate of Mentos, temperature of the soda, and addition of surfactants can impact the size of the explosion.
• 😅 The myths about people dying from drinking Diet Coke and eating Mentos are unfounded.

Questions & Answers

Q: Why do Diet Coke and Mentos create a violent reaction?

When Mentos is added to Diet Coke, the small pores on the Mentos' surface disrupt the polar attractions between water molecules, creating numerous nucleation sites for gas bubbles to form rapidly.

Q: Does the type of Mentos affect the reaction?

Smooth-surfaced Mentos won't create a strong reaction because they lack the small pores that enhance bubble formation. The porous surface of regular Mentos provides ideal nucleation sites for gas molecules.

Q: Why do diet sodas produce a bigger reaction than regular sodas?

Diet sodas like Diet Coke contain aspartame, which lowers the surface tension of the liquid more than sugar or corn syrup. This lower surface tension enables more rapid bubble growth on the porous surface of Mentos, resulting in a larger explosion.

Q: Can caffeine increase the explosive reaction between Diet Coke and Mentos?

Caffeine does not significantly affect the reaction, as the small amount present in a typical 2-liter bottle of soda does not have a noticeable impact. High levels of caffeine required to make a difference would be toxic.

Summary & Key Takeaways

• Mentos has small pores on its surface that disrupt the polar attractions between water molecules, providing ideal sites for gas molecules to congregate and form bubbles.

• The gum arabic/gelatin ingredients and aspartame/sugar in Mentos and Diet Coke lower the surface tension of the liquid, allowing for rapid bubble growth on the Mentos' porous surface.

• The temperature, sinking rate of Mentos, and addition of surfactants can also affect the size of the Diet Coke and Mentos explosion.