Why Ketchup Is Hard to Get Out of a Bottle

Consider ketchup: The confounding condiment just loves clinging to the bottom of a bottle despite vigorous thwacks to coax it from its glassy confinement. This is especially maddening if a fresh batch of crisp fries are arranged, naked and ketchup-less, in front of you.

But it’s not ketchup’s fault, OK? According to a new video from Ted-Ed, it can’t help being this way. Ketchup is a non-Newtonian solid (try saying that three times fast), which means that sometimes it behaves like a liquid, and other times like a solid.

This is because ketchup’s non-homogeneous chemical makeup—pulverized tomato particles that sit in a liquid of water, vinegar, sugar, and spices—makes it difficult to predict how it’s going to behave. In fact, scientists still don’t completely understand what happens within a ketchup bottle when you shake it in certain ways.

Although the video doesn’t address the classic tap-it-on-the-57-logo espoused by Heinz, it states that there are two ways to get ketchup out of a bottle: smack its bottom once really hard, or shake the bottle slowly and consistently. Stick to these methods, and you’ll chow down on those fries sooner rather than later.

[via Laughing Squid]