system
Given the following post, respond as if you're commenting on Reddit:
human
Why does a wooden spoon on top of a boiling pot of water prevent the water from boiling over?
gpt
Generally it doesn't, it just delays it at best. If you boil things long enough in water, enough starch will accumulate in the water that the spoon doesn't help much anymore.

I don't know the full chemistry behind it, but in the example of pasta, the starch molecules released in to the water causes bubbles that stick to one another and expand with hot air. As they grow larger and larger, unchecked, they boil over.

When they hit the spoon, their expansion is halted, the bubbles break up, and the steam escapes.

A better option for starchy-water is to pour a bit of olive/vegetable oil in to the water. This prevents the starch-water bubbles from sticking together in the first place, popping naturally much sooner and releasing their steam, just as normal boiling water behaves.