A life hack I've learned a long time ago is that when cooking noodles or porridge in a small pot, if you place a pair of chopsticks or a wooden spoon horizontally across the pot, it will never overflow.
I believe many people have faced the situation where, every time they cook soup on high heat, the pot overflows, causing the cooking utensils to get dirty and potentially causing a gas leak, which can be very dangerous.
At this point, placing a wooden spoon horizontally can reduce the size of the bubbles. The radius of curvature at the point where the pot's edge and spoon meet is very small, which significantly increases the pressure difference between the inside and outside, as derived from Laplace's formula.
Additionally, wood is a poor conductor of heat and will only work for a limited amount of time. Therefore, when exposed to the bubbles of water at 100°C, the low temperature of the spoon will cause the steam to immediately condense back into water and drip down, preventing the water from continuing to overflow.
This is in stark contrast to the reaction when using a metal spoon. Metal is an excellent heat conductor. When placed in the pot, it quickly heats up — sometimes even faster than the water in the pot. When water comes into contact with the smooth, hot surface of the metal spoon, it overcomes the metal barrier and quickly overflows.
However, you need to keep in mind that repeated water overflow will wet the wooden spoon, making it heat up and gradually lose its effectiveness. So, after a certain amount of time, you should return and turn off the heat instead of relying entirely on the wooden spoon to stop the overflow. The longer the water boils, the more bubbles will form, and the pot will start to boil over again.
Note: To get the best effect from this trick, when placing a wooden spoon horizontally on a boiling pot, choose one with a larger size. Generally, this trick works for all cooking situations where water and foam are likely to overflow. If you need to step away for a short time, this little tip can be applied.