Rice Kettlebells

Take a vessel and pour some granular material into it, for example, rice. If you dip e.g. a spoon into it, then at a certain depth of immersion, you can lift the vessel and contents by holding the spoon. Explain this phenomenon and explore the relevant parameters of the system.

在一个容器中倒入一些颗粒状物质（如大米）。如果把勺子浸入其中且达到一定浸入深度，就可以通过握住勺子把从而提起该容器及其内部颗粒物质。解释这一现象并探究系统的相关参数。