沉底

rú guǒ xiàng chí táng li rēng yī gè mù sāi tā bù huì chén dǐ ér huì piāo qǐ lai

如果向池塘里扔一个木塞，它不会沉底而会漂起来。

If we throw a piece of cork on to pond, it will not sink to the bottom. Instead, it will float.