During his period of leave, the British YouTuber Tom Scott leaves the floor to five videographers for us present new exciting things. This time, it's Steve Mould, a television presenter and expert in the field of science, on the following topic: the hot water and cold water do not make the same noise when paid in a Cup. Thanks to an intuitive knowledge, we notice that it is easier to differentiate using only our hearing. This difference lies in the fact that the viscosity of water is reduced when it is heated. By pouring the water, the way that she filled the Cup is influenced by its level of viscosity, which changes the noise by complex reactions of fluid dynamics.