Cold kettle, also called cold kettle at ordinary times, can put hot water there to drink cold.

Water has many important functions in the body:

(1) water is an important part of cell protoplasm;

(2) Water acts as a solvent in the body to dissolve various electrolytes;

(3) Water plays a transport role in the body, which can transfer nutrients, metabolic wastes and endocrine substances (such as hormones);

(4) Water has high thermal conductivity and specific heat, and can be used as a "heat carrier" to transfer heat between the body and the skin surface, which helps to regulate body temperature.

Many common gases can be dissolved in water, such as hydrogen, oxygen, nitrogen, carbon dioxide, inert gases and so on. The solubility of these gases is related to temperature, pressure and gas phase partial pressure.