Add a few drops of detergent to the water, will the coins still float on the water?

No, if it is added to a certain amount, the detergent will reduce the surface tension of water and make it difficult for coins to float on the water.

Related introduction:

Tension of interaction between any two adjacent parts of a liquid surface perpendicular to the dividing line of unit length. The formation of surface tension is closely related to the special stress state of molecules in the liquid surface thin layer. The existence of surface tension forms a series of special phenomena that can be observed in daily life.

A liquid like water will produce a force to make the surface as small as possible. This force is called "surface tension". In the morning, the water droplets condensed on the leaves and slowly hanging from the faucet are formed under the action of surface tension. In addition, water strider can stand on the water because of the surface tension.

At room temperature (about 20℃), the surface Zhang Liwei of most liquids is 20? 40 dynes/cm, but there are also more than this number, such as the surface tension dimension of water is 72 dynes/cm; The Zhang Liwei on the surface of mercury is 470 dynes/cm. The surface tension of liquid metal is relatively large. For example, the surface tension dimension of liquid copper is1131℃1103 dyne/cm.

Some elements that are gaseous at room temperature have little surface tension when they are liquid at low temperature. For example, the surface tension of 4.3 liquid helium is only 0.098 dyne/cm, and the surface tension dimension of 90.2 liquid hydrogen is 0.2 dyne/cm. Theoretical analysis also points out that the surface tension decreases with the increase of temperature for the same liquid.