Water experiments

Antique paper texture

In the first picture, we can see the water that, does not overflow from the glass because a kind of "elastic skin" is formed on the surface, due to the cohesive force of the molecules in contact with the air. In the second picture we can see, the experiment of the floating paper clip.

E-Twinning Project 2021/2022 Agenda 2030 Water Fratta Todina Primary School

The experiment of mixing water with flour, salt, sugar and oil. The salt and sugar combine with the water to form a solution; the flour remains suspended and produces a suspension; the oil floats without mixing, producing an emulsion.

All these properties, we learnt make water vital for biological processes that take place in nature.

SURFACE TENSION surface tension is the cohesive force between water molecules . This phenomenon allows some light insects to walk on water without breaking the bonds between the surface molecules. It also explains the spherical shape of drops or the filling of a glass a couple of millimetres over the edge, avoiding overflow.

CAPILLARITY Capillarity is the tendency of water to rise through a narrow space by overcoming the force of gravity. It is the phenomenon of capillarity that allows water to be absorbed by the roots and to reach the leaves where chlorophyll photosynthesis takes place.

The pepper that can be seen move away from the center of the dish where a drop of soap has fallen which breaks the cohesive bonds of the water molecules.

Paper flowers that are opening by the raising of water through a narrow space...

SOLVENT POWER It is the property of a substance to dissolve another substance. Water is one of the best solvents in nature because it is able to break the bonds that unite the molecules of several substances. Salt and sugar are dissolved in few minutes. This property allows water to mineralize while passing through the rocks. The solvent power of water lets human body to absorb minerals and vitamins. Moreover it allows the nutrient transport to cells and the elimination of waste substances.

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