15 FEATURED CAPILLARITY EXAMPLES - SCIENCE - 2025

Capillarity, a characteristic of liquids, is the phenomenon that makes the surface of a fluid that comes into contact with a solid body rise or fall. In addition to that it may or may not wet the element in question.

This property depends on the surface tension of the liquid. This tension provides resistance to the new object that comes into contact with the liquid. Surface tension is related to the cohesion of the fluid that we are observing.

Capillarity effects

Depending on the surface tension that is present at that moment, the liquid can rise or fall through the capillary tube. That is why it is known as capillarity.

The less cohesion of the liquid molecules, the fluid adheres to the new body that comes into contact with it. The fluid is then said to wet the new body and move up the duct. The ascent will continue until the surface tension balances.

Featured examples of capillarity

Surface tension in insects

Some insects can walk through water, this is because the weight of the insect is compensated by the resistance of the water when it is deformed.

Glass capillary tube

If we put a glass tube in a container of water, the water level will rise through the tube.

If we introduce a larger diameter tube, the water will stay at a lower level. The surface of the liquid will be left with a concave shape called a meniscus.

Capillary tube in mercury

If we introduce a capillary tube into the mercury, the level of this will rise through the tube but at a lesser rate than the water.

In addition, its surface will present a convex curvature of an inverted meniscus

Surface tension in sheets

As with insects, the surface tension that is created makes the leaf or some flowers float in the water without sinking, even though their weight is greater than that of water

Plant feeding

Through the phenomenon of capillarity, plants extract water from the soil and transport it to their leaves.

Nutrients rise through the capillaries of plants until they reach all parts of the plant.

Sap rise in trees

The sap ascends along the tree thanks to the capillary process. The rise is due to the fact that in the leaves there is an evaporation of the liquid that causes a negative pressure to be produced in the xylem, causing the sap to rise due to the action of capillarity. It can reach a height of 3 km of ascent.

With a paper napkin

If we place a paper napkin that touches the surface of the water and leaves the container, through the capillary process the water can move through the napkin, leaving the container.

Water transfer

Just as we can make the liquid come out of the container, as in the previous example, if we connect two containers through an absorbent material such as a paper napkin, the water from one container will pass to the other.

Detergents and soaps over water

There are some detergents and soaps that have chemical compounds that make them settle on water and the surface tension prevents them from sinking.

Ascension of water on the ground

The capillarity of some soils causes the water to rise through the ground to exceed the water table, despite the fact that it is a movement contrary to gravity.

Moisture on the walls

The capillarity that some walls present makes water seep into them and into the houses.

This causes that in houses there is a greater concentration of water molecules in the air, which is known as humidity.

Dipping cookies

When we dip the cookies in milk at breakfast, the action of the capillarity causes the milk to enter the cookie, thus increasing its liquid capacity.

As the milk rises through the biscuit, it undoes the cohesion forces of the solid and therefore the biscuit breaks.

Butter candles

If we take a piece of butter and stick a wick in it and light it with a match, it will burn.

However, butter that is in contact with oxygen in the air does not burn. This happens because the capillarity of the candle allows the melted butter to rise through the wick and function as a combustion fuel.

Sugar cubes

The capillarity of sugar cubes means that if we put them in contact with a liquid, such as water, the sugar cubes absorb it in a way that they retain the liquid within them.

If the liquid is in a higher concentration than the sugar cube, it can cause the cohesion forces of the sugar cube to be broken.

Capillarity with flowers

To observe the phenomenon of capillarity that occurs in plants, we can immerse the stem of a flower in a container with a colorant.

Through the capillarity of the flower, the water will rise up to its petals and change their color.

Capillarity of the land

For water to rise to the surface of a land, the land has to be porous. The more porous the ground, the lower the adhesion forces of the water, so the water will seep more.

For example, soils with sand and gravel, being more porous, drain the water quickly, while clay soils, the water does not drain and forms puddles since the pores are much smaller

References

1. Peiris MGC, Tenmakone K.. Rate of rise of a liquid in a capillary tube. J. Phys. 48 (5) May 1980, pp. 415
2. ROWLINSON, John Shipley; WIDOM, Benjamin. Molecular theory of capillarity. Courier Corporation, 2013.
3. DE GENNES, Pierre-Gilles; BROCHARD-WYART, Françoise; WHAT, David. Capillarity and wetting phenomena: drops, bubbles, pearls, waves. Springer Science & Business Media, 2013.
4. MULLINS, William W. Flattening of a nearly plane solid surface due to capillarity. Journal of Applied Physics, 1959, vol. 30, no 1, p. 77-83.
5. MAYAGOITIA, V.; KORNHAUSER, I. Potential for Adsorption and Capillarity. In Memories of the VI Congress of the National Academy of Engineering. 1980. p. 238-242.
6. RUIZ, VICENTE PAZ. The teaching of biology in preschool and primary school through conceptual organizers, a case of the plant concept.