The expression "to carry water with a sieve" means wasting time, doing pointless or impossible work. However, this venture is not so hopeless as it might seem at first glance.
The fairy tale is a lie, but there is a hint in it
The task to bring water in a sieve is found in the tales of many peoples. For example, in a Russian fairy tale, the stepmother drives her stepdaughter out of the house, and she is hired as a service to Baba Yaga, who orders to heat the bathhouse and draw water with a sieve. The girl is rescued by a magpie who shouted "Glinka, Glinka" to her. As a result, having coated the bottom of the sieve with clay, the heroine successfully copes with the difficult work.
In an English fairy tale, the plot is very similar - the stepmother wants to get rid of her step-daughter and sends her to a forest lake. The stepdaughter must return home with a full sieve of water, without spilling a drop along the way. A frog comes to the rescue, which, in exchange for a promise to take her into the house, advises to plug the holes in the sieve with moss and smear the bottom with clay. This fairy tale has a happy ending - the stepdaughter returns with a full sieve of water, and the frog turns into a handsome prince in the morning.
Plots related to carrying water in a sieve are also found in Indian, Turkish, Italian fairy tales. And in many cases, the ability to bring water in a sieve proves the heroine's purity and innocence. The first such legend can be considered the Roman myth about the Vestal woman Tuccia, who, in response to a false accusation, scooped up water from the Vesta River with a sieve and carried it in front of all the people.
Is it possible to carry water in a sieve
The first thing that comes to mind is to wait for the onset of cold weather and transfer the water in the form of rain or snow. But what if the condition is not to change the physical state of water? Is it possible to cope with this task?
According to physicists - yes, you can. Subject to certain conditions:
- as the fairy-tale characters suggested, the main secret lies in the treatment of the bottom - it should not be wetted with water. To do this, the sieve is carefully covered, for example, with a thin layer of paraffin, and so as not to close the holes;
- pour water into the sieve very carefully. A strong jet of water will break the protective coating;
- it should be carried smoothly, the sieve should be held strictly horizontally and in no case should it be shaken.
If you know the area of the sieve, as well as the number and size of its cells, then, taking into account the coefficient of surface tension of water (α = 0, 073N / m), it is easy to calculate how much liquid you will be able to convey. So, to transfer a glass of water with a volume of 250 grams, you will need a sieve with an area of 0.1 m2. At its bottom there will be a thousand cells, each with an area of 1 mm2.
Why carry water with a sieve?
For the ancient Slavs, the sieve was not just a kitchen utensil. He was credited with wonderful properties, considered a symbol of fertility and a well-fed life. And the water spilled from the sieve was compared to rain or sunlight. It was believed that she could heal from disease and protect from danger.
Such water was poured over at the wedding of the young, and it was poured on the ground, "so that everything would go on and give birth." Children were bathed through a sieve, sprinkled on pets. Used water spilled through a sieve, and fortune-telling. Many sayings and proverbs associated with the sieve have survived to this day. Although over the years the meaning of many of them has changed dramatically.