Propulsion based on the phenomenon of surface tension of the liquid. Drawing, description

MODELING
Free library / Directory / Modeling

Propulsion based on the phenomenon of surface tension of the liquid. Tips for a modeler

Modeling

The phenomenon of liquid surface tension has been known for a long time, and with the invention of a new material - nanocellulose, it became possible to create an interesting propulsion device for a toy boat model.

Issue 24 of 2012 of the journal "Chemical Science" published an article describing a model of a boat propelled by the evaporation of a surfactant. Alcohol is used as this substance, the chemical energy of which is converted into mechanical energy, this energy sets the boat model in motion. Evaporating, the alcohol penetrates the membrane (liquid-tight boat hull made of nanocellulose), which leads to a decrease in the surface tension of water in the stern. Due to the difference in surface tension of the water in front of and behind the boat, it moves forward.

Changing the surface tension of water sets the boat in motion (click to enlarge)

It is interesting to note that a similar mover was described in the book "Entertaining experiments in physics" (L.A. Gorev, 1985).

Cut out a plate from cardboard, the shape of which is shown in the figure, and lower it onto the surface of water poured into a glass bath of sufficiently large dimensions, for example, 35 cm in diameter and 10 cm high. Place a camphor crystal on the water in the center of the cardboard cutout. The plate moves for a long time. Why?

Propulsion based on the phenomenon of liquid surface tension
Boat with camphor engine

A similar description of a similar mover is in the physics textbook (General course of physics. Thermodynamics and molecular physics. vol. II. D.V. Sivukhin. M., Nauka, 1990):

Many phenomena are explained by the fact that the surface tension of different liquids is not the same. Take, for example, a small model boat made of tin, in the stern of which a small hole is made. Let's pour some ether into the boat so that the level of the free surface of the ether is slightly higher than the hole. Then let the boat float on the surface of the water. Then he will begin to move forward, i.e. in the direction from stern to bow. The phenomenon is explained by the fact that the surface tension of ether is less than the surface tension of water. The ether seeping through the hole in the stern covers the surface of the water behind the boat with a thin layer. The surface tension of the ether pulls the boat back. However, this force is less than the surface tension of water, which pulls it forward. The resultant of these two forces is directed forward and sets the boat in motion.

The same phenomenon is observed when small pieces of camphor are thrown onto the surface of pure water. Camphor slowly dissolves in water and reduces its surface tension. The rate of dissolution in different places of a piece of camphor is not the same and depends on its shape. It is more near the protruding sharp ends of the piece. As a result, a difference in surface tension is formed, leading a piece of camphor into a random and intense rotational and translational motion. The phenomenon is observed only when the surface of the water is sufficiently clean. A thin layer of fat reduces the surface tension of water to such an extent that the dissolution of camphor can no longer reduce it further. According to Rayleigh, the movement of camphor stops when the thickness of the oil layer on the water surface reaches 2 * 10-7 cm. In this case, the surface tension of water is 28% less than for a clean water surface. A layer of oil with a thickness of 1 * 10-7 cm and below, according to Rayleigh, has practically no effect on the surface tension of water.

And another description of the mover based on the surface tension of the liquid was published in the journal "Kvant", 1982, No. 11.

A moving "rocket" and divergent rings.

Cut out a paper "rocket" of the shape shown in Figure 1, a. At point A, place a drop of concentrated soap solution or a small bar of soap. If you now lower the rocket on a calm surface of the water, then it will begin to move.

Propulsion based on the phenomenon of liquid surface tension
Rocket and spinner

Instead of a "rocket", you can make a pinwheel in the shape of the letter S and place pieces of soap at points A and A' (Fig. 1, b). Observe in which direction the spinner will rotate.

We recommend interesting articles Section Modeling:

▪ Stirling engine model

▪ steam engine ship model

▪ Submarine life buoy

See other articles Section Modeling.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

A New Way to Control and Manipulate Optical Signals 05.05.2024

The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>

Primium Seneca keyboard 05.05.2024

Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Random news from the Archive

Subcutaneous chip for instant blood test 12.06.2015

Scientists from the Federal Polytechnic School of Lausanne (Switzerland) have developed a diagnostic chip that is implanted under the skin.

To perform a real-time blood test and immediately obtain data on the content of various substances in the blood, it is enough to implant a microchip with a side of only one square centimeter under the skin.

The device can measure cholesterol and blood glucose levels, as well as certain medications. Inside, there is a control unit, a set of six sensors, a Bluetooth adapter for connecting to a smartphone, and an induction circuit.

This design is due to the need to place an "external" battery, so that you do not have to cut the skin every time to replace the battery - the battery is simply glued to the skin with a regular patch.

The researchers have already tested the microchip in lab mice, and human trials should begin within the next five years.

Other interesting news:

▪ Travel suitcase with electronics

▪ HTC is ditching QWERTY keyboards and big batteries

▪ Sound can travel even in a vacuum

▪ Tidal floods are associated with a special type of slow ocean wave.

▪ Mobile phone SAMSUNG SCH-X820

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Tips for radio amateurs. Selection of articles

▪ An article by Anna de Stael. Famous aphorisms

▪ What were the ways of unifying Germany in the XNUMXth century?

▪ Bachman Knot article. Travel Tips

▪ article Electrical insulating varnished fabrics (varnished fabrics). Encyclopedia of radio electronics and electrical engineering

▪ article Operating model of a water turbine. physical experiment

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews