|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
CHILDREN'S SCIENTIFIC LABORATORY
cumulative effect. Children's Science Lab
Directory / Children's Science Lab Cumulative action is the phenomenon of the concentration of an explosion in a given direction. A recess is made in the explosive charge, the surface of which is covered with a metal lining. During the explosion, the lining is strongly compressed, and the metal under the influence of high pressure acquires the properties of a liquid. As a result, a thin metal jet is ejected from the compressed shell at a speed of 12-16 km/s. The energy density in the jet is comparable to the energy density of a nuclear explosion. It is not surprising that it is able to burn through even very thick armor. Today we bring to your attention several experiments that will help you experiment with the cumulative effect, but, we note, without a single gram of explosives. Remember, if you slap your hand on the water, and turn your palm at an angle, a thin strong jet is born ... And having a school tripod and a simple device consisting of a rod with a spatula, you can set up an even more scientific experiment, and determine the speed by the range of the "shot" jets. It is not difficult to calculate with what speed the blade touched the water (because we ourselves choose the height of the fall of the rod), thereby we can find out how much the speed multiplies due to the amazing cumulation effect, namely 10 - 15 times, as in real explosions.
A simple and beautiful experience can be made with a quick immersion in the water of a funnel. Just don't get too carried away: the jet easily reaches the ceiling. And this is what happens: the walls of a moving funnel create a flow of water converging to its axis. Colliding, the liquid jets slow down, and, as a result, the pressure increases. When applied to a small amount of water at the throat of the funnel, it imparts considerable speed to it. And the whole essence of the effect is that the energy of a slowly moving flow with a large mass is transferred to a flow that has a smaller mass, but its speed is several times greater.
Our experiments with a spatula or a funnel provide food for thought on impulse hydraulic pumps for supplying small masses of liquid under high pressure. This is one of the "blank spots" in modern technology. If we were to create a pump capable of injecting one cubic millimeter of gasoline into the cylinder of a motorbike engine per piston stroke, and at a pressure of 4-5 MPa, then we could travel at least 1000 km in one refueling of the tank. It's great, isn't it? It is not possible to solve this problem only by a rough reduction of a conventional fuel pump - it is very difficult to make it even in a single copy. Cunning hydrodynamic effects will help us figure this out.
Here is another curious experience, where the same cumulative effect is manifested. Throw a ball into the water. After repeating the experiment several times, you will notice, or rather, you will feel that the ball leaves a funnel in the water. Its walls collapse, and a thin, needle-like trickle of water rises up. But there is one subtlety here. Even such an obvious effect in experiments is not always possible. It turns out that the surface of the ball should be covered with fat.
A similar phenomenon occurs when a drop of water falls into water. It is curious that at the top of the cumulative jet (this can be seen in the pictures) tiny droplets form. Due to their small size, they are able to float in the air like dust particles. This beautiful effect is used in the construction of fountains. But American scientists have discovered that it also occurs when flushing ... the toilet, due to which the contents in microscopic doses are in the air. Doctors see this as one of the channels for the spread of dangerous diseases, and engineers - an excellent reason for reflection. In the British Museum, the portraits of the inventor of the steam engine and the inventor of the toilet Brama are side by side. They are regarded as the greatest benefactors of mankind, and it is not known who is more important ... However, let's better experiment with explosions. And we will immediately answer the "crown" question of many letters received by the editor: "Is it possible to make explosives at home?" We answer: "It is possible, but it is impossible to stay alive!" However, the main task of explosives is the release of mechanical energy at high speed and in a given volume. For example, TNT is capable of releasing about 2000 kJ of mechanical energy per cubic centimeter. You and I, without risking anything, will conduct experiments with a substance at least ten times more powerful. It's... a plasma that forms after an electrical discharge in water. So, we will assemble the installation, the diagram of which is shown in the figure. It consists of a capacitor (1-3 thousand pF, 24 kV), a plastic cuvette with distilled water and two spark gaps. We connect the capacitor to a high-voltage source "Discharge-1" or an electrostatic machine. As the capacitor charges, the potential difference across the air-gap electrodes increases and self-discharge occurs. The resulting current pulse creates a discharge between the electrodes in the water. The effect it creates is equivalent to a miniature explosion of a heavy-duty explosive. We warn you: an increase in the capacitance of the capacitor does not add anything fundamentally new to the observed effects, but it becomes dangerous to work with the installation.
By producing discharges at a depth of 5-10 mm, one can observe water sultans, similar to a wave from a depth bomb explosion. Try to assemble a device with a discharge gap in a piece of transparent hose. Seal the wire entries with plasticine. After fixing the device in a tripod, fill it with water and discharge. The meniscus formed by the water will collapse, and a thin cumulative jet will splash high under the ceiling.
An electrical circuit for obtaining underwater electrical discharges: a high voltage source, a capacitor and two discharge devices. One of them, with an air discharge gap of about two centimeters, serves to form a pulse. Passing through the water, an electrical impulse will create an explosive effect in the second discharge device with a gap of 1-2 mm. All conductors immersed in water must be well insulated! Many different devices can be proposed in which a cumulative effect occurs without the participation of an explosive. In our experiments, its consequences were absolutely safe for others for only one reason - the negligible energy of the processes. But when devices for crushing stones or other similar devices that require high energies are created on their basis, they will become dangerous, although they do not contain any explosive. However, a jackhammer or a metal-cutting machine also requires only "you" to be addressed. Author: A. Saveliev
▪ What is the real shape of the earth? ▪ Electric motor from paper clips
Artificial leather for touch emulation
15.04.2024 Petgugu Global cat litter
15.04.2024 The attractiveness of caring men
14.04.2024
▪ Biological time can be determined by a blood test ▪ Hiking is dangerous for nature ▪ Billionth mouse from Logitech
▪ section of the site Art video. Article selection ▪ article New Chronology. History and essence of scientific discovery ▪ article Who is a sea elephant? Detailed answer ▪ article High-voltage testing of dielectric gloves. Standard instruction on labor protection ▪ article Sulphurous dyeing of fabric and yarn. Simple recipes and tips ▪ article Guessing stacks of cards. Focus Secret
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
We recommend interesting articles Section 
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page