What is directed motion of charged particles? For many, this is an incomprehensible sphere, but in fact, everything is very simple. So, when they talk about the directional movement of charged particles, they mean current. Let's understand its basic characteristics and formulations, and also consider safety issues when working with it.
general information
Begin with a definition. By electric current is always meant the ordered (directed) movement of charged particles, which is carried out under the influence of an electric field. What kind of objects can be considered in this case? By particles are meant electrons, ions, protons, holes. It is also important to know what the current strength is. This indicates the number of charged particles that flow through the cross section of the conductor per unit time.
Nature of the phenomenon
All physical substances are made up of molecules that form from atoms. They are also not the final material, because they have elements in themselves (the nucleus and electrons rotating around it). All chemical reactions are accompanied by particle motion. For example, with the participation of electrons, some atoms will lack them, while others will experience an excess. In this case, the substances have opposite charges. If their contact occurs, then the electrons from one will tend to move to another.
This physical nature of elementary particles explains the essence of electric current. This directed movement of charged particles will occur until the values ​​are equalized. In this case, the reaction of changes is chain. In other words, instead of a departed electron, another one comes in its place. For replacement, particles of a neighboring atom are used. But the chain does not end there. An electron can also come to the extreme atom, for example, from the negative pole of the source of the flowing current.
An example of such a situation is a battery. From the negative part of the conductor, the electrons move to the positive pole of the source. When all particles in the negatively infected component end, the current stops. In this case, they say that the battery has "run out". What is the rate of directional movement of charged particles moving in this way? Answering this question is not as easy as it might seem at first glance.
Voltage role
What is the concept used for? Voltage is called the characteristic of the electric field, which is the potential difference of two points that are inside it. This may not seem very clear to many. When it comes to the directed (ordered) movement of charged particles, you need to understand the voltage.
Imagine that we have the simplest conductor. This may be a wire made of metal, for example, copper or aluminum. In our case, this is not so important. The mass of the electron is 9.10938215 (45) Ă— 10 -31 kg. This means that he is quite material. But the metal of the conductor is solid. How, then, can electrons flow through it?
Why there may be current in metal products
Let's look at the basics of chemistry, which each of us had the opportunity to study at school. If the number of electrons in the substance is equal to the number of protons, then the neutrality of the element is ensured. Based on the periodic law of Mendeleev, it is determined what substance has to be dealt with. It depends on the number of protons and neutrons. One cannot ignore the big difference between the masses of the nucleus and the electrons. If you remove them, then the weight of the atom will not change.
For example, the mass of a proton at about 1836 is greater than the value of an electron. But these microscopic particles are very important, because they can easily leave one atom and join another. In this case, a decrease or increase in their number leads to a change in the atomic charge. If we consider a single atom, then its number of electrons will always be variable. They constantly leave him and come back. This is due to thermal motion and energy loss.
Chemical specificity of a physical phenomenon
When there is directed movement of electrically charged particles, is the atomic mass lost? Does the composition of the conductor change? This is a very important misconception that confuses many. The answer in this case is only negative. This is due to the fact that chemical elements are determined not by their atomic mass, but by the number of protons that are in the nucleus. The presence or absence of electrons / neutrons in this case does not play a role. In practice, it looks like this:
- Add or remove electrons. It turns out the ion.
- Add or remove neutrons. It turns out an isotope.
The chemical element does not change. But with protons the situation is different. If it is only one, then we have hydrogen. Two protons - and we are talking about helium. Three particles are lithium. And so on. Who is interested in the continuation, he can see the periodic table. Remember: at least a thousand times the current will pass through the conductor, its chemical composition will not change. But something else is possible.
Electrolytes and other interesting points
The peculiarity of electrolytes is that it is their chemical composition that changes. Then, under the influence of current, electrolyte elements are released from the solution. When their potential is exhausted, the directed motion of charged particles will cease. This situation is due to the fact that ions are carriers of charges in electrolytes.
In addition, there are chemical elements generally without electrons. An example is the following:
- Atomic cosmic hydrogen.
- All substances in a plasma state.
- Gases in the upper atmosphere (not only the Earth, but also other planets where there are air masses).
- The content of accelerators and colliders.
It should also be noted that under the influence of electric current, some chemicals can literally crumble. A well-known example is a fuse. How does it look at the micro level? Moving electrons push atoms in their path. If the current is very strong, then the crystal lattice of the conductor does not withstand and is destroyed, and the substance melts.
Back to speed
Previously, this point was superficially affected. Now let's pay him more attention. It should be noted that the concept of the directional velocity of charged particles in the form of an electric current does not exist. This is due to the fact that different quantities are intertwined. So, an electric field propagates along a conductor at a speed that is close to the movement of light, that is, about 300,000 kilometers per second.
Under its influence, all electrons begin to move. But their speed is very low. It is approximately 0.007 millimeters per second. At the same time, they also randomly rush about in thermal motion. In the case of protons and neutrons, the situation is different. They are too large for the same events to occur. As a rule, talking about their speed, as close to the value of light, is not necessary.
Physical parameters
Now let's look at what the movement of charged particles in an electric field is from a physical point of view. To do this, imagine that we have a cardboard box in which 12 bottles of carbonated drink are placed. At the same time, there is an attempt to put another container there. Suppose it succeeded. But the box barely survived. When you try to put another bottle in it, it breaks, and all the containers fall out.
The box under consideration can be compared with the cross section of the conductor. The higher this parameter (thicker the wire), the greater the current strength it can provide. This determines how much directed movement of charged particles can have. In our case, a box in which there is from one to twelve bottles can safely fulfill its intended purpose (it will not break). By analogy, we can say that the conductor will not burn.
If you exceed the designated value, the object will fail. In the case of a conductor, resistance will come into effect. Ohm's law very well describes the directed motion of electrically charged particles.
The relationship of different physical parameters
You can put one more on the box from our example. In this case, it will be possible to place not 12 but 24 bottles per unit area. Add one more - and there are already thirty-six of them. One of the boxes can be considered as a physical unit, similar to voltage.
The wider it is (at the same time the resistance decreases), the more the number of bottles (which in our example replace the current strength) can be placed. By increasing the stack of boxes, additional containers can be placed per unit area. In this case, the power grows. In this case, the box (conductor) is not destroyed. Here is a brief summary of this analogy:
- The total number of bottles increases power.
- The number of containers in the box indicates the current strength.
- The number of boxes in height allows you to judge the voltage.
- The width of the box gives an idea of ​​resistance.
Possible dangers
We have already figured out that the directed motion of charged particles is called current. It should be noted that this phenomenon can be dangerous to human health and even life. Here is a short list of electrical current properties:
- Provides heating for the conductor through which it flows. If the household electrical network is overloaded, then the insulation will gradually char and crumble. As a result, there is the possibility of a short circuit, which is very dangerous.
- Electric current, when it flows through household appliances and wires, meets the resistance of the elements that form the materials. Therefore, he chooses a path in which the value of this parameter is minimal.
- If a short circuit occurs, the current strength increases sharply. A significant amount of heat is released. It can melt metal.
- Short circuiting may occur due to moisture. In the cases considered earlier, nearby objects light up, but in this variant people always suffer.
- Electric shock carries a significant danger. Even a fatal outcome is likely. When an electric current flows through the human body, the tissue resistance is greatly reduced. They begin to heat up. In this case, the cells are destroyed and the nerve endings die.
Security questions
To avoid exposure to electric current, it is necessary to use special protective equipment. Work should be carried out in rubber gloves using a mat of the same material, discharge rods, as well as grounding devices for workstations and equipment.
Circuit breakers with different protection proved to be good as a device that can save a person’s life.
Also, one should not forget about basic safety measures during operation. If a fire occurs with electrical equipment, only carbon dioxide and powder fire extinguishers can be used. The second ones show the best result in the fight against fire, but equipment dusted with dust can not always be restored.
Conclusion
Using examples that are clear to every reader, we have found that the ordered directional movement of charged particles is called electric current. This is a very interesting phenomenon, important from the standpoint of both physics and chemistry. Electric current is a tireless assistant to man. However, you need to handle it carefully. The article addresses security issues that should be addressed if there is no desire to die.