When you hear an ambulance, police car or other special vehicles that use the siren, you ever notice how it changes the sound of the sirens? As we approach the sound becomes higher, and as the distance of his tone is markedly reduced, is not it? What you hear is the result of shifting the frequency of the sound waves around a particular object, more broadly, this phenomenon known as the Doppler effect, and the name it received after the Austrian mathematician and physicist Christian Doppler (Christian Doppler) was first discovered this principle in the middle 1800s.
When something moves toward you, the sound waves "bunch up", thus due to compression wave step increases. When an object passes you and starts to move away, the waves begin to expand, and the sound in the meantime become more muted and low.
The word "Doppler" is often reminiscent of the expression "Doppler Radar", a term that is often used when talking about meteorology. Most meteorologists rely on the Doppler radar system to get accurate results about the time of arrival of rain and its orientation. The Doppler effect is a part of this process. The radar system uses a powerful antenna to send pulses of radio waves. The required number of pulses catches in the upper atmosphere conditions to rain and back to the source with accurate data.
Have you ever wondered how such heavy objects as, for example, the aircraft may be in the air? On this issue, you can quickly find the answer if you're familiar with the Bernoulli principle. Opened in the 1700s, Swiss physicist and mathematician Daniel Bernoulli (Daniel Bernoulli), the law of physics states that the pressure of liquid or gas decreases with increasing speed.
But what is there to do with airplanes? The shape of the wing in the dissection of the air creates a lower pressure above the wing than under it. It is this pressure difference and helps the plane to take off and stay in the air. The faster the wing, the greater the lift force created while the plane climbs higher and higher.
Classic state veschestva
Everyone knows that the substance is in three forms: solid, liquid and gaseous. Although some scholars argue that the plasma is also to be seen everywhere, as a rule, they use these three options.
Each of them to determine the physical characteristics that largely depend on the kinetic energy of the molecules, that separates them from each other, as well as the attractive force that pulls them together. The temperature and energy is determined by what kind of force would win. The higher the temperature of the molecules, the more kinetic energy is produced, and the faster they move.
You can see this in action, watching the ice cubes in a glass, which is a solid state when the molecules are vibrating position. When the ice melts, the molecules gain enough kinetic energy to overcome the force until the ice has melted completely.
When boiling water, the molecules are extremely energetic and kinetic energy is much greater than the force of attraction between them. Thus, the water becomes a gas and extends beyond the container in which it is contained. Eventually, the water will evaporate.
The phrase "opposites attract" is often used when discussing the social relations, but its roots are purely scientific, and are directly related to the concept of magnetism. Observation and recognition of the existence of these forces took place over many centuries. However, most often the discovery of magnetism in 1600 attributed to the doctor and scientist William Gilbert (William Gilbert).
Magnetism - is the force that occurs when materials attract or repel other materials at a distance. The most common example of this phenomenon appears magnet on your refrigerator. The magnet has a strong magnetic field, so it attracts the iron, which is present in the door of your refrigerator. At the magnet has two poles (north and south), where he will be attracted to the opposite pole of another magnet and repelled by the same pole. The magnet will not stick on the refrigerator door, made of stainless steel because it contains nickel in various proportions, which usually covers the iron atoms.
How is it possible that the wind can blow on a curved trajectory or counterclockwise? Scientific explanations leave traces in a mathematical equation, tells about the Coriolis force, and as you can imagine, it is a little more complex than 1 +1 = 2. First discovered in 1835 by the French scientist Gustave-Gaspard Coriolis (Gustave-Gaspard Coriolis), it shows that objects moving within a rotating coordinate system, in fact, do not deviate from its path, but just seems to make it iz the change of coordinates.
Here is an explanation of a hit to the point as soon as the air begins to blow, and the observed pressure of different levels, the Earth rotates under it, and acts as an object or a rotating frame of reference. However, the movement on its surface, and a wind can not take place without acceleration. At the equator, the Coriolis force is zero in the northern hemisphere the wind "turns" to the right of the direction of their movement, and in the southern hemisphere, he "turns" to the left, making the Coriolis force that with which to be reckoned with when it comes to analyzing the storms and ocean currents .
What rises to the top, be sure to drop. Always. So said Sir Isaac Newton, a handyman, mathematician, astronomer, physicist and alchemist. Although there is a beautiful story about the fall of an apple on Newton's head, which led to his discovery of gravity. However, the authenticity of the story is still disputed.
As a result, he concluded that gravity - is a force that attracts all objects to the ground, resulting in all of them fall at the same speed, regardless of weight. However, gravitational forces may vary depending on the impact on other celestial bodies. On Earth, the force is always equal to the weight of the object, as opposed to the Moon, where gravity is about 1/6 of the weight (this explains the fact that the astronauts must always be tied to the lunar surface when walked on).
It turns out that Sir Isaac Newton knew something about the properties of light, as he was the first to realize that sunlight is actually made up of the whole range of colors, which in combination give white.
These colors in all its glory can be seen during this natural phenomenon, like a rainbow, as it is the case that comes in refraction. When light passes through a transparent material, in this case, raindrops, its speed is slowed down, as a result we see bend. The bending angle is slightly different wavelength, which leads to the identification of bright colors, of which actually consists light.
You do not need to be inside or outside the greenhouse in order to witness the greenhouse effect. In fact, the greenhouse in its physical manifestation has nothing to do with the very principle. The concept can be seen in practice a much closer distance, for example, when your car is heated sufficiently as a result of cold weather "capture" solar energy.
The term "greenhouse effect" is used to describe the temperature increase that occurs during the addition, as atmospheric gases (or greenhouse gases), such as water vapor, carbon dioxide or methane catch solar energy. On the large-scale level of the phrase is often used in discussions related to the Earth as a whole. In this case, we mean excessive exposure to sunlight on the planet's surface, resulting in the "re-emission" them back into the atmosphere.
However, not much of this heat is now actually returned to the atmosphere as it is returned due to human activities such as driving a car and deforestation, which causes the production of large amounts of greenhouse gases in the atmosphere.
It is called static for the following reason: this type of power is not moved over the wire, and accumulates on the surface of objects that are in contact with other objects it easily passes. Typically, in this process show a school using a balloon, which rub against the fabric.
Of course, this is not something with which face in practice most people, but the principle can be seen, for example, when you touch the door handle, and struck. In this case, static electricity is a motion of the electrons that have fallen to the carpet on your body, thus "armed" you additional charge of electrons, in which you and get a negative static charge.
Without the help of the refrigerator or any other device for cooling your drink quickly become warm.
In fact, the principle of averaging said energy by the movement of molecules. In the truest sense, however, the entropy measures the problems within the system that can not keep aloof.
In the case of a drink, for example lemonade "problems" within the glass bottle increases as fluid heating to room temperature, and the molecular motion of the bottle into the surrounding air also decreases due to exposure to heat.
The term "entropy" is often mistakenly used in discussions of decay, which, as a rule, the true culprits are bacteria.