Coefficient of performance (COP) is a measure of the effectiveness of any system, be it a car engine, car or other mechanism. It shows how efficiently the system uses the received energy. To calculate efficiency very easily.

Density is a physical quantity, through which objects with the same mass can have different volumes. For density measurement uses standard units adopted in the SI system.

In the course of a reaction some substances are transformed into others while changing its composition. Thus, the "source concentration"is the concentration of substances prior to the occurrence of a chemical reaction, that is, converting them into other substances. Of course, this transformation is accompanied by a decrease in their number. Accordingly, it reduced the concentration of the starting materials, until a zero value if the reaction has proceeded to the end, irreversibly, and the components were taken in equal amounts.

Beautiful poetic expression "wind rose" is called a strict heraldic symbol-an octagon – the symbol of perfection and the desire for wonderful, romance of distant wanderings. And in fact is a rigorous mathematical diagram.

Vapor pressure is one of the characteristics of various liquids and has been cited as a reference in the literature. Knowledge of this quantity allows by changing the external pressure to encourage the fluid to boil or, conversely, to form a condensate from the gaseous product.

To determine the relative humidity of the air learn real pressure or density of vapor at a given temperature, divide the value of the pressure of saturated steam at a given temperature, which can be found in the table and multiply by 100%. The relative humidity of the air can be found depending on the difference in the readings of dry and wet thermometers or change the length of the hair depending on the humidity.

Hair grows on human skin and represent the Horny formation of elongated cylindrical shape. They cover almost the whole body surface except the soles of the feet, hands, bends of limbs, lips.

Transformers is known for more than 100 years and are an integral part of transmission lines are widely used in electronic equipment and various household appliances. It is thanks to the effect of transformation is possible to obtain an electric current with the required parameters.

The momentum of the body is otherwise called the amount of traffic. It is determined by the product of mass and velocity. It can also be found through the duration of the force on the body. The physical meaning is not the impetus to change.

Molar concentration is the value which indicates how many moles of the substance is 1-m liter of solution. For example, it is known that in a liter of solution is exactly of 58.5 grams of common salt – chloride of sodium. Molar because this substance is 58,5 g/mol, we can say that in this case you have odnokolernyh salt solution. (Or, in record, 1M solution).

The choice of method of inclusion of a rheostat in the circuit is connected, as a rule, with the purpose of the resistor in a particular circuit. Therefore, it is necessary to understand the concept of a device that is used.

Concentration is the value which characterizes the quantitative composition of the solution. According to the rules of IUPAC solute concentration is the ratio of the mass of the dissolved substance, or its quantity to the volume of the solution (g/l, mol/g), i.e. the ratio of the inhomogeneous quantities. Sometimes it is necessary to prepare a solution of specified concentration. How to do it?

The light waves are deflected from their straight path when passing through small openings or past of small obstacles. This phenomenon occurs when the dimensions of obstacles or openings comparable to the wavelength, is called diffraction. Challenges in the determination of the deflection angle of light is necessary to solve most often applied to the diffraction lattice surface in which alternate transparent and opaque areas of equal size.

Molar mass is the mass of one mole of a substance, i.e. the value showing what quantity of a substance contains 6,022*10 (in degree 23) of particles (atoms, molecules, ions). But if we are not talking about pure substance and mixtures of substances? For instance, vital to people the air, because it represent a mixture of a great many of gases. How to calculate its molar mass?

Ozone is one of the variants (modifications) of oxygen, with the chemical formula O3. Under normal conditions represents a gas of blue color and with sharp characteristic odor. If it is subjected to liquefaction, takes a deep blue colour. The first mention of ozone refer to 1785. Ozone is a very unstable compound and rapidly converted to diatomic oxygen. The higher the temperature and lower the pressure, the faster is the transition. How can I get ozone?

The flora is varied and beautiful. When we think or talk about nature, to mind immediately comes an abundance of rich green grass and bursting with oxygen the trees have green foliage. And why are leaves green?

Emerald – a precious stone of a high class. Some samples of emeralds can cost more than diamond. You can meet emerald in the most exquisite jewelry. Did you know that emerald can be grown at home?

Amber is one of the most respected human stones, known since time immemorial. Fashion it still fails. Often there are imitations and fake amber, so it is advisable to buy jewelry made from this stone from trusted and reliable vendors. It will also be useful the ability to determine real amber.

The movement in real conditions can't continue indefinitely. The reason for this is the force of friction. It occurs upon contact of a body with other bodies, and always directed opposite to the direction of movement. This means that the force of friction always does negative work, what to consider in the calculations.

Letter λ (lambda) is the wavelength of a radiation. This value can be measured, can be calculated theoretically, and if the radiation is visible, even to define the eye.

The Volga river – great Russian river, has long become a symbol of Russia. She is depicted on the canvases of artists, its greatness is not just glorified in songs and poems. When you hear the name of this river, imagination immediately draws a picture of the vast water expanses. But in the upper Volga is only a small trickle.

Exhaustion is the pressure below atmospheric, the vacuum - deep exhaustion. To measure the vacuum applied to the devices operating on different physical principles.

Between amperage and voltage there is directly proportional dependence described by Ohm's law. This law defines the relationship of current, voltage and resistance at the area of electrical circuits.

Pressure is an important physical quantity that characterizes the behavior of liquid and gaseous substances. Is called the absolute pressure, measured relative to the temperature equal to absolute zero. Such pressure creates the ideal gas on the vessel wall.

Solid - liquid and there is no paradox. Yes, indeed, there are substances which, even in the solid state behave like liquids. On the other hand, in ordinary life, few men were met by a substance harder than glass.

Humidity measurement is necessary as physicists and weathermen. And ourselves this question, too, should be interested in, especially if we sit for a long time in the same room. Because humidity affects the human body because we need to control. There are two main types of instruments for measuring humidity. They differ in the device and principle of work. It hygrometers and psychrometers.

Reduplication is the doubling of the DNA helix that occurs in the process of cell division. The DNA is in the nucleus, and after it split in two, starts all other processes that accompany cell division.

Rainbow is one of those unusual optical phenomena, which nature sometimes delights the person. Since ancient times, people have tried to explain the appearance of the rainbow. Science is a significant step closer to understanding the process of the emergence phenomenon when in the middle of XVII century the Czech scientist mark Marci found that the light beam is inhomogeneous in their structure. Later Isaac Newton have studied and explained the phenomenon of dispersion of light waves. As we now know, the light ray is refracted at the boundary of two transparent media with different density.

Fats or lipids are organic compounds. Their main components are triglycerides, which in common parlance is often referred to as the fat and lipid materials (phospholipids, sterols, etc.). Fats can be of vegetable and of animal origin.

The sun star Solar system, around which revolve all of its planets. In comparison with the Earth size and mass of the Sun can without exaggeration be called a tremendous.