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Instructions

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Fluctuating weather with a significant changeTemperature regimes, when the differences are more than 8 degrees Celsius during one day, negatively affect people with unstable blood pressure.

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With a significant increase in temperature, the vesselssharply expand, so that the blood circulates faster and cools the body. The heart starts to beat much more often. All this leads to a sharp change in blood pressure. In hypertensive patients with insufficient compensation of the disease, a sharp jump can occur, which will lead to an hypertensive crisis.

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Hypotonics with an increase in air temperatureFeel dizzy, but at the same time the heart rate becomes significantly faster, which somewhat improves the state of health, especially if hypotension occurs against the background of a bradycardia.

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Reduction of air temperature leads to narrowingBlood vessels, the pressure is somewhat reduced, but against this background there may be a severe headache, since narrowing of the vessels can lead to spasm. With hypotension, blood pressure may drop to critical levels.

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As the weather becomes stable,The autonomic nervous system adapts to the temperature regime, the state of health stabilizes in persons who do not have serious deviations in their health status.

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Patients with chronic diseases with strongdifferences in air temperature and atmospheric pressure should be particularly careful to monitor their health, more often to measure blood pressure with a tonometer, take medication prescribed by a doctor. If the usual dose of pharmaceuticals is still observed unstable blood pressure, you need to see a doctor for a review of treatment tactics or changing the dosage of prescribed drugs.

Instructions

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A very close relationship can be found betweenfluid temperature and atmospheric pressure. Inside any liquid, there are many small air bubbles that have their own internal pressure. When heated in these bubbles, saturated vapor evaporates from the surrounding liquid. All this continues until the internal pressure becomes equal to the external (atmospheric) pressure. Then the bubbles can not stand and burst - there is a process called boiling.

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A similar process occurs in solidsAt melting or at the return process - crystallization. A solid body consists of crystal lattices, which can be destroyed when atoms are separated from each other. The pressure, while increasing, acts in the opposite direction - presses the atoms to each other. Accordingly, in order for the body to melt, more energy is required and the temperature rises.

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The Clapeyron-Mendeleev equation describestemperature dependence on the pressure in the gas. The formula looks like this: PV = nRT. P is the gas pressure in the vessel. Since n and R are constants, it becomes clear that the pressure is directly proportional to temperature (for V = const). This means that the higher P, the higher t. This process is due to the fact that when heated, the intermolecular space increases, and the molecules begin to move rapidly in a chaotic order, which means that it is more often to hit the walls of the vessel in which the gas is located. The temperature in the Clapeyron-Mendeleev equation is usually measured in degrees Kelvin.

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There is the concept of standard temperature and pressure: the temperature is -273 ° Kelvin (or 0 ° C), and the pressure is 760 mmHg.

You will need

• A textbook on physics of grade 7, a textbook on molecular physics, a barometer.

Instructions

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Read in the textbook on physics class 7definition of the concept of pressure. Regardless of what type of pressure is considered, it is equal to the force acting on a single area. Thus, the greater the force acting on a certain area, the greater the pressure value. If we are talking about air pressure, then the force under consideration is the gravity of air particles.

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Please note that each layer of airIn the atmosphere creates its own contribution to the air pressure of the lower layers. It turns out that with an increase in the altitude above sea level, the number of layers that pressure the lower part of the atmosphere grows. Thus, with increasing distance to the earth, gravity increases, acting on the air in the lower parts of the atmosphere. This leads to the fact that the layer of air located at the surface of the earth experiences the pressure of all the upper layers, and the layer closer to the upper boundary of the atmosphere does not experience such pressure. Accordingly, the air in the lower layers of the atmosphere has a much higher pressure than the air in the upper layers.

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Remember how the fluid pressure depends ondepth of immersion in the liquid. The law describing this law is called Pascal's law. He claims that the fluid pressure increases linearly with increasing depth of immersion in it. Thus, the tendency of the pressure drop with increasing height is also observed in the liquid, if the height reading starts from the bottom of the tank.

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Note that the physical essence of the enhancementThe pressure in the liquid with increasing depth is the same as in air. The lower the layers of liquid lie, the more they must retain the weight of the upper layers. Therefore, in the lower layers of the liquid, the pressure is greater than in the upper layers. However, if the regularity of pressure increase in the liquid is linear, then in the air it is not so. This is justified by the fact that the liquid does not contract. The compressibility of air leads to the fact that the pressure dependence on the lift height above sea level becomes exponential.

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Remember from the course of the molecular-kinetictheory of an ideal gas, that such an exponential dependence is inherent in the distribution of the particle density with the gravitational field of the Earth, which was revealed by Boltzmann. Boltzmann distribution, in fact, is directly related to the phenomenon of air pressure decay, because this decline leads to the fact that the concentration of particles with altitude decreases.

Atmospheric pressure may vary duringDays. Its indicators also depend on the season. But, as a rule, such pressure jumps occur within no more than twenty to thirty millimeters of mercury.

Such fluctuations are not noticeable for the organismhealthy person. But here, in individuals suffering from hypertension, rheumatism and other diseases, these changes can cause disturbances in the functioning of the body and worsen overall well-being.

Reduced atmospheric pressure a person canFeel when you are on the mountain and take off on the plane. The main physiological factor of height is the lowered atmospheric pressure and, as a result, the reduced partial pressure of oxygen.

The body reacts to a decreased atmosphericFirst of all, by increased breathing. Oxygen at altitude is discharged. This causes excitation of the carotid chemoreceptors, and it is transmitted to the medulla oblongata to the center, which is responsible for the enhancement of respiration. Thanks to this process, the pulmonary ventilation of a person who experiences reduced atmospheric pressure rises within the required limits and the body receives a sufficient amount of oxygen.

An important physiological mechanism thatIt starts at a lowered atmospheric pressure, it is considered that the activity of organs responsible for hematopoiesis is strengthened. This mechanism appears in the increase in the amount of hemoglobin and red blood cells in the blood. In this mode, the body is able to transport more oxygen.

You will need

• - the flask;
• - the test liquid;
• - cork or rubber cork;
• - laboratory thermometer;
• - Curved tube.

Instructions

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As the simplest device for determining the temperature Boiling You can use a flask with a capacity of about 250-500Milliliters with a round bottom and a wide throat. In it, pour the test fluid (preferably within 20-25% of the volume of the vessel), plug the neck with a cortical or rubber stopper with two holes. In one of the holes, insert a long laboratory thermometer, into the other - a curved tube that plays the role of a safety valve for the evacuation of vapors.

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If it is to be determined Temperature Boiling clean liquid - the tip of the thermometer should be near it, but not touching it. If it is necessary to measure Temperature Boiling Solution - the tip should be in the liquid.

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With what heat source can be heateda flask with a liquid? It can be a water or sand bath, an electric stove, a gas burner. The choice depends on the properties of the liquid and the expected temperature of its Boiling.

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Immediately after the process begins Boiling, write down Temperature, Which shows the mercury column of the thermometer. Monitor the thermometer for at least 15 minutes, recording the readings every few minutes at regular intervals. For example, measurements were taken immediately after the 1st, 3rd, 5th, 7th, 9th, 11th, 13th and 15th minutes of the experiment. In total, there were 8. After completing the experiment, calculate the arithmetic mean Temperature Boiling by the formula: tcp = (t1 + t2 + ... + t8) / 8.

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It is necessary to take into account a very important point. In all physical, chemical, technical reference books, temperature Boiling fluids are given under normal atmospheric conditions.pressure (760 mm Hg). From this it follows that simultaneously with the measurement of temperature it is necessary to measure the atmospheric pressure with the help of a barometer and to make the necessary correction in the calculations. Precisely the same corrections are given in the temperature tables Boiling For a variety of liquids.