Does the ambient temperature change after the wet gauze freezes? Physics in the second year of junio

A: Xiao Wang's guess is correct.

In the change of state of matter, the vaporization should absorb heat, and the surrounding temperature should be reduced, and when the temperature around the leakage hole is lower than zero, the cotton yarn will freeze.

In fact, it is very easy to think that the wet cotton yarn should be frozen, obviously below the freezing point of the water.

Xiao Wang's mother: Yes.

The freezing of the damp veil is due to the fact that the liquefied petroleum gas absorbs a large amount of heat when it vaporizes sharply, absorbing the heat of the water inside the damp veil, causing the water to solidify and freeze.

However, this phenomenon only sounds near a damp veil and does not affect the surrounding air temperature, so the surrounding temperature should still be around 20.

That's right! That's right! Liquefied gas absorbs a lot of heat during vaporization, causing the temperature in the vicinity to drop, which is why the phenomenon of freezing occurs. However, this cooling is only on a local scale and will not affect the temperature at longer distances.

1.Xiao Wang. Because the leaked liquefied petroleum gas vaporized sharply, the vaporization absorbed heat to cool and cool, and when the firefighters used the wet cotton yarn, the cotton yarn also froze.

2.The liquefied petroleum near the leak hole is rapidly vaporized when it encounters high temperature gas, and the vaporization absorbs heat to cool down and refrigerate, so that the water in the moist cotton yarn condenses into ice.

In the cold winter, if the "frozen pear" that has been frozen outside is retrieved and placed in a large basin of water at 0 degrees Celsius, the possible phenomenon is that part of the water in pot B freezes and the temperature of the pear rises.

A part of the water in the basin freezes and lowers the temperature of the water.

A part of the water in pot b freezes and the temperature of the pears rises.

A part of the water in the C pot freezes, and the frozen pears remain unchanged.

d frozen pears are always below 0

Frozen pears have a low temperature and can absorb heat from the water. A part of the water in the basin is exothermic and solidified.

The answer is b, because frozen pears have a low temperature and can absorb heat from the water. A part of the water in the basin is exothermic and solidified.

Since the temperature difference of 100 is expressed as 90 in this thermometer, and the beginning of 0 is -6, [21-(-6)] = 30

In the same way, the actual temperature of hot water can be calculated as -6 + 60 = 48 Since the change of the liquid column is proportional to the temperature difference, the difference in temperature is 4 The difference in temperature of the liquid column is 1cm, then the temperature of the liquid is 0 + 15-3) 4 = 48

In the same way, at 25 the length of the liquid column is 3 + 25 4 = cm

Analysis: First, a normal thermometer, which is shown as 0 in ice-water mixture, and 100 in boiling water, is divided into 100 scales.

That is, each cell represents the temperature as: (100 -0) 100 cells = 1.

The thermometer in this problem is shown as 4 in the ice-water mixture and 98 in boiling water, i.e. there are 94 squares, but the real temperature represented should also be 100. That is, each grid represents a temperature of:

100 -0 ) 94 grid = 50 47.

Solution: The thermometer is shown as 4 in ice-water mixture, and the number is 98 in boiling water, i.e. 100 is represented by 94 grids.

Then the temperature represented by each grid is:

to=(100 -0) 94 grids = 50 47.

When it is displayed as 51, there are 47 bars between it and the ice-water mixture reading 4, then the true temperature is:

t=50/47℃×

Got it? If you understand, you'll get extra points, hehe.

Zero degrees The ice-water mixture is 0 degrees. The way it works is to take a piece of ice and sink it to the bottom of the lake, and a day later you see if the ice is still at the bottom of the lake. If the temperature at the bottom of the lake is also zero, if there is no hot spring under the --- lake, it can be exploited.

I don't understand the explanation of this question, the temperature of the water under the ice, how deep the water temperature is, just take a thermometer to measure it......This question.

There is also a lake because it is not pure, its freezing point is not zero, and the surface and bottom temperatures are different......

No matter what the temperature, there are always some molecules in the liquid with a high velocity that can fly out of the liquid surface and become vapor molecules, so the liquid can evaporate at any temperature. If the temperature of the liquid increases, the average kinetic energy of the molecules increases, and the number of molecules flying out of the liquid surface increases, so the higher the temperature of the liquid, the faster the evaporation;

Blowing air from the wind on the surface of the garment can speed up the evaporation of water, evaporation and heat absorption, combined with heat from all over the surrounding area, can dry the garment, but the process is slow.

I don't know if it's right, I'm a sophomore in junior high school, and I'm a good student in physics. Ho ho,

Cold winter, hanging in the room.

Wet clothes outside can freeze Even though the outside temperature is always below zero, frozen clothes will eventually dry out due to ice sublimation.

For the sake of sublimation

To solve this problem, you should know that the process of matter directly changing from a solid state to a gaseous state is called sublimation, and it needs to absorb heat during sublimation Answer: Solution: Solid ice can be turned into water vapor between them, and sublimation occurs, so frozen clothes will eventually become dry;

Therefore, the answer is: sublimation Comments: To solve such problems, we should analyze and answer them in combination with the sublimation phenomenon in life

And it has to be faster

The freezing point of water is 0 degrees, which means that when the temperature of the water drops to 0 degrees, it will start to freeze; You know, there is a premise here, that is, the water in question is pure water, which is water that does not contain any impurities, such as distilled water. For example, if the sea contains a lot of salt (calcium chloride, magnesium chloride, etc.), then the freezing point of the sea water is below 0 degrees, so in the cold winter in the north, sometimes the sea water is not frozen, but its temperature is below 0 degrees. The river water is freshwater and contains very few soluble impurities, so its freezing point is basically 0 degrees.

It is important to note here that the so-called "freezing point" refers to the freezing temperature of the water, not to the air temperature, because for the temperature of the water to reach 0 degrees, the air temperature must be below 0 degrees. This is what we experienced, when the temperature has dropped to a few degrees below zero, the river is still not frozen; Why is that? This is because although the temperature is below 0 degrees, the river water has not yet dropped to 0 degrees, and only the low temperature continues until the temperature of the river drops to 0 degrees, and the river water begins to freeze.

The volume of the compressed LPG begins to expand after it is released, indicating that the gas molecules that were originally close to each other have received additional energy and begin to scatter in all directions. And this extra energy cannot be obtained out of thin air, but can only be obtained from the surrounding air molecules, which reduces the energy of the air molecules and slows them down, and the speed of the gas molecules is manifested as the temperature in reality, so that the surrounding temperature drops, which can make the wet gauze freeze!

In the case of liquefied gas, it absorbs a large amount of heat during vaporization, causing the water to freeze.

In the case of compressed natural gas, the positive Joule-Thomson effect occurs:

When a gas flows through a pipeline, its pressure drops significantly due to local resistance, such as when it encounters a necking and regulating valve, a phenomenon called throttling. In engineering, because when the gas passes through the flow resistance elements such as valves, the flow rate is large and the time is short, and it is too late to exchange heat with the outside world, so it can be approximately treated as an adiabatic process, which is called adiabatic throttling.

Experiments have found that the temperature before and after the actual gas throttling will generally change. The change in temperature of a gas during throttling is called the Joule Thomson effect (charred effect). The reason for this phenomenon is because the enthalpy of the actual gas is not only a function of temperature but also of pressure.

Most real gases have a cooling effect during throttling at room temperature, i.e., the temperature decreases after passing through the throttling element, and this temperature change is called the positive Joule Thomson effect. The temperature of a few gases rises after throttling at room temperature, and this temperature change is called the negative joule Thomson effect.

After the compressed LPG is released through the throttle valve, the temperature decreases due to the positive Joule Thomson effect, and the low temperature gas comes into contact with the water at room temperature on the moist gauze, absorbing its heat, causing the water to freeze.

For a specific mathematical explanation of the Joule Thomson effect, please refer to any physical chemistry textbook.

Since it is liquid, it absorbs a lot of heat when vaporized.

Ice works well.

In the process of melting into 0 degree water, the ice also attracts a lot of heat, causing the temperature of external objects to drop

(1) The volume of water freezing increases; (2) Burst water pipe; (3) Formulate hypotheses - design experiments - draw conclusions; Water freezing is exothermic and cold, thermal expansion and contraction, and the volume becomes smaller.

(1) The volume of water freezing increases; (2) Burst water pipe; (3) Formulate hypotheses - design experiments - draw conclusions; (4) The landlord thinks about one casually.

The volume becomes larger.

If the water pipe bursts, the cracks in the cultural relics will also be expanded, as will the cracks in the rocks, which will make mudslides more likely to occur.

Asking questions – formulating conjectures and hypotheses – designing experiments – collecting data --- analyzing experiments – drawing conclusions.

When is the largest volume of water of the same mass?

at four degrees Celsius).

1. Temperature is a measure of temperature, and the commonly used thermometer measures the temperature according to the nature of thermal expansion and contraction. When measuring the temperature, the temperature scale is usually used in degrees Celsius, which is usually based on the temperature of the ice-water mixture as zero degrees, and the boiling of water under the standard atmospheric pressure (i.e. one atmosphere) as 100 degrees, and divides between 0 degrees and 100 degrees into 100 equal parts, each equal part is called 1 degree Celsius. In the International System of Units, temperature is measured using the Fahrenheit scale, and the formula for its relationship with the aforementioned temperature scale is 32 degrees Fahrenheit

Degree of heat and cold Thermal expansion and contraction Celsius Freezing point of ice Boiling point of water 1 degree Celsius Kelvin Degree Kelvin = degree Celsius +