Why is it expanded by heat at the same time, the iron cover is larger than the glass

The expansion coefficient is a physical quantity that characterizes the thermal expansion properties of an object, that is, a physical quantity that characterizes the increase in length, area and volume of an object when it is heated. The increase in length is called "linear expansion", the increase in area is called "surface expansion", and the increase in volume is called "bulk expansion", which is generally called thermal expansion. When the temperature of an object per unit length, unit area and unit volume rises1, the changes in its length, area and volume are respectively called the linear expansion coefficient, the surface expansion coefficient and the bulk expansion coefficient, which are collectively called the expansion coefficient.

It is equivalent to the relative increase in the volume of the object at an increase in temperature of 1.

Since there is always internal energy, every particle of matter vibrates.

When matter is heated, the heat energy of each particle increases due to the increase in temperature, resulting in an increase in amplitude, and the distance between two atoms bound to each other by (non-harmonic) forces also increases, and the matter expands.

The thermal expansion of matter is caused by non-harmonic (nonlinear) vibrations.

For every 1 degree increase in iron temperature, the length or width or height of the size increases by 12x10 -6, that is, for every 1 degree increase in ordinary glass, the coefficient of linear expansion is about visible.

Different materials have different thermal expansion rates

This is the property of the material.

It's the same as resistance, specific heat capacity, and so on

The glass self-detonation main bai is the reason for the installation and du glass itself. The coefficient of thermal expansion of tempered glass.

The DAO is relatively high, if the version is installed over the right.

If there is not enough expansion space left in the process, it will cause the glass to expand and explode when heated.

In addition, the glass contains stones, bubbles and impurities, which are prone to cracks when these substances are not fully fused during the production process, and the glass contains nickel sulfide crystals, which are also prone to self-explosion when heated and expanded.

The glass will not be exposed to high temperatures, but the glass will suddenly cool when it is at high temperatures.

High temperatures do not necessarily cause the glass to burst, it is due to the fact that the glass itself is defective or heated and cooled at a very fast rate.

Ordinary glass rights will only be broken in the process of rapid heating, the reason is that the glass is a bad conductor of heat, in the rapid heating process, the uneven heat and cold of each part, due to the reason of thermal expansion and contraction, resulting in breaking, untreated glass, rashly poured into boiling water, will be broken is the reason. Therefore, ordinary glass will not be broken in summer, and no matter how strong the sun is, its heating process is relatively slow.

If the exposed glass suddenly encounters cold water, it may crack due to thermal expansion and contraction. In particular, if there are small cracks or small pits in the car glass, washing the car at high temperature is more likely to cause the glass to burst. In addition, most of the car window glass is now filmed, because the shrinkage ratio of film and glass is different, the glass will burst when washing the car at high temperatures.

Glass is a poor conductor and is fragile. When the temperature difference between the inside and outside of the glass is too large, and its internal and external expansion is inconsistent, bursting will occur.

Glass is chemically inert in everyday environments and does not interact with living organisms. Glass is generally insoluble in acids (exception: hydrofluoric acid reacts with glass to form SIF4, which leads to corrosion of glass); But soluble in strong bases, such as cesium hydroxide.

Because glass is less able to expand and contract when exposed to heat or cold, if the temperature changes suddenly, the glass will crack.

Glass is a poor conductor and is fragile. When the temperature difference between the inside and outside of the glassware is too large, the expansion inside and outside is inconsistent. For example, if boiling water is poured into a cold glass bottle, the circumference of the bottle will increase, but the temperature of the glass outside the bottle has not risen to the same level as that inside the bottle, so the outer circumference has not increased in time, so it is crushed by the glass inside the bottle.

Glassware that can withstand hot and cold should be selected with a small expansion rate, the thickness of the vessel should be small, and the shape of the vessel should not be too sharply curved.

When the heating is uneven, the degree of thermal expansion and contraction of each part of the glass is different, resulting in the deformation of the glass, and when the deformation reaches a certain level, it will explode.

Because glass does not conduct heat well. One place is hot and the other is relatively cold. Iron doesn't have anything to do with the structure of glass because it conducts heat well.

Because of thermal expansion and cold contraction, low temperature makes glass brittle, thermal expansion and cold contraction is the characteristic that the object will expand when heated and shrink when cold. Since the motion of particles (atoms) in an object changes with temperature, when the temperature rises, the vibration amplitude of the particles increases, causing the object to expand; However, when the temperature drops, the vibration amplitude of the particles decreases, causing the object to shrink.

Thermal expansion and contraction are the characteristics of general objects, but substances such as water (below 4°C), antimony, bismuth, gallium and bronze shrink when heated in certain temperature ranges, and expand when cold, which is the opposite of the characteristics of ordinary objects.

Therefore, when water freezes, ice appears first on the surface of the water. Due to the characteristics of thermal expansion and contraction of rails, a certain gap must be maintained when the rails are connected (to prevent the rails from being pushed and deformed due to thermal expansion and elongation when the temperature rises), and then the rails are connected with fishtail sheets and screws.

In this case, the temperature is lower, and the glass is more brittle, so it is easy to break. Good luck!

Fragile is to say that the toughness is poor. The toughness of metals, the microscopic principle of which is the existence of 'dislocations'. If the dislocation is easy to move, it can achieve greater deformation, that is, greater toughness.

The dislocations move to a certain extent, they will become intertwined, and it will be difficult to move. At the same time, if the force is to be realized, on the one hand, it is necessary to exert a large force (called the hardening of the material), and on the other hand, the toughness of the metal is reduced, and it breaks when it is pulled (entering the brittle stage).

The entanglement of dislocations can be eliminated by the process of 'climbing', which is a 'heat activated' process. That is, the higher the temperature, the later the entanglement will come, and the later the brittle stage will be.

In addition, at high temperatures, the atoms expand, and the interatomic forces will decrease, which is also conducive to the movement of dislocations. ）

The low temperature reduces the toughness of the glass, and the glass is slightly brittle, so it is easy to break.

Winter is not an instant change in temperature, and glass does not break. In winter, the large glass windows of the store are often broken, which has little to do with the low temperature. The main reason is that the bottom edge of the glass is uneven and the bottom pad material is not suitable during installation.

1. The glass partially overcomes gravity due to uneven distribution. The window sill is affected by the expansion of the ground and increases the local force of the glass again, and the force exceeds the limit of the internal stress of the glass, and the glass cracks. It is no problem for the glass to withstand dozens of degrees below zero, but it is estimated that the absolute zero degree will be broken, and the sudden cooling cannot exceed 30 degrees.

Ordinary glass has average heat resistance, and the temperature difference does not exceed 70 degrees, so it is not recommended to heat or cool quickly (put it in the refrigerator when it is hot). The tempered glass has a temperature difference of up to 135 degrees, and he can be tossed in theory, of course, in daily life. And due to the special properties of tempered glass, tempered glass has 2-3 times higher physical strength than general glass.

It is not easy to break, and it is suitable for children and the elderly or bar KTV to use. Heat-resistant glass is similar to tempered glass, and the temperature difference is also about 120 degrees. The biggest difference between the use process and tempered glass is that under normal use, heat-resistant glass will not self-detonate, but tempered glass will.

And even if both products explode during abnormal use, the tempered glass will have a splash, while the heat-resistant glass will not.

Ferric. Because the melting point is high.

The molecules move vigorously.

Because of the principle of thermal expansion and cold contraction, the glass is heated unevenly.

When the glass cup suddenly encounters hot water, the inner layer of the cup is heated and expands obviously, but the outer layer is not heated enough and expands less, so that the temperature difference between the parts of the glass is larger, and due to the reason of thermal expansion and cold contraction, the thermal expansion of each part of the glass is uneven, and when the uneven difference is too large, the glass may be broken.

The reason why the glass bursts is because of the swelling. As soon as hot water is poured into the cup, the inner wall of the cup is heated sharply.

It expanded, but the outer wall of the cup remained the same, and the inner glass suddenly squeezed outwards vigorously, and the cup broke. If you heat the inside and outside of the cup at the same time in advance, and then pour hot water, the degree of expansion between the inside and outside of the cup is not so large, and it will not burst. However, if the glass is very thin, even if hot water is poured into it, the heat will quickly spread to the outside, so that the inside and outside expand at the same time, and the cup will not break easily.

In addition, the so-called hard glass and heat-resistant glass, is the cause.

It is not easy to explode because the proportion of expansion is small.

Thermal expansion and cold contraction. You can pour less hot water first, shake it in the quilt, preheat the cup, and then pour hot water normally, and it won't fry.

First of all, the quality of this glass is not suitable for pouring boiling water, and then the hot water and cold air have a physical reaction, if you really want to use this cup to take hot water, you need to pour the hot water once the quilt is over, shake it, let the cup heat evenly, and then hot water, it will not be fried.

If the indoor temperature is high, pouring hot water will not burst, but when winter comes, the temperature drops, and due to the principle of thermal expansion and contraction, it is easy to explode in the cold season.

The inside and outside of the glass are unevenly hot and cold, and the coefficient of expansion is different, causing cracking.

The principle of thermal expansion and cold contraction. If a heated iron rod is suddenly placed on the glass bottle, the heated area will expand, and the unheated area will not expand. Because the glass bottle does not expand at the same time, it will break at the junction of hot and cold.