What is the principle of thermal expansion and cold contraction? What is the principle of thermal ex

Thermal expansion and contraction An object expands when it is heated and contracts when it is cold. This is due to the fact that the motion of particles (atoms) in an object changes with temperature, and 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 properties of general objects, but substances such as water (0°C), antimony, bismuth, gallium, and bronze contract when heated in certain temperature ranges and expand when cold, which is the opposite of the properties of general objects. Therefore, when water freezes, ice appears first on the surface of the water.

For general objects, thermal expansion and contraction are established, mainly due to the increase in temperature, the kinetic energy of molecules, and the increase in the average free path of molecules, so it is manifested as thermal expansion and contraction, but there are exceptions, such as water, which is not to say that thermal expansion and cold contraction are not valid for water! Rather, there are hydrogen bonds in the water, and when the temperature drops, the number of hydrogen bonds in the water increases, causing the volume to increase as the temperature drops!

In life, we often feel the phenomenon of thermal expansion and cold contraction, such as the rupture of water pipes in winter and the inability to pump too much bicycle in summer, so how to intuitively observe the phenomenon of thermal expansion and cold contraction.

When the temperature is high, the molecules move fast! But different molecules change in size!

The non-harmonic effect of atomic vibration on the surface of the object (caused by the non-negligible term after the second order of Taylor).

Physics of Materials.

Thermal expansion and contraction is the property of an object that expands when it is heated and contracts when it is 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 general, when the temperature of an object increases, the volume of the object expands, the density decreases, and vice versa. This is commonly referred to as the phenomenon of "thermal expansion and cold contraction".

The principle of thermal expansion and contraction: because the motion of atoms in an object changes with temperature, when the temperature rises, the vibration amplitude of the atoms increases, causing the object to expand; But when the temperature drops, the amplitude of the vibrations of the atoms decreases, causing the object to shrink.

According to the smallest atomic structure of matter particles, the thermal expansion and contraction of matter should be formed by the accelerated internal motion of the atoms of matter. In terms of the internal structure of the atom, when the atom is heated, the protons and neutrons in the nucleus and the electrons outside the nucleus show an accelerated state of particle motion. First of all, due to the rotation of the nucleus and the action of the electric field, the electrons outside the nucleus are pulled to make a rpm around the nucleus.

The rotation speed of the nucleus determines the change of the centrifugal force of the peripheral electrons, which also determines the distance between the inner core and the orbit of the electron sphere and the level of the electric field. Only when the spin of the nucleus and the revolution of the outer electrons are excited by external energy will the centrifugal force and the electric field force change inside the atom, thus reflecting the natural phenomenon of thermal expansion and cold contraction of matter.

Thermal expansion and contraction refers to the phenomenon that the volume of an object increases at the heating temperature, expands, and the exothermic temperature decreases. It is determined by the motion of particles in matter and the spatial accumulation structure of particles, when the temperature rises, the amplitude of molecular or atomic vibration increases, so that the volume expands, and on the contrary, the volume decreases. In previous articles, water is an abnormally expanding substance, mainly between 0 and 4 degrees Celsius, and as the temperature increases, the spatial accumulation of water molecules becomes more compact, so the volume decreases.

Common phenomena and applications in life, 1After the egg is cooked, if it is cooled in cold water, the egg shell and the egg white are not easy to stick, because the eggshell and the egg white shrink to the same degree of cold and hot contraction, so there is a gap, which is easier to peel.

2.The cans that are bought back often have to use a lot of force to open, this is because when the cans are sealed, the hot air enters the inside, when the temperature drops, the volume shrinks, and the outside atmospheric pressure is stronger than the pressure of the internal can gas, so it is not easy to open the cap, if we heat the cans a little, it can be easily opened.

3.When building roads, in order to avoid road festering caused by the expansion and extrusion of high-temperature roads in summer and the contraction and stretching of low-temperature roads in winter, a gap is left every other distance, so as to reduce excessive concentration of force, prolong the service life of the road, and ensure everyone's travel safety.

In life, we often feel the phenomenon of thermal expansion and cold contraction, such as the rupture of water pipes in winter and the inability to pump too much bicycle in summer, so how to intuitively observe the phenomenon of thermal expansion and cold contraction.

Thermal expansion and contraction is a basic property of an object, in the general state, the object will expand after being heated, and it will shrink in the cold state. Most objects have this property.

There are many phenomena of thermal expansion and cold contraction in life.

Thermal expansion and contraction: The volume of the object becomes larger when heated, and the volume decreases when the temperature of the object decreases.

The principle of thermal expansion and contraction can be explained by the theory of molecular motion.

Thermal expansion and contraction, why does thermal expansion and cold contraction, and what is its principle?

In our lives, there are countless examples of thermal expansion and contraction of objects, but not all objects are thermally expanded and contracted. For example, in the summer, we can put the beer in the freezer of the refrigerator in order to chill it quickly, but if it is too long, the beer bottle will burst. This is due not only to the cold shrinkage of the glass bottles, but also to the expansion of the volume of the water in the beer after freezing.

This is the opposite of how to explain the expansion of water when it is heated and expanded?

There are a few substances in nature that have a very strange temperament, they are not thermal expansion and cold contraction, but heat contraction and cold expansion, also called abnormal expansion. 4 The following waters have this extraordinary property. Water at 4 has the highest density and the smallest volume.

As the temperature gradually drops, its volume gradually increases, and when it forms 0 ice, its volume expands instead of shrinking, and it is about one-tenth larger than before.

Due to the highest density of water in 4, a thick layer of ice forms on the surface of the river during the cold winter in the north, but the water temperature is always maintained at about 4 underneath the ice, which provides a good environment for aquatic life to survive.

Thermal expansion and cold contraction. The principle of the matter: The motion of particles or atoms within an object is affected by temperature and will change with the change of temperature.

When the temperature rises, the object is heated, and the vibration amplitude of the particles in the object 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 properties of objects in general, but substances such as water (below 4°C), antimony, bismuth, gallium and bronze exhibit the opposite properties.

Examples of thermal expansion and contraction

1. Soak the hard-boiled eggs in cold water, and the eggs will be easy to peel, because the shrinkage of the eggshell and egg whites is not the same.

2. The metal guardrail of the highway should always leave a gap at the joint, which is to prevent the guardrail from expanding and being damaged at high temperatures.

3. The rail is also to a certain length, there must always be a gap, and then extend downward, also because of the thermal expansion and contraction of the rail, if there is no gap, the rail will expand and bulge under the high temperature in summer.

4. When paving asphalt roads, there will be some gaps left in the next section of the road, which is to prevent the asphalt from expanding due to heat and expansion under the summer sun.

Thermal expansion and contraction is a phenomenon in which the volume of an object changes when the temperature changes, and the principle is that the intensity of the vibration of molecules or atoms inside the object changes due to the change in temperature, which in turn causes the volume change of the object.

1.Molecular Vibration and Temperature:

Temperature is a measure of the average degree of thermal motion of an object's molecules or atoms. When the temperature increases, the vibrations of the molecules or atoms inside the object intensify, and their average spacing also increases. This increase in molecular vibrations causes the volumetric expansion of the object, i.e., thermal expansion.

In construction, especially in the design of large buildings and bridges, the influence of thermal expansion and contraction on the structure needs to be considered to prevent damage caused by temperature changes. In industrial and manufacturing industries, it is critical to develop appropriate material choices and design schemes to cope with thermal expansion and contraction.

2.Thermal Expansion and Material Properties:

Different materials respond differently to temperature changes. Generally speaking, solid materials have the least thermal expansion, followed by liquids, and gases have the greatest thermal expansion. This is because the solid molecules are arranged in a relatively tight manner, so there is a limit to the volume change caused by the vibration of the molecules.

Whereas, the spacing between the molecules of a liquid is larger, so the thermal expansion of a liquid is greater than that of a solid.

3.coefficient of thermal expansion and contraction and linear thermal expansion:

The coefficient of linear thermal expansion is a physical quantity that describes the degree of linear thermal expansion of an object under temperature changes. It represents the amount of change in length of an object per unit length when the temperature increases by 1 degree. The coefficient of linear thermal expansion varies from substance to substance, which can be used to calculate the change in the volume of an object at different temperatures.

4.Applications & Engineering:

The principle of thermal expansion and cold contraction has a wide range of applications in engineering and science. For example, gaps in rail-laying leave room for rails to expand and contract during thermal expansion and contraction. In construction, especially in the design of large buildings and bridges, the influence of thermal expansion and contraction on the structure needs to be considered to prevent damage caused by temperature changes.

In industrial and manufacturing industries, it is critical to develop appropriate material selection and design solutions to cope with thermal expansion and contraction.