Thermal Expansion of Solids, Liquids and Gases.

The change in temperature of a body causes the expansion or contraction of that body, depending on the temperature. When heated, most of the chemicals expand and when cooled, they shrink. Thermal expansion of solids, liquids and gases is used to describe this phenomenon. After being placed upside down in hot water for some time, it has been noticed that bottles with a metallic lid that is well-sealed are readily opened when the bottle is turned upside down again such that just the lid is submerged in hot water. The steel lid stretches and opens effortlessly as a result of this. When a thermometer is submerged in warm water, the amount of mercury increases and when the thermometer is removed from the water, the mercury level falls.

Thermal expansion of gases

When a balloon is half inflated in a chilly environment, it expands to its full size when submerged in warm water. This is true in the case of gases. The thermal expansion of gases is responsible for all of this.

As a result, the thermal expansion of gases is defined as a rise in the size of a body due to an increase in temperature. Linear expansion is the term used to describe the increase in length. The term “area expansion” refers to expanding a geographical region. Volume expansion is the term used to describe the increase in volume. The coefficient of thermal expansion of gases quantifies the fractional change in size that occurs due to a minor increase or decrease in temperature.

Metals expand more than other materials and have rather high linear expansion coefficients. Known as the coefficient of volume expansion, the fractional change in the volume of a material caused by a change in temperature is measured.

Thermal expansion of liquids

When it comes to thermal expansion of liquids, behave predictably. The heat between 0 degrees Celsius and 4 degrees Celsius causes it to shrink. When the thermal expansion of liquids is cooled from room temperature to 4 degrees Celsius, the volume of the water drops according to the reduction in temperature. When the temperature is below 4 degrees Celsius, the volume rises and the density falls.

This indicates that at 4 degrees Celsius, the density of water reaches its maximum. Because of this feature, water bodies such as lakes and ponds freeze near the top of the water column.

The thermal expansion of gases is greater than the expansion of solids and liquids at room temperature. The coefficient of gas expansion is proportional to the temperature of the gas. The ideal gas equation may be used to calculate the coefficient of volume expansion at constant pressure for an ideal gas. 

For example, for an ideal gas, at 0 °C, αv = 3.7 × 10-3 K–1, which is much larger than that for solids and liquids.

A relationship may be established between the volume expansion coefficient and the linear expansion coefficient. To prevent the thermal expansion from occurring, it is necessary to fix the rod’s ends securely. If this is done, the rod will experience compressive strain due to external forces generated by the rigid support at the ends. Thermal stress is the term used to describe the stress created in the rod as a result of this tension.

Thermal expansion of solids

The thermal expansion of solids is represented as a change in the solid’s height, thickness and length. While the volumetric expansion coefficient is more beneficial for the thermal expansion of liquids than the thermal expansion of gases, it is less useful for solids. We can calculate the volume change (liquid or gas) in general terms if the substance is a fluid (liquid or gas).

Thermal expansions of solids, liquids and gases have a variety of applications.

Thermal expansions of solids, liquids and gases are used in various applications, some of which are listed below. 

1. Thermal expansion is a measurement technique used in thermometers to determine the temperature.

2. Thermal expansion is used to loosen the grip on tight-fitting lids.

3. If your window has a metal frame, you’ll need to use rubber spacers.

Thermal expansion of solids, liquids and gases.

When the matter is heated, it expands in all three states: solid, liquid and gas. The atoms themselves do not grow, but the amount of space they occupy does so.

During the thermal expansion of solids, the atoms in the solid vibrate more rapidly about their fixed positions. Consequently, the percentage increase in the size of solids when heated is minor compared to other processes. To not bend when heated by the sun, metal railway tracks are designed with tiny gaps between the rails. Since the links between individual molecules in liquids are often less tight than those in solids, thermal expansion of liquid is more than solids for the same reason as solids. A thermometer that measures liquid in a glass is based on this idea. When the temperature of the liquid rises, the liquid expands, causing it to climb up the side of the glass.

Molecular distances inside gases are greater and molecules are very faintly attracted. Because of heat, molecules move more quickly (heat energy is transformed to kinetic energy), which implies that the volume of gas expands much more than the volume of an inert solid or liquid.

Conclusion

The kinetic particle theory is a physical theory that describes the characteristics of the thermal expansion of solids, liquids and gases in motion. When a shift in state occurs, there are energy changes that occur. Brownian motion is defined as the random movement of fluid particles in a fluid medium. Gases trapped inside a defined volume, on the other hand, are unable to expand and as a consequence, rises in temperature result in pressure increases.