CBSE Class 11th Thermal Properties of Matter
 Matter in our universe is anything that occupies space and has mass. Practically, we are surrounded by matter. Right from a chair, we sit on the bottle of water or the bag carrying books. Everything matters. And matter has some properties by virtue of which every matter is different from the other and each of them can be identified. These properties include:

Mechanical Properties: These describe the material's physical characteristics, such as its ductility, plasticity, strength, and so on.

Chemical Properties: provide information about an object's composition, acidity or alkalinity, corrosive qualities, and other characteristics.

Physical Properties: It provides information about density, combustibility, conductivity, etc.

Dimensional Properties: These provide details about the matter's dimensions and form.The material's thermal properties indicate how it will respond to heat or variations in temperature.

What do Matter's Thermal Properties Mean?
As of right now, we understand that a substance's thermal characteristics determine its nature when exposed to heat or the reason it displays heat conductivity. Thus, as heat flows through an object, it exhibits its thermal qualities.Different materials or objects respond to heat in different ways according to their inherent thermal characteristics. Alternatively, these characteristics determine the matter's response to changes in temperature.

There are 4 major components of thermal properties. They are-

• Heat capacity

• Thermal Expansion

• Thermal conductivity

• Thermal stress

Let's take a closer look at these elements.

Heat Capacity: Heat capacity can be defined as the amount of heat required by the body to change its temperature by 1 degree. This amount of heat is expressed in Joules or calories and the temperature fluctuations or simply the temperature, is given in Celsius or Fahrenheit.

How to Calculate the Heat Capacity: The object's specific heat capacity is used to determine the heat capacity of an object with a given dimension.Q = m c ΔT is the formula that results from this.
here, 

1. Q is the heat capacity in J
2. m is the mass in g
3. c is the specific heat in J/kg.K
4. ΔT is the temperature change in °K

Thermal Expansion: When heat flows through an object, its initial shape is altered. To put it another way, heat causes a thing to expand. Thermal expansion is the property of substance or object that expands when heated. The objects' surface area, volume, and shape all alter as a result of thermal expansion.For gases, thermal expansion is noticeably considerable, while for liquids and solids, it is negligible.
Linear Expansion:  Linear expansion is the term used to describe a change brought about by thermal expansion that occurs in a single dimension or is unidimensional. It is provided by the                                                                                             ΔL = αLΔT

Whereas, ΔL is the length change L.ΔT is the temperature change.The coefficient of linear expansion, or α, is temperature-dependent.

Modes Of Heat Transfer
Three different modalities exist for the transport of heat across systems or between components of a system.

Conduction: When there is a temperature differential between two body parts, heat is transferred from one to the other.For example, when we place a rod in the flames and heat one end of it, the other end quickly becomes heated as well.

Convection: Here, heat is transferred as a result of matter motion, and this is only feasible for fluids.As an illustration, during the pumping and circulation of blood within the human body, heat produced by the body's cells is transmitted to the blood

Radiation: Here, the transfer of heat happens through electromagnetic waves.For example, the earth gets heated up by the direct rays of the sun falling on it. 

Thermal conductivity: The body undergoes some form of stress as a result of thermal expansion or contraction. We call this thermal stress. Thermal stress can occasionally be damaging because it has the ability to completely destroy an object. 
For example, you may have observed fractures appearing on the tires of large trucks. This is because hot tires are produced by friction between the road's surface and high speeds on the road. The tires break as a result of the ensuing heat stress.

FAQ-

Q1. What are the thermal properties of matter?
Ans. Thermal properties refer to the characteristics of a substance concerning its response to changes in temperature, such as heat capacity, thermal conductivity, and thermal expansion.

Q2. What is heat capacity, and how does it relate to the thermal properties of matter?
Ans. Heat capacity is the amount of heat energy required to raise the temperature of a substance by one degree Celsius, or Kelvin. It reflects the substance's ability to store thermal energy.

Q3. What is thermal conductivity, and why is it important in understanding the thermal properties of matter?
Ans. Thermal conductivity is a measure of how well a material conducts heat. It indicates how easily heat energy can flow through a substance, influencing its ability to conduct or insulate heat.

Q4. How does thermal expansion occur, and what role does it play in the thermal properties of matter?
Ans. Thermal expansion is the increase in volume or size of a substance as its temperature increases. It occurs because particles within the substance gain kinetic energy, causing them to move apart. Thermal expansion is crucial in various applications, such as in construction and engineering.

Q5. What factors affect the thermal properties of matter?
Ans. The thermal properties of matter depend on several factors, including the type of material, its molecular structure, density, and temperature.