Thermal Properties of Matter

Thermal Properties of Matter

The physical properties of matter are dependent upon the location and the surrounding conditions. These properties can be described by the thermal properties of matter. The thermal properties of matter can be explained by the concept of thermal energy and thermal conductivity. The idea of thermal properties of matter is based on the physical laws and states that the temperature of matter is dependent on the nature of the surroundings and the thermal conductivity of the matter.

What are Thermal Properties of Matter?

Thermal properties are one of the essential characteristics of a material. The thermal property of a specific object is the reason why it retains heat, or it is the property that makes this object act in a certain way when heat fluctuates. For instance, the materials that do not conduct well will retain a high amount of energy, while those which have high thermal conductance usually lose their energies fast, becoming colder than they would generally be.

In this blog, we will study the following properties of Matter:

• Specific Heat Capacity
• Thermal Expansion
• Thermal Conductivity
• Thermal Stress
• Thermal Resistance
• Newton’s Law of Cooling
• Calorimetry
• Heat Transfer

Specific Heat Capacity

Heat capacity is measured in amounts of energy needed to increase the temperature of a substance by one degree. Using Celsius or Fahrenheit scales, different heat capacities can be compared when taking into consideration variations in chemical characteristics.

Thus, the formula is given by-

S = 1mQt

where, 

Q = Heat capacity in J

m = Mass in kg

ΔT = Temperature change in °K

Thermal Expansion

When an object is heated, the shape of the object will change or alter from its usual form. This phenomenon is known as thermal expansion. The shape, size, and surface area of the object all expand when it is placed in a hot environment or subjected to heat energy for an extended period. Take water, for example; when water becomes hotter, its volume increases, and at a given temperature, it can even divide into hydrogen and oxygen gases by this process. This type of physical change happens within almost every material on earth.

Linear Expansion

When the change due to thermal expansion is unidimensional in one dimension, it is called linear expansion.

It is given by the formula-

ΔL = α LΔT

Where,

ΔL = Change in length L

ΔT = Change in temperature

α = Coefficient of linear expansion that varies slightly with temperature.

Thermal Conductivity

Not all materials can conduct between each other. Electrons are such a commonly used conductor of electricity, which enables your computer’s motherboard to connect to a power source with lines of copper to be able to give you light when you hit the switch on the wall or enable a fan to spin and throw cool air into your living room. Among these conductors, some have high thermal conductivity, which means they can transfer more heat than others. The materials which do not conduct heat are called insulators. These kinds of objects show insulting properties.

Thermal Stress

Thermal stress is a widespread phenomenon occurring in the material world. All materials are subjected to several stressors due to thermal expansion or contraction. Thermal stress is defined as the force per unit area exerted on material by the change in temperature of the material. Thermal stress is a specific form of stress that makes the object prone to damage.

For example, you might have heard about how truck tires crack. This is because driving at high speeds for long durations on the road can cause friction that produces and elevates temperatures. The temperature rise then causes thermal stress and leads to cracks forming on the tires.

Thermal stress in the rod is given by the below formula

FA= Thermal stress = Y t

Where:

Y = Young’s modulus for the material 

A = Area of cross-section 

Thermal Resistance

The thermal resistance of a body can be defined as the opposition to the flow of heat through it. It is defined as

Thermal resistance = Length of the materialThermal conductivity Area= lKA

Newton’s Law of Cooling

Different laws play an essential role in terms of thermal physics, and one such law is Newton’s Law of Cooling. This law states that the rate at which heat is lost by a body is equivalent to or directly proportional to the difference in temperature between the body and its surroundings. In other words, if a body is hotter than its surroundings, it will cool off more quickly.

dT/dt = -K(T-Ts)

Where T = Temperature of the body

(Ts ) = Temperature of the surrounding areas

k = a constant

Calorimetry

When a high-temperature body comes in contact with a lower temperature body, energy is transferred from the high-temperature body to the low-temperature body, producing heat and therefore changing their respective temperatures. This phenomenon, known as heat transfer, can be measured by Calorimetry.

The principle of calorimetry says that,   

Heat Gained = Heat Lost

To measure how transferred heat energy affects the body, it is essential to determine whether the body stores or loses heat energy. The easiest and most common way to do this is by measuring changes in body temperature before and after a procedure. The difference in recorded temperatures shows the change in heat energy. As such, methods of studying the transfer of heat energy involve Calorimetry.

Heat Transfer

Heat energy can be transferred either between two different bodies, or it can be transferred from one portion of the body to another portion. Thus, a study of the methods and techniques that are used to enable the transfer of heat is called heat transfer. For example, if we want heat energy to be transferred from one body to another, then there should be at least a slight difference in temperatures between them, i.e., one body has to have a higher temperature than the other, and this is what heat transfer is all about.

 The rate of heat transfer is

H = Q/t = KA(T1-T2)/l

Here Q is amount of heat

T is the time period

K is thermal conductivity

T1 and T2 are lower and higher temperature of body

l is the length of thermal conductor

Conclusion

This article was about the thermal properties of matter. We explored various terms related to thermal properties of Matter such as Thermal Expansion, Thermal conductivity, Heat transfer, Newton’s law of cooling, calorimetry, and much more. We hope you liked this blog. Thanks for reading! We are always excited when one of our posts can provide helpful information on topics like this.