# Concepts of Heat and Temperature

#### Academic Questions in PhysicsPlease check out our Test Your Knowledge page to see all Questions and Answers The rate of change of momentum is proportional to the applied force and will take place in the direction of that force. The above statement is attributed to _____. A. Albert Einstein B. Isaac Newton C. Galileo Galilei D. Neils Bohr E. Ernest Rutherford F. Marie Curie The Law of Inertia is also referred to as _____. A. 1st Law of Thermodynamics B. 2nd Law of Thermodynamics C. 3rd Law of Thermodynamics D. Newton's 1st Law of Motion E. Newton's 2nd Law of Motion F. Newton's 3rd Law of Motion The process whereby the velocity of an object increases and decreases over a period of time is best associated with the term _____. A. Speed B. Velocity C. Momentum D. Constant Velocity E. Acceleration F. Average Velocity The rate of motion is best referred to as _____. A. Speed B. Velocity C. Momentum D. Inertia E. Acceleration F. Constant Velocity Consider this expression below: A body X exerts a force FX on another body Y. In return, body Y exert a force FY back on body X. The forces FX and FY are equal in magnitude but opposite in direction. Putting the above expression into equation: FX = -FY Where FX is the action force FY is the reaction Force The above expression relates to _____. A. Theory of Force B. Force Postulate C. Einstein's proposal on Relativity D. Newton's 1st law of motion E. Newton's 2nd law of motion F. Newton's 3rd law of motion The tendency of a body to remain in a state of rest or in uniform motion is referred to as _____. A. Tension B. Uniform acceleration C. Constant acceleration D. Deceleration E. Inertia F. Velocity A change in the position of an object with reference to time is best described as _____. A. Momentum B. Displacement C. Velocity D. Acceleration E. Direction F. Motion The saying 'what goes up on earth must come down' can be best attributed to _____. A. Force B. Motion C. Mass D. Acceleration E. Average velocity F. Constant velocity ### Heat and Temperature:

Let's begin by considering the instance below:

When we pour in water of 100OC into an aluminium cup whose temperature is the same as that of its surrounding; let’s say 22OC; We will observe the followings:

1. The temperature of water inside the aluminum cup will begin to decrease from its initial 100OC.
2. The temperature of the aluminium cup will increase from its previous 22OC.
3. After some period of time, the temperature of the aluminium cup, water and the surrounding will become the same.

Note: OC = degree centigrade; and it's a unit of temperature.

For now, think of temperature as the degree of hotness or coldness of a substance or an object with reference to some standard value.

From the above instance, it can be deduced that the heat present in the water molecules are first transferred to the aluminium cup and then to the surrounding.

###### Heat from water >>> Aluminium Cup >>> Surrounding

Note: Aluminium is a metal and metals are good conductors of heat.

Eventually, the system and the surroundings will reach the same temperature; and the heat transfer ceases. It is at this point, that the water, aluminium cup and the surroundings are said to have reached thermal equilibrium.

This above paragraph is the concept of the Zeroth law of thermodynamics.

Note: Although the surrounding receives heat from the water and aluminium cup, its temperature will remain approximately unchanged for the following reasons:

1. The volume of air in the surrounding is so large.
2. The water and aluminium will not continue to permanently give out heat energy to the surrounding.
3. Diffusion will continue to occur in the surrounding.

Heat is never lost because it is a form of energy; rather it will be transferred according to the First Law of Thermodynamics which states that:

Energy can neither be created nor destroyed but can be transferred from one form to another.

Note: From our above instance, the transfer of energy (heat energy in this case) from the water to the aluminium cup and finally to the surrounding is referred to as Heat.

Heat can simply be explained as an energy that results from the transfer of energy from an object or substance or system with a higher temperature to another with a lower temperature.

Let consider another reverse instance with regards to heat:

Now, imagine that a cold bottle of water is brought out of the fridge into the kitchen. Assuming the temperature of water is 3OC while that of the kitchen environment is 22OC; the followings will occur:

1. The temperature of the cold bottle of water will start to increase from its initial 3OC.
2. The temperature of the bottle will begin to increase from its initial 3OC.
3. After some period of time, the temperature of the bottle, water and the kitchen surrounding will become the same.

Note: At no point did the coldness of the bottle or water escaped into the surrounding. Instead it is the temperature of the room that actually caused an increased temperature of the bottle and water (inside the bottle).

In fact, if the temperature of the room was higher than 22OC, heat transfer will be achieved at a much rapid rate. (That is; the rate at which the temperature of the water and bottle increases will be faster).

Since heat energy is being transferred from the kitchen surroundings to the bottle and then into the water; We can therefore conclude that heat will always be transferred from a higher region to a lower region until equilibrium is attained.

Heat is never static. It is always transferred and thus; an object will increase its temperature by gaining heat energy from its surroundings while another object simultaneously (at the same time) decreases its temperature by losing its heat energy to the surroundings. For this reason, we may also define temperature as:

The measure or ability of an object or substance to transfer heat energy to another object or substance.

The higher the temperature, the greater the ability of an object or substance to transfer heat. Conversely, the lower the temperature, the greater the tendency of an object to receive the transferred heat.

The point is:

For heat to be transferred, we must have systems or objects or substances with varying temperatures. Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.

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