Physics

Concepts of Heat and Temperature

len Alfred Ajibola - Tue, 14th May, 2019 @ 16:00: PM

Topics in Physics

Derived Units: Similarities and Differences with Fundamental Units Gravity: Interesting facts on Gravity Relative Density of Substances and Specific Gravity Types of Heat Transfer: Conduction Types of Heat Transfer: Convection Types of Heat Transfer: Radiation Physics Scheme of Work, SS1, First Term Physics Scheme of Work, SS1, Second Term Physics Scheme of Work, SS1, Third Term Velocity and Acceleration Newton's Laws of Motion Importance of Gravity What is Density? Density of various Substances Concepts of Force and Motion Motion and Speed Concept of Heat Transfer Concepts of Heat and Temperature Gravity: What is Gravity? Zeroth Law of Thermodynamics - Thermal Equilibrium Fundamental Quantities and Units in Physics


Academic Questions in Physics

Please 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

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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.

Please read on Fundamental and Derived Units here.

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.

Please read on the Physical Properties of Metals here.

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.

Please read more on Heat Transfer by Conduction here.

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

Please read on the Zeroth Law of Thermodynamics here.

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.
    Please read on the Composition of the Atmosphere (Air) here.
  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.
    Please read on Graham's Law of Diffusion here.

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.

Please read on the Law of Thermodynamics in Food Pyramid here.

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.

Please read on Heat Transfer by Convection here.

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.

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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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Amazing facts in Physics

Glass Ball - Len Academy

Glass Balls actually bounce higher than Rubber Balls

Every planet has its own unique gravitational force. For instance, Mars has a gravity of 3.711 m/s2 while earth’s gravitational force is 9.807m/s2.

Please read on gravity here

When two metals are put together in space, they will stick together as if they are welded. This phenomenon is called cold welding

The fastest animal on land is Cheetah. It can reach a maximum speed of about 113km per hour.

Please read on motion, speed, velocity and acceeration here


NOTABLE POINTS IN Physics

The Classical Mechanics (Laws of Motion) is a fundamental part of Physics.

Below are the Newton's Laws of Motion:

An object at rest will continue in its state of rest; while an object in uniform motion will continue in a straight line, unless an external force acts on it.

Newton's First Law of Motion.

Please read on Motion and Speed here.

The rate of change of momemtum is proportional to the applied force and will take place in the direction of that force.

Newton's Second Law of Motion.

To every action, there is an equal and opposite reaction.

Newton's Third Law of Motion.

Please read on Newton's Laws of Motion here.

The study of Thermodynamics revolves around the relationship between heat, temperature, energy and mechanical work; and these can be summarised under the 4 laws of Thermodynamics (Numbered zero through three).

You can read on the Concepts of Heat and Temperature here.

Below are the 4 laws of thermodynamics:

Zeroth law of thermodynamics – If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.

Please read on the Zeroth Law of Thermodynamics here.

1st law of thermodynamics – Energy can neither be created nor destroyed but can be changed from one form to another.

You can read on the Food Chain here.

2nd law of thermodynamics – The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

3rd law of thermodynamics – As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.

Fuses are present in many electrical devices. They are basically 🔥 fire-breakers 🔥

If there is a power surge, the fuse will break, preventing damage to the electrical devices. It will also prevent the incidence of 🔥 fire🔥 on or from such device.

Physics is one of the core sciences.

Physics is defined the scientific study of matter and the movement of matter through the space and time of the universe.

Understanding the basic and fundamental concepts of physics will help you better comprehend this subject. Below are some of the concepts:

  1. The Laws of Motion (Classical Mechanics)
  2. Electromagnetism
  3. Relativity
  4. Thermodynamics

Please read on the basic introduction of the above physics concept here