Technology of heat and temperature


THIS is our fifth lecture in the Science in Action series and it is on the technology of heat and temperature.
As a prelude, I feel compelled to share these few sentiments prior to going to our lecture. The Stem (science, technology, engineering and mathematics) curriculum for PNG is the correct path to embrace for PNG’s empowerment.
PNG is in desperate situation because there is so much social disparity such as poverty and lack of service delivery, unemployment as well as disrespect for oneself and or neighbours, and the list goes on.
Where is the answer? Do our politicians and government have the answers? Not at all because they cannot solve them. Not even our educated people nor in the least our unsophisticated villagers have the answers. Is it then a global problem? Yes, the answer is that it is a global problem.
One thing for sure is feed the hungry so they will be filled and create the tranquil and calm environment you would want to see. Could we work from this channel? Yes for sure because for every problem there is a solution.
Now, which is the right thing to do? Feed the hungry every day or show the method for the hungry to feed themselves so they will not come to you for food every day? You decide the correct answer.
I am now appealing to the Education Department and the Government to look at innovations and breakthrough ideas and products anyone can come up with because we are already more than 40 years old and therefore should think for ourselves to solve the mess created and accumulating in our country. For instance, I have announced my innovative and breakthrough product to solve Science text books problems from elementary to primary and secondary grades in PNG. I made mention that one will buy one of this product at the elementary Grade or Primary Grade to keep and continually use it until year 12 Science as well as Technology education in PNG.
Astoundingly, this product will show every citizen who use it, all the science and technology skills to create and innovate new products from a solid scientific and technological knowledge base and a firm foundation laid to produce top scientists and engineers. This will pave way for eradication of hungry people because it will have the capacity to create jobs and chores for everyone. As I am adamant, these vital basket of knowledge is currently missing in our science education system.
Having said this, the current idea of Stem curriculum is the step in the right direction.
The technology world we are living in today has grown and expanded from strength to strength on new breakthroughs and innovative ideas. If this nation and its leaders nurture innovation and breakthrough ideas, we will see this nation taking huge leaps just like the developed nations or our immediate Asian and Pacific neighbours. Just by going back to agriculture and praying all the time thinking that God will rescue this nation seems incomplete.
Now let’s begin with our lecture for today. In science and physics in particular, heat and temperature are closely related but are two different areas with reference to technology. Heat is the amount of thermal energy in a system. It is measured in joules and is a process quantity. That means, heat is described as it is a quantity transferable from one medium or system to another. When these two mediums are at equilibrium, then the heat is steady.

Measurement of temperature

Temperature is the measurement of the velocity of the kinetic or movement energy of atoms and molecules of a substance or a medium. The more kinetic energy of the object will result in the more temperature it will measure. Temperature is measured in either Degree Celsius(°C) or Kelvin or even in a unit called Fahrenheit(°F).
Both temperature and heat can be looked at together when trying to make some measurements of how much heat an object or a system can contain and how much of the heat is transferred.
The formula to use in this case is the mass of the substance, the specific heat capacity of the substance that is conducting the heat, the density of the substance involved together with the change in temperature that is to be transferred or gained. This formula is, Q=m x c x ΔT.
Where Q is the heat, m is the mass, c is the specific heat capacity and ΔT is the change in temperature. To get the change in temperature, the final temperature has to be subtracted from the initial temperature (ΔT = Tf – Ti). If it is a positive number then, heat is gained. If it is a negative number, then it is a loss of temperature.
The way to measure a particular temperature is to apply a law called the zeroth law of thermodynamics. Thermo is simply heat and dynamics is movement. Putting them together is the movement of heat. The zeroth law of thermodynamics states that when two substances at each end in equilibrium with a third substance in the middle are said to be in thermal equilibrium with each other. This particular law and meaning is used to measure the temperature of objects and subjects like your body temperature with a thermometer.
For instance, if you want to measure the temperature of a fish pond, you will have to take your thermometer to it and dip it there and leave it for a few minutes until it is at thermal equilibrium with the water from the pond. Then you could take the reading as the correct temperature of the fish pond.
When you take a cube of ice and leave it on the outside of a fridge, it will begin to gain heat from the outside environment until it melts and is at thermal equilibrium with its surrounding. That is the ice will turn into water or evaporate depending on the temperature of the environment. If you conversely take the same ice and place it at another place with the same temperature as that ice, then it will not change but remain the same because it is already at thermal equilibrium with its new environment.
The molecules that make up the mass of the object are very important when we look at the definition of the word temperature. It is a measure of the kinetic energy of the substance. The kinetic energy comes from the movement and the velocity of the individual atoms and molecules of the substance. It is the velocity of these vibrating particles that distribute from one medium to another until they are at equilibrium with each other. That is the reason for using specific heat capacity when trying to measure heat from a particular substance. The amount of temperature that raises a mass which is one mole of a substance by 1 kilogram by 1°C is the specific heat capacity of that substance. For instance, the specific heat capacity of water is 4,200 joules per kilogram per degree Celsius (J/kg°C) or it can also be written as J/mol °C.
This implies that, it takes 4,200 J to raise the temperature of one kg of water by 1 °C. That is, the temperature measures the average kinetic energy of the atoms or molecules in the substance or the system.
The problem in PNG is we are our own inhibitors or our own worst enemies. We do not want changes and do not want to embrace or embark on changes, limiting our opportunities for progress.
PNG has to go in the direction of creating and innovating new ideas and breakthroughs to rescue this nation from peril and a ticking time bomb.
My prayer for PNG today is rewording Jesus’ preaching. “Whatsoever you do to the least of my brothers that you do unto me. When I was hungry you gave me to eat. When I was thirsty you gave me to drink. Now enter into the home of my Father.”
Next week: The technology and sciences of fluids

  • Michael Uglo is the author of the science textbook “Science in PNG, Pacific, Asia & Caribbean” and a lecturer in Avionics, Auto-Piloting and Aircraft Engineering. Please send comments to: [email protected]

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