Thermal energy is the energy possessed by an object or system due to the movement of particles within the thing or the system. Therefore, thermal energy can be described as the ability of something to do work due to the action of its particles. So, the faster the particles move within an object or system, the higher the recorded temperature.

See the following illustration (do not copy in your note)

2. Heat and Temperature:

Heat and temperature are interconnected but do not mean the same thing. If you add warmth to something, its temperature goes up. If you reduce temperature, you are taking its heat away. 

Knowing the distinction between heat and temperature can lead to a clearer understanding of the world around us.

So, Heat ≠ Temperature

Why do they differ?

Heat is the total energy of the motion of the molecules of a substance. In contrast, temperature refers to the measure of the average ENERGY of the motions of the molecules in the substance. The heat depends on factors like the speed of the particles, the size of the particles and the number of particles, etc. The temperature, on the other hand, is independent of these factors. The SI unit of temperature is Kelvin. A temperature is a number that relates to the energy possessed by the molecules of a substance, which directly relates to the kinetic energy contained by the particles of the substance.

3. Cause and direction of heat flow:

Heat always flows from high temperature to cold temperature. Simply, hot atoms/molecules vibrate more than cold ones. So a hot vibrating atom hits a cold one and makes the cold one vibrate more. Heat goes from hot to cold because you can’t increase the energy of something without adding energy. The energy comes from the hot side.

The difference in energy between two mediums (regions) creates a flow of energy. What determines the direction of that flow is a universal tendency for systems to move from a state where energy is higher to another where it is lower to reach a state of equilibrium.

A system with specific, measurable energy having lower energy neighbouring medium(s), will see its energy flow to said surrounding medium(s) since it will tend towards reaching an equilibrium state where there is no difference in energy between those mediums.

Temperature differences maintain the transfer of heat, or heat transfer, throughout the universe. Heat transfer is the movement of energy from one place or material to another due to a temperature difference. (You will learn more about heat transfer later in this chapter.)

4. Thermal Equilibrium

Temperature measures how hot or cold a body is concerning a standard object. Two basic concepts are essential to discuss temperature changes: thermal contact and thermal equilibrium. Two objects are in thermal contact if they can affect each other’s temperature. Thermal equilibrium exists when two objects in thermal contact no longer affect each other’s temperature.

For example, if a carton of milk from the refrigerator is set on the kitchen countertop, the two objects are in thermal contact. After several hours, their temperatures are the same, then in thermal equilibrium.

5. Zeroth Law

The zeroth law is a consequence of thermal equilibrium and allows us to conclude that temperature is a well-defined physical quantity.

The zeroth law of thermodynamics states:

“If a body A and a body B are both in equilibrium with each other, then a body C which is in thermal equilibrium with body B will also be in equilibrium with body A, and the temperature of body C is equal to the temperature of body A.”

Experimentally, if object A is in equilibrium with object B, and object B is in equilibrium with object C, then object A is in equilibrium with object C. That statement of transitivity is called the zeroth law of thermodynamics. (British physicist Ralph Fowler suggested the number “zeroth” in the 1930s).

6. Thermal equilibrium as a working principle of a mercury thermometer

A device used to measure the temperature of gaseous, liquid or solid matter or a chemical reaction such as a fire. All thermometers work on the principle that warm fluids occupy more space than cold fluids. Since we know how much space a fluid, such as mercury, will fill at any given temperature, we can determine that fluid’s temperature by measuring how much space it takes up. The total internal volume of the thermometer tube is precisely engineered, and the thermometer casing carries a series of markers – which indicate the temperature of the liquid to the person using the apparatus.

A thermometer measures its temperature. It is through the concepts of thermal equilibrium and the zeroth law of thermodynamics that we can say that a thermometer measures the temperature of something else and make sense of the statement that two objects are at the same temperature. Mercury is the only metal that is a liquid at room temperature and a poor conductor of heat. The expansion characteristics of mercury are relatively linear compared with many other liquids, meaning that it can provide accurate temperature readings. Mercury has a high boiling point due to its high density. This makes it suitable for taking readings at high temperatures, which makes mercury thermometers especially useful in laboratory settings.

Temperature scales: Celsius, Fahrenheit and Kelvin /Temperature scales:

• Celsius, also known as centigrade, is a scale to measure temperature. The unit of measurement is the degree Celsius (°C). It is one of the most commonly used temperature units in the world. The unit system is named after the Swedish astronomer Anders Celsius (1701-1744), who developed a similar temperature scale. On this scale, water’s freezing point is defined as 0 °C, while water’s boiling point is defined as 100 °C.

• The fahrenheit scale is based on a scale proposed in 1724 by physicist Daniel Gabriel Fahrenheit (1686-1736). The unit of this scale is the degree Fahrenheit (°F). On this scale, water’s freezing point is defined to be 32 degrees, while water’s boiling point is defined to be 212 degrees.

• Kelvin is a unit of measurement for temperature; the null point of the Kelvin scale is absolute zero, the lowest possible temperature. The Kelvin scale is used extensively in scientific work because several physical quantities, such as the volume of an ideal gas, are directly related to absolute temperature. 
• The Kelvin is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water (precisely 0.01°C, or 32.018°F). 

The relation between three temperature scales:

Numerical examples:

Define the following terms: Absolute zero, triple point.

• Absolute zero: The coldest possible temperature: zero on the Kelvin scale and approximately -273.15°C and -459.67°F. The total absence of heat; the temperature at which all molecules would cease motion.

• Triple point: In thermodynamics, a substance’s triple point is the temperature and pressure at which the three phases of that substance coexist in thermodynamic equilibrium. It is the temperature and pressure at which the sublimation, fusion, and vaporisation curves meet. For example, the triple point of water and carbon dioxide.

                                                   For water                                                                        For Carbon dioxide

• Ideal gas:

An ideal gas is a theoretical gas composed of many randomly moving point particles that are not subject to interparticle interactions. The ideal gas concept is useful because it obeys the ideal gas law, a simplified equation of state, and is amenable to analysis under statistical mechanics.

This completes your first chapter.

Their idea was based on simulation of hypothetical conditions in the lab trying to achieve exactly similar experimental scenario on the early Earth as to test the biochemical origins of life.

Urey and Miller were testing the hypothesis of Alexander Oparin’s and J.B.S Haldane’s hypothesis, as they said that “conditions on the primitive earth favored chemical reactions that synthesized organic compounds from inorganic precursors.” This is consider to be classical experiment on the origin of life.
The reason that this experiment is consider a significant since after Miller’s death in 2007, scientists examined sealed vials preserved from the original experiments. They were able to show that there were well over 20 different amino acids produced in Miller’s original experiments. That is considerably more than those Miller originally reported, and more than the 20 that naturally occur in life.
Possibly one of the most important experiments was one conducted in 1952, when the scientists Urey and Miller, who were interested in the origin of life, and they carried out an experiment, to simulate an early Earth atmosphere. And you can see this rather ingenious apparatus where they’ve got some water boiling away inside a flask, being circulated into another container that’s got an electrical discharge apparatus. And this electrical discharge is discharging across an ancient simulated Earth atmosphere.
And they circulated this water round and round. And after a period of time, they found that the gases in this container, once they had been electrically sparked, transform themselves into amino acids, that we saw, are the building blocks of life. So, in this simple experiment, using only water and the constituents of early Earth atmosphere, these scientists managed to create the building blocks of life. This was a truly remarkable experiment, a breakthrough in astrobiology that allowed scientists to go from speculation about the origin of life, to thinking about how those early building blocks might well have formed. Nowadays we think that the atmosphere of early Earth is actually slightly different from the atmosphere that was used by Urey and Miller in the early experiments. But nevertheless this remains a remarkable and landmark experiment in the early history of Astrobiology, at least in the twentieth century. And taking our understanding of the origin of life to a new, empirical level.
References
[1] Hill H.G. & Nuth J.A. (2003). “The catalytic potential of cosmic dust: implications for prebiotic chemistry in the solar nebula and other protoplanetary systems”. Astrobiology 3 (2): 291–304. doi:10.1089/153110703769016389. PMID 14577878.
[2] Balm S.P; Hare J.P. & Kroto H.W. (1991). “The analysis of comet mass spectrometric data”. Space Science Reviews 56: 185–9. doi:10.1007/BF00178408.
[3] Miller, Stanley L. (1953). “Production of amino acids under possible primitive Earth conditions” (PDF). Science 117 (3046): 528. doi:10.1126/science.117.3046.528. PMID 13056598.
[4] Miller, Stanley L.; Harold C. Urey (1959). “Organic ccompound synthesis on the primitive Earth”. Science 130 (3370): 245. doi:10.1126/science.130.3370.245. PMID 13668555. Miller states that he made “A more complete analysis of the products” in the 1953 experiment, listing additional results.
[5] A. Lazcano, J.L. Bada (2004). “The 1953 Stanley L. Miller experiment: fifty years of prebiotic organic chemistry”. Origins of Life and Evolution of Biospheres 33 (3): 235–242. doi:10.1023/A:1024807125069. PMID 14515862.
[6] Bada, Jeffrey L. (2000). “Stanley Miller’s 70th Birthday”. Origins of life and evolution of the biosphere (Netherlands: Kluwer) 30: 107–12.
[7] BBC: The spark of life. TV documentary, BBC 4, 26 August 2009.
[8] “Right-handed amino acids were left behind”. New Scientist (2554). Reed Business Information Ltd. 2006-06-02. p. 18. Retrieved 2008-07-09.
[9] Brooks D.J. et al (2002). “Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code”. Molecular Biology and Evolution 19 (10): 1645–55. PMID 12270892

“I have never looked upon ease and happiness as ends in themselves — this critical basis I call the ideal of a pigsty. The ideals that have lighted my way, and time after time have given me new courage to face life cheerfully, have been Kindness, Beauty, and Truth. Without the sense of kinship with men of like mind, without the occupation with the objective world, the eternally unattainable in the field of art and scientific endeavors, life would have seemed empty to me. The trite objects of human efforts — possessions, outward success, luxury — have always seemed to me contemptible.

“My passionate sense of social justice and social responsibility has always contrasted oddly with my pronounced lack of need for direct contact with other human beings and human communities. I am truly a ‘lone traveler’ and have never belonged to my country, my home, my friends, or even my immediate family, with my whole heart; in the face of all these ties, I have never lost a sense of distance and a need for solitude…”

“My political ideal is democracy. Let every man be respected as an individual and no man idolized. It is an irony of fate that I myself have been the recipient of excessive admiration and reverence from my fellow-beings, through no fault, and no merit, of my own. The cause of this may well be the desire, unattainable for many, to understand the few ideas to which I have with my feeble powers attained through ceaseless struggle. I am quite aware that for any organization to reach its goals, one man must do the thinking and directing and generally bear the responsibility. But the led must not be coerced, they must be able to choose their leader. In my opinion, an autocratic system of coercion soon degenerates; force attracts men of low morality… The really valuable thing in the pageant of human life seems to me not the political state, but the creative, sentient individual, the personality; it alone creates the noble and the sublime, while the herd as such remains dull in thought and dull in feeling.

“This topic brings me to that worst outcrop of herd life, the military system, which I abhor… This plague-spot of civilization ought to be abolished with all possible speed. Heroism on command, senseless violence, and all the loathsome nonsense that goes by the name of patriotism — how passionately I hate them!

“The most beautiful experience we can have is the mysterious. It is the fundamental emotion that stands at the cradle of true art and true science. Whoever does not know it and can no longer wonder, no longer marvel, is as good as dead, and his eyes are dimmed. It was the experience of mystery — even if mixed with fear — that engendered religion. A knowledge of the existence of something we cannot penetrate, our perceptions of the profoundest reason and the most radiant beauty, which only in their most primitive forms are accessible to our minds: it is this knowledge and this emotion that constitute true religiosity. In this sense, and only this sense, I am a deeply religious man… I am satisfied with the mystery of life’s eternity and with a knowledge, a sense, of the marvelous structure of existence — as well as the humble attempt to understand even a tiny portion of the Reason that manifests itself in nature.”

 You can listen audio at    https://www.youtube.com/watch?v=3Y0_aNvH0Wo

The text of Albert Einstein’s copyrighted essay, “The World As I See It,” was shortened for our Web exhibit. The essay was originally published in “Forum and Century,” vol. 84, pp. 193-194, the thirteenth in the Forum series, Living Philosophies. It is also included in Living Philosophies (pp. 3-7) New York: Simon Schuster, 1931. For a more recent source, you can also find a copy of it in A. Einstein, Ideas and Opinions, based on Mein Weltbild, edited by Carl Seelig, New York: Bonzana Books, 1954 (pp. 8-11).

I would like to welcome him in this session to talk about  recent developments in cosmology.

• Professor Krauss, you are very busy person. How do you manage your time?

Professor Krauss: I try and agree to do many different things, and then juggle them one at a time. I find that if I don’t have a lot to do, I sometimes do very little. I tend to focus intensively on one thing at a time, and work through the list. Sometimes I have to focus on 3 or 4 very different things in a single day, but I actually like the variety as well.

• Dear Professor, first of all I would like to Congratulate for your recent book publication “The Greatest Story Ever Told…So Far” , how do you introduce this book to laymen what is the greatest story in this book?

Professor Krauss: “It is the story of the remarkable effort humans have made to understand the fundamental forces that govern nature, and to strip back the illusion of reality that we experience on human scales to understand the underlying structure beneath it.”

 

• It is said that life in the Universe can occur only when certain universal dimensionless physical constants lie within a very narrow range. In what sense, if any, is the universe fine-tuned? What conclusions should we draw from the existence of fine-tuning?

Professor Krauss: “The Universe isn’t fine tuned for life. Life is fine-tuned for the universe. If the parameters of the universe were different perhaps different life forms might be possible. Moreover, even quantities like the energy of empty space, which seems to be so small compared to the value it might have, and which, if it were any larger, would not allow galaxies to have formed, could nevertheless have been much smaller and the universe would be more conducive to life. And a value of zero for this quantity would seem very natural indeed.”

• Prof. Krauss, I kindly expect your answer in my personal question arising while going through your another famous book “A Universe from Nothing” which contains an argument, why there is something rather than nothing. How can you explain it to a non-physicist, how the universe can be created out of nothing?

Professor Krauss: “Well, quantum mechanics allows for the spontaneous emission of particles like photons, the particles that make up light, whenever an electron changes its state in an atom. The photon appears from nothing. It was not in the atom before it was emitted. It simply appeared. Similarly, it turns out that elementary particles can spontaneously appear in empty space, once again due to the properties of quantum mechanics, this time in combination with relativity. If gravity is a quantum theory, then the variables that gravity describes, space and time, become quantum mechanical in nature, and whole space-times can appear spontaneously. This means that whole universes can appear that did not exist before. And it turns out our universe has the properties that one would expect from a universe that spontaneously appeared from nothing in this way.”

• Do you agree that “philosophy” is the best way to understand Physics and Nature?

Professor Krauss: “Natural-Philosophy, what we now call Science is the best, and I believe, the only reliable way to understand how the physical universe operates.”

 

• If time (or space) is infinite, everything that can happen has already happened, even down to me typing these words, and there is no change, only cycles of varying lengths. But how could time not be infinite? How can there be no state of being at all?

Professor Krauss: “Our universe had, as far as we can tell, a beginning, about 13.8 billion years ago. As far as we can tell, both space and time may have begun then. Now, as far as we can tell, our universe may expand forever. So in that sense time could be infinite..(or as we say in physics or mathematics, semi-infinite). And it is true that if our universe exists into the indefinite future then many strange aspects of infinity, including the possible repetition of everything we experience, an infinite number of times, for separate versions of us, might be possible. But we certainly don’t know if this is the case, and the conditions of the future universe could change so that life forms like us could not exist in the far future in any case.”

 

• Once you have said “String theory doesn’t really make any predictions at this point because it’s still an evolving idea”, is there any significant development in this idea?

Professor Krauss: “There has been a lot of mathematical development, and interest techniques have been developed that have been useful in other areas of physics. But fundamentally my earlier statement remains the same.”

• You say that you are an atheist. How do you define atheism? Are you an atheist because of your scientific consciousness?

Professor Krauss: “An atheist is simply someone who finds the argument for God unconvincing. Everything I have learned as a scientist over the past 35 years makes God not only seems highly unlikely, but largely redundant even if such an entity did exist. There is no evidence for miracles, and the laws of physics describe the history of the universe back to the earliest moments of the big bang without supernatural shenanigans.”

• Professor, Is “Dishonest” the only word for someone who believes in god despite being a scientist?

Professor Krauss: “No, I don’t think so. A vague ‘deist’ notion.. Assuming some purpose or order in the universe determined by some unknown intelligence, cannot be refuted by science. It is just unnecessary. But the Gods of the world’s major religions are all not in accord with our scientific understanding of nature. I wouldn’t call it dishonesty. Religion is foisted on young people, and it is hard to overcome.. We all tend to believe in mutually contradictory things at one time or another.”

 

• Professor, let we discuss about the global scenario, In January 2017, the Doomsday Clock is set at two and a half minutes to midnight, due to a rise of strident nationalism worldwide, US President Donald Trump’s comments over North Korea, Russia, nuclear weapons, and the disbelief in the scientific consensus over climate change by the Trump Administration. What is the real picture of our planet at this point? Are we heading towards world war III?

Professor Krauss: “Who knows? The world is a dangerous place, and we have to wake up to those dangers and begin to think globally. As Einstein said many years ago after the first nuclear explosion, “Everything has changed, save the way we think”. Unfortunately our thinking remains the same.”

• In the end, What is your message to Science enthusiast of coming generation?

Professor Krauss: “Keep doing what you love. Don’t get discouraged by others. Work hard, and enjoy discussing your work with others. .”

Thank you so much professor Krause for providing me your valuable time to talk about science.

For more about Prof. Krauss go through the following Links:

• https://en.wikipedia.org/wiki/Lawrence_M._Krauss
• http://krauss.faculty.asu.edu
• https://www.richarddawkins.net/2015/10/lawrence-krauss-explains-why-science-trumps-religion-in-illegal-broadcast-to-iranians/