Physics and Mechanical Universe 3

Physics and Mechanical Universe 3

The mechanical universe

Performed by the California Institute of Technology The Corporation for Community College. It takes a tour of the different fields of physics: electricity, magnetism, mechanics, etc.

Lesson 41, The Michelson-Morley Experiment

In 1887, in Cleveland, Ohio, the exquisitely designed measurement of the Earth’s movement through the ether resulted in the brightest fiasco in the history of Science. Pedagogical objectives: apply the “Galileo Principle” for the composition of movements to position vectors and velocities; describe the Michelson interferometer and explain its principles; analyze why the Michelson-Morley experiment would have detected the relative movement of the ether, according to Newtonian physics.

Lesson 42, The Lorentz Transformation

If the speed of light has to be the same for all inertial observers (as indicated by the Michelson-Morley experiment) the equations of time and space can be easily found. But what do they mean? They mean that the length or speed of a clock depends on who measures it. Pedagogical objectives: use the “Lorentz transformations” to solve problems related to spaces or time intervals in different reference systems; comment on some of the hypothetical explanations set forth to justify the “Michelson-Morley experiment”; recognize the concept of length contraction; use space-time diagrams; define and comment on the concept of simultaneity; analyze the clock synchronization.

Lesson 43, Speed ​​and time.

Unlike Lorentz, Albert Einstein felt motivated to perfect the central ideas of Physics instead of seeking an explanation for the Michelson-Morley experiment. The result was a totally new way of understanding the meaning of the concepts of space and time, including aspects such as the transformation of velocities, temporal procrastination and the twin paradox. Pedagogical objectives: state Einstein’s postulates concerning the “Special Theory of Relativity”; identify the formula of the relativistic transformation of speed and how it differs from that obtained with “Galileanrelativity”; outline the ideas precise|of tangible|of actual} time and exact length and specific the equations of your time delay and length contraction; know how to use space-time diagrams in simple problems; recognize what the twin paradox consists of and comment on its solution.

Lesson 44, Energy, amount of momentum and mass.

The new meaning of space and time makes it necessary to reformulate a new mechanics. Starting from the conservation of the moment, among other things it turns out that “E = mc2”. Pedagogical objectives: define the relative momentum and the equations concerning the kinetic energy and the total energy of a particle for its velocity; comment on the relationship between mass and energy in the “Special Theory of Relativity” and analyze the hidden energy of various systems from the real masses of their constituents; Know the concept of relative mass.

Lesson 45, Temperature and the law of gases.

The oscillations of scientific research are reflected in Boyle’s experiments, as well as in Charles’ research. New and extraordinary discoveries about the behavior of gases that serve as a connection between temperature and heat, and enable an absurd temperature scale. Objectives: pedagogical: define the Celsius and Fahrenheit temperature scales and convert temperature values ​​from one scale to the other and in Kelvin degrees; interpret the “state equation” of an ideal gas, and the value of the universal gas constant in Joules / Kelvin; knowing that the average energy of a gas molecule at temperature T is of the order kT, where k is the Boltzmann constant; Identify the absolute temperature T as a measure of the kinetic energy of a gas.

Lesson 46, The machine of nature.

There was a young man named Carnot whose logic was able to demonstrate, for an expert in labor sources, that there is nothing as effective as an engine that simply does not work (David L. Goodstein, Physics student,1958) Pedagogical objectives: know the first law of Thermodynamics and use it in solving problems; calculate the work done by a gas during several almost static processes and sketch the process in a pressure-volume diagram; define the efficiency of a thermal machine; describe the “Carnot machine”; apply the expression of effectiveness to a Carnot machine.

Lesson 47, Entropy.

This program illustrates the genius of Carnot, part II, and the “Second Law of Thermodynamics.” The effectiveness of the “ideal Carnot machine” depends on the relationship between the upper and lower temperatures of the operating cycle. Beginning of the “Carnot Theory” with straightforward steam engines and ends with profound implications on the behavior of matter and additionally the flow of some time through the Universe. Education objectives: describe qualitatively the idea of entropy; calculate the amendment within the anthropy of some irreversible processes; interpret the association between the “Second Law of Thermodynamics” and also the “Entropy Principle”; perceive the role of entropy within the formation of ice.
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Lesson 48, Low temperatures.

Solid, liquid and gas are the forms of matter in the physical world. With the rummage around for low temperatures came the invention that, beneath the suitable conditions of temperature and pressure, all elements can exist in each of the three basic states of matter. Pedagogical objectives: explain what to do to cool something; list the three basic states of matter and examples thereof; explain what a phase diagram is; reproduce the phase diagram for water and explain why it is so particular; know why gases are transformed into liquid; interpret the effect of Joule-Thomson.

Lesson 49, The Atom

This program explores the history of the atom, from ancient Greece to the twentieth century, when the discoveries of JJ Thomson and Ernest Rutherford caused a new crisis in the world of Physics. Pedagogical objectives: summarize the “Kinetic Theory” and comment on the size of atoms; analyze the atomic models of Thomson and Rutherford; explain why Rutherford’s atomic model came into conflict with “Maxwell’s electromagnetic theory”; comment on the meaning of the “Brown movement” as proof of the existence of atoms.

Lesson 50, Particles and waves.

Even before the crisis of atomic models, there was already evidence that light, which is certainly a wave, could sometimes act as a particle. In the new Physics, called Quantum Mechanics, not only does light come in packages called quanta, but electrons and other particles also behave like waves. Pedagogical objectives: describe the evidence that light waves sometimes behave like particles; express the relations of “De Broglie” in a wave function with the wavelength frequency and length; interpret the Corpuscle-Wave Dualism; analyze the “Heisenberg uncertainty principle”; recognize the experimental evidence of the existence of electromagnetic waves; Define the probability function and discuss its meaning.

Lesson 51, From the atom to the quartz.

The functions of waves limited by the electric field of the nuclei, help to solve the dilemma of the atom and explain the periodic table of the elements. The very own nucleons obey a type of periodic table and follow the internal rules that lead to the idea of the quarks. Pedagogical objectives: define the wave and state function; describe the atom of Böhr in terms of wave function; interpret the periodic table in terms of electronic structure; comment on what quarks consist of and their role in the structure of matter.

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