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Dilation is the act of expanding something

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Difference between: at rest and in motion

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Difference between: at rest and in motion

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At rest: when the position of body with respect to its surroundings doesn't change it's said to be AT REST

In motion: if the position of an object is changing, it's IN MOTION

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An object will continue to remain at rest unless acted upon by an external unbalanced force.
This is the first law of dynamics;it was understood by Galilei that described it in 1632 and then it was enunciated by Newton in 1687. The law  also states that an object  will stay in a state of constant velocity, called uniform motion, in the absence of an unbalanced force.
It means if there was no frictional or any other force the body would never stop.

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Inertia is the tendency of an object to stay at rest or in motion.

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In classical mechanics speed is not absolute but always relative to a reference frame

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There is not such things as absolute motion or absolute rest. Object move relative to each other. Therefore nothing is ever at absolute rest or absolute motion, things just move relative to each other.

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Galilean transformation of coordinates relation between the coordinates of an event as observed from two inertial reference frames

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Inertial frame is the particular refence system where the Newton's 1st law is valid

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Contraction is the act of contracting something

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Galileian law for the addition of velocities is also valid

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The Newtonian dynamics appeared to have defenitively solved the question of describing motion and its causes

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Stationary is a time-invarian quantity, such as a constant position or temperature

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Elementary particle are any of subatomic particle that compose matter and energy

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Simultaneity when two events happening at the same time

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Rest frame the coordinate axes in terms of wich position or movement may be specified

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Ether is an all-pervading, infitely elastic, massless medium

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Vacuum is absence of matter

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Medium is an intervening substance through which something is transmitted or carried on

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The Newtonian dynamics appeared to have definitively solved the question of describing motion and its causes. In classical mechanic speed is not absolute but always relative to a reference frame; if a law of dynamics is valid in a reference frame K, it must be valid in all reference frame K' moving with uniform linear motion in relation to K. The Galileian law for the adiction of velocities is also valid. Maxwell developed the theory of electromagnetism around 1870, in electromagnetism the speed of light in a vacuum is costant.
This is the fundamental postulate of special relativity, called invariance of the speed of light.

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Pheraps a privileged reference frame exists. It was called by Aristotele "Ether". The M-M experiment had the aim to demonstrate the ether existence

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The Ether is an invisible massless nothing, it’s very rarefied and highly elastic substance formerly believed to permeate all spaces, including the interstice between the particles of matter. Maxwell believed electromagnetic waves, such as light, to be vibration in the ether. Its only physical property is that it allows light propagate through.

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When the measure of speed of light (c) became possible, testing the predicted effect of the ether on the speed of light became possible too.

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If a sound wave travels through air, light waves must travel through a medium as well. A famous lluminiferous aether, in fact as the sound requires air, so the light requires the ether to move from a place to another.

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In 1887 Michelson and Morley conduct an experiment and they needed an experimental precision never had before. The idea was: the Earth orbits around the Sun at a speed of 30 km/s and it moves inside the ether, so the speed of light has to be different when the Earth moves in the same direction of the light in the ether or in a transverse direction.
M-M never detected such a difference: their results were inconsistent with the existence of the ether, but they were consistent with the point of view of Einstein. It's turning point in the history of science and in modern physics.

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The Michelson-Morley experiment was an attempt to measure the motion of the Earth through the luminous ether. Though often called the Michelson-Morley experiment, yhe phrase actually refers to a series of experiments carried out by A.Michelson in 1881 and then again (with better equipement) at Case Western University in 1887 along with chemist E.Morley. Although the ultimate result was negative, the experiment key is that it opened the door for an alternative explanation for the strange wave-like behaviour of light.

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Muon's an instable subatomic particle like an electron but it has a much great mass and a very short life. The muon exist in the uppest atmosphere. When the cosmic rays, that are high energy proton, collide with the molecules in the atmosphere, the products are muons. The muons travel at relativistic speed. If a muon is stationary it has a lifetime of 2.2 microseconds, theyare created 10 km above the surface of our planet.The muons can reach the ground, even if they take 34 microsecond to reach the ground, they are detected in cloud chambers. They don't all decay before they reach us it's possible because with the Einstein's Special Theory of relativity the  lifetime of the muons depends on the frame reference of the observer. This is the real evidence of the Einstein's Special Theory of relativity.

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Theory of relativity explained in 7 mins

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Neil deGrasse Tyson explains the Michelson-Morley experiment excerpt from UNDAUNTED

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[MP4 360p] Simultaneity - Albert Einstein and the Theory of Relativity.mp4

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[MP4 480p] Physics_ The Lorentz Transformation Equations.mp4

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I liked this kind of lessons because learn something in English, even if is more difficult than learn something in our mother tongue, is very important, because nowadays english is the most important language due to the globalization. The lessons were very simple and accessible to all the students, we had the possibility to improve our English skills, but I think during this kind of lessons the student should have more time to conversate in english, maybe we didn't this due to the time. The lessons were well structured, even if the topic is hard the material and the lesson were appropriated. Beautiful work teacher 😊, sorry for my long opinion, but i felt the need to share my opinion.

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Your padlet is really well organized.
Thank a lot for your useful comments.
Just a few mistakes in the dictation.
The evaluation is A