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Very very good.
You wrote an excellent article; good idea that one of put some notes on the sidelines.

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Il padlet è in continuo aggiornamento...

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The length of any object in a moving frame will appear foreshortened in the direction of motion, or contracted. The amount of contraction can be calculated from the Lorentz transformation. The length is maximum in the frame in which the object is at rest.

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What Was the Michelson-Morley Experiment?

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What Was the Michelson-Morley Experiment?

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Answer: 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, the phrase actually refers to a series of experiments carried out by Albert Michelson in 1881 and then again (with better equipment) at Case Western University in 1887 along with chemist Edward 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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The ether
• What the Ether is?
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.
• Why Ether was introduced?
If a sound wave travels through air, light waves must travel through a medium as well. As the sound requires air, so the light requires the ether to move from a lace to another.
• When?
When the measure of speed of light (c) became possible, testing the predicted effect of the ether on c became possible too.
• Who?
In 1887 Michelson an 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 (i.e. perpendicular to it).
• Their results.
Their results were inconsistent with the existence of the ether, but they were consistent with the point of view of Einstein. This is the beginning of modern physics.

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Peraphs a privileged reference frame exists, it was called by Aristotele “ether” and the M-M experiment
had the aim to demonstrate the ether existence.

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

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1) The Newtonian dynamics appeared to have definitively solved the question of describing motion and
2) In classical machanics speed is not absolute but always relative to a reference frame

3) If a law of mechanics is valid in a reference frame K, it must be valid in all reference frames K’

moving with uniform linear motion in relation to k.

4) Galilean law for the addition of velocities is also valid.

5) Maxwell developed the theory of electromagnetism around 1870.

6) In electromagnetism the speed of light in a vacuum is constant

7) This is the fundamental postulate of special relativity, called invariance of the speed of light.

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Theory of relativity explained in 7 mins

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Dilatation: The act of expanding

Contraction: The act of contracting

Reference frame: A set of coordinate axes in terms of which position or movement may be specified

Inertial frame: A reference system where the Newton's1st law is valid

Galilean trasformation of coordinates: Relation between the coordinates of an event as observed from two inertial references frame

Medium: An intervening substance through which something is transmitted or carried on

Ether: An all-pervading infinitely elastic,massless medium

Vacuum: Absence of matter

Simultaneity: Happening at the same time

Elementary particle: Any of the subatomic particle that compose matter and energy

Rest frame: The coordinate system in which the particle is at rest

Stationary: A time-invariant quantity, such as a constant position of temperature

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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 Galileo 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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At rest: when the position of a body with respect to its sorroundings doesn't change with time it is said to be at rest.
In motion: if the position of an object is changing,it's "in motion"

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Demonstrates that a body at rest continues to be at rest unless it receives on external force. It is interesting to see that when metallic strip is pulled and released, only square plate moves away and plastic coin remains in its position only. for more information visit website www.juniorscientist.in