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Good Morning! 11/5/2014 Your starter for today: The question that you need to write down is on the next slide. There are two lengths of rope. Each one will burn for exactly one hour when lit from one end. They are not necessarily of the same length or width as each other.They also are not of uniform width (may be wider in middle than on the end). In other words burning half of the rope doesn’t guarantee 1/2 hour has passed.The schedule is coming in a few slides
By burning the ropes, how do you measure exactly 45 minutes of time?
Light one rope at both ends and the other at only one end. When the first rope is consumed 30 minutes has passed. Light the second rope at the end that hasn’t been lit. When the second rope is consumed 15 more minutes have passed.
Today we will… • I was able to read through your answers to “What have you always wanted to know?” • Finish up with Aristotle and the beginnings of Science. • Link • Discuss the Aether (yes this is the 5th element of Aristotle’s elements) • If there is time will begin our discussion of the scientific method. • 3rd hour ends at 12:17
Timeline It took a long time to recover from Aristotle’s beliefs 1500 – Dark ages end Birth of Christ 0 Aristotle 384-322 B.C Kepler 1571 – 1630 Galileo 1564 – 1642 Newton 1642 - 1727 Copernicus 1473 – 1543
The Mysterious Aether • In order to explain refraction (the bending of light), Issac Newton's postulated an "Aethereal Medium" He did this in his book Opticks published in (1704) • Newton new three things • 1 light waves are coming from the sun and getting to the earth. • 2 light is a wave • 3 waves need something to travel through • Therefore he concluded that…
The Mysterious Aether • In the 1720 James Bradley carried out a series of experiments in order to attempt to measure stellar parallax. • Bradley's results seemed to only make sense in an aether-filled universe. • These results seemed to convince everyone that this material really did exist.
The Mysterious Aether • It was discovered that light moves ridiculously fast and combined with the fact that waves move faster through more rigid materials, we “realized” that whatever was between the sun and us must be very rigid.
It’s properties • it had to be a fluid in order to fill space, but one that was millions of times more rigid than steel in order to support the high frequencies of light waves, massless, completely transparent, non-dispersive, incompressible, continuous, and without viscosity (frictionless).
The Mysterious Aether • It had to be frictionless so that Planets couldn’t travel through so it had different properties at different times. • Now they were smart men and they knew that things can not be both frictionless and very rigid. • But they believed it anyways.
The Mysterious Aether • So they went on believing in the Aether until Michelson he set out to PROVE that Aether existed. • He unfortunately made a iron tight case against the material that he was trying to prove. • The saddest part of the story is the Michelson died insisting that the Aether existed. • His experiment
The Mysterious Aether • After Michelson’s work they had to try and figure out how light works and it was only then that they realized two things. • 1. Light waves do not require a material to move. • 2. Light exists as both a wave and a particle. • What year do you think that Aether was finally laid to rest?
The Mysterious Aether • The theory was finally laid to rest in 1920 • Einstein’s speech
