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

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

Good Morning! 04/20/23Good Morning! 04/20/23

By burning the ropes, how do you measure exactly 45 minutes of time?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.

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…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

– 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

Timeline It took a long time to recover from Aristotle’s beliefs

Copernicus1473 – 1543

1500 – Dark ages end

Aristotle 384-322 B.C

Kepler1571 – 1630

Birth of Christ 0

Newton1642 - 1727

Galileo1564 – 1642

One last history lesson

One last history lesson

The Mysterious AetherThe 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…

• 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 AetherThe 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.

• 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 AetherThe 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 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 propertiesIt’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).

• 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 AetherThe 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.

• 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 AetherThe 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 AetherThe 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?

• 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 AetherThe Mysterious Aether

• The theory was finally laid to rest in 1920

• Einstein’s speech

Now for the MethodNow for the Method