The Electric Boy
Study Guide for Episode 9
Note: Episode numbers in Study Guides and in the Netflix Streaming edition of "Cosmos" do not always agree with those of the disk set we use in class. Let the episode titles, not the numbers, be your guide to reading about or watching the episode shown in class.
Episode 9: The Electric Boy
People
• Michael Faraday: Neil deGrasse Tyson tells us that, between Newton and Einstein, there was another genius.
• Sir Humphrey Davy: Faraday’s employer at the Royal Institute.
• James Van Allen: discovered of what we now know as the van Allen radiation belts, belts of charged particles whose movements are determined by the magnetic field lines of the earth.
• James Clerk Maxwell: Produced mathematical formulations of Faraday’s physical models of electricity and magnetism, leading to the prediction that fields travel outward from their source at the speed of light, and suggesting further that light is electromagnetic in nature.
Ideas
• Energy: A very slippery term in everyday parlance, but a very precise and rich one in physics. The physical definition is "the capacity to do work." But as you know, there are lots of ways to do work on objects. They are suggested by the different types of energy recognized by physicists, including mechanical (energy of motion), electrical, magnetic, gravitational, chemical, elastic, radiant, and numerous others. The physicist's favorite way to express quantity of energy is a unit called the joule, but all familiar energy units, including BTU, calorie, electron-volt, kilowatt-hour, and others, are just multiples or fractions of the joule. This means that all forms of energy are, in theory, the same thing.
• Field: In physics, a field is a physical quantity that has a value for each point in space and time (Wikipedia). For example, a magnetic field surrounding a bar magnet has a value of magnetic force at every point surrounding the magnet, expressing the magnitude and direction of the force that the field would exert on a susceptible object (like a piece of iron) at that point. Fields provide powerful tools for describing and understanding magnetism, electric charge, and gravitation. Michael Faraday, who coined the term, was first to realize the importance of a field as a physical entity that carries energy. To him, and to physicists today, the field is a just a much an object as the physical object (such as a magnet or electrically charged piece of plastic) that produces it.
• Faraday also wondered if gravity might also best be described as a field. Einstein took that idea and ran with it. He realized that if gravity is a field in spacetime, then there should be gravitational waves. Over a century later, scientists detected gravity waves for the first time. Read how, and more, HERE.
• Polarized light: Read all about it HERE.
• Faraday's electric motor: See a simulation of the motor HERE. The interaction between the magnetic field of the bar magnet and those of the hanging wire produces a rotation of the wire around the bar magnet. Links on this page will take you to simulations of other electric motors and other electromagnetic phenomena.
• Other computer simulations of electricity and magnetism HERE.
Updates
• Where to start? New electronic devices seem to appear every day. In a sense, every one of them is an update on the story of Michael Faraday.
• Birds On Radar: One of a birdwatcher's favorite products of Faraday's thinking is radar. Click HERE for brief instructions on how to use radar to see if any birds were migrating through your area last night.
Readings
• Faraday, The Chemical History of a Candle (a course of lectures for children, at Britain's Royal Institution during the Christmas holidays of 1860-1861). The children who heard these lectures could never have imagined that so much basic science and chemistry could be illuminated with a humble candle. The range, clarity, and cleverness of Faraday's lectures will surprise you, too. Watch these two short videos (and read the captions) to see some of the processes he demonstrates. (Video 1, Video 2).
• Can you guess who wrote this poem, without resorting to Google? After reading it and coming up with and answer or a guess, read more about the poem HERE.
Science! true daughter of Old Time thou art!
Who alterest all things with thy peering eyes.
Why preyest thou thus upon the poet's heart,
Vulture, whose wings are dull realities?
How should he love thee? or how deem thee wise,
Who wouldst not leave him in his wandering
To seek for treasure in the jewelled skies,
Albeit he soared with an undaunted wing?
Hast thou not dragged Diana from her car?
And driven the Hamadryad from the wood
To seek a shelter in some happier star?
Hast thou not torn the Naiad from her flood,
The Elfin from the green grass, and from me
The summer dream beneath the tamarind tree?
• Michael Faraday: Neil deGrasse Tyson tells us that, between Newton and Einstein, there was another genius.
• Sir Humphrey Davy: Faraday’s employer at the Royal Institute.
• James Van Allen: discovered of what we now know as the van Allen radiation belts, belts of charged particles whose movements are determined by the magnetic field lines of the earth.
• James Clerk Maxwell: Produced mathematical formulations of Faraday’s physical models of electricity and magnetism, leading to the prediction that fields travel outward from their source at the speed of light, and suggesting further that light is electromagnetic in nature.
Ideas
• Energy: A very slippery term in everyday parlance, but a very precise and rich one in physics. The physical definition is "the capacity to do work." But as you know, there are lots of ways to do work on objects. They are suggested by the different types of energy recognized by physicists, including mechanical (energy of motion), electrical, magnetic, gravitational, chemical, elastic, radiant, and numerous others. The physicist's favorite way to express quantity of energy is a unit called the joule, but all familiar energy units, including BTU, calorie, electron-volt, kilowatt-hour, and others, are just multiples or fractions of the joule. This means that all forms of energy are, in theory, the same thing.
• Field: In physics, a field is a physical quantity that has a value for each point in space and time (Wikipedia). For example, a magnetic field surrounding a bar magnet has a value of magnetic force at every point surrounding the magnet, expressing the magnitude and direction of the force that the field would exert on a susceptible object (like a piece of iron) at that point. Fields provide powerful tools for describing and understanding magnetism, electric charge, and gravitation. Michael Faraday, who coined the term, was first to realize the importance of a field as a physical entity that carries energy. To him, and to physicists today, the field is a just a much an object as the physical object (such as a magnet or electrically charged piece of plastic) that produces it.
• Faraday also wondered if gravity might also best be described as a field. Einstein took that idea and ran with it. He realized that if gravity is a field in spacetime, then there should be gravitational waves. Over a century later, scientists detected gravity waves for the first time. Read how, and more, HERE.
• Polarized light: Read all about it HERE.
• Faraday's electric motor: See a simulation of the motor HERE. The interaction between the magnetic field of the bar magnet and those of the hanging wire produces a rotation of the wire around the bar magnet. Links on this page will take you to simulations of other electric motors and other electromagnetic phenomena.
• Other computer simulations of electricity and magnetism HERE.
Updates
• Where to start? New electronic devices seem to appear every day. In a sense, every one of them is an update on the story of Michael Faraday.
• Birds On Radar: One of a birdwatcher's favorite products of Faraday's thinking is radar. Click HERE for brief instructions on how to use radar to see if any birds were migrating through your area last night.
Readings
• Faraday, The Chemical History of a Candle (a course of lectures for children, at Britain's Royal Institution during the Christmas holidays of 1860-1861). The children who heard these lectures could never have imagined that so much basic science and chemistry could be illuminated with a humble candle. The range, clarity, and cleverness of Faraday's lectures will surprise you, too. Watch these two short videos (and read the captions) to see some of the processes he demonstrates. (Video 1, Video 2).
• Can you guess who wrote this poem, without resorting to Google? After reading it and coming up with and answer or a guess, read more about the poem HERE.
Science! true daughter of Old Time thou art!
Who alterest all things with thy peering eyes.
Why preyest thou thus upon the poet's heart,
Vulture, whose wings are dull realities?
How should he love thee? or how deem thee wise,
Who wouldst not leave him in his wandering
To seek for treasure in the jewelled skies,
Albeit he soared with an undaunted wing?
Hast thou not dragged Diana from her car?
And driven the Hamadryad from the wood
To seek a shelter in some happier star?
Hast thou not torn the Naiad from her flood,
The Elfin from the green grass, and from me
The summer dream beneath the tamarind tree?
