# chapters 16 & 17

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Chapters 16 & 17. Physics 101 Combined Chapters on Electricity and Magnetism. Introduction to Hyperphysics. Do a “Google Search” for hyperphysics http://hyperphysics.phyastr.gsu.edu/hbase/HFrame.html. Hyperphysics Introducory Page. Electricity in the Atmosphere. - PowerPoint PPT Presentation

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• Chapters 16 & 17Physics 101 Combined Chapters on Electricity and Magnetism

• Introduction to HyperphysicsDo a Google Search for hyperphysicshttp://hyperphysics.phyastr.gsu.edu/hbase/HFrame.html

• Hyperphysics Introducory Page

• Electricity in the AtmosphereNote that the earth (ground) is normally negatively charged. The person to the right in the diagram distorts the electric field and in reality the persons head is at ground potential.

• Electric Currents in the AtmosphereA small current passes from the sky to the earth. It is on the order of 10 AWhere do these charges come from?Ans: Ionizations produced by cosmic raysThe balloon experiment proved it did not come from the earths natural radioactivity.Atmospheric physics became an interesting branch of physics.How does the atmospheric electric field continue to exist

• Typical Electric Current on a Clear Day

• The daily variation of the atmospheric electric potential with time (time is shown as GMT or Zulu Time).The potential has its peak value at 7:00 PM no matter where you measure it: Atlantic Ocean, Pacific Ocean, Arctic Ocean, etc.)

• What Maintains the Negative Charge on the Earth?There must be a source of large negative currents which must be flowing from the top of the atmosphere to the surface of the earth to keep it charged negatively!Where are the batteries to do this?Can you think of any mechanisms?

• The answer is LIGHTNING!Lightning storms carry negative charges to the earth. There are about 300 thunderstorms per day all over the earth!The total amount of thunderstorm activity is highest on the whole earth at 7:00 PM Zulu Time (GMT). With voltages of hundreds of millions and currents in the thousands amperes these lightning strikes maintain the earths negative charge.Atmospheric Physics is exciting to study. We still do not know everything about the atmosphere!And now you know The rest of the story.

• A comparison of Electrical and Gravitational ForcesG = 6.6 x 10-11 m3 / kg s2k = 9 x 109 N m2/C2

• Gravity or Electricity?Gravity 1 x 10-47 N Electrical 2.3 x 10-8 NElectricity Wins Hands Down!

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