2. History of Electricity
• Greek scientists
– 2000 years ago they realized you could create a charge
by rubbing two things together.
– Discovered electric charges
• Ben Franklin
– kite experiment in 1752
– Electricity travels through conductors
• Alessandro Volta
– In 1800, produced the first electric battery & first
man-made electric current
– He should (but doesn’t) get a lot of the credit for
figuring it all out
3. History of Electricity
• Michael Faraday
– Discovered the principals of the electric motor in
1830
– Gets credit for it
• Nikola Tesla
– Radio & TV transmission, Power transmission,
generator, AC motor
• Thomas Edison
– invented the light bulb in 1879
4. Electricity
• Energy created by moving electrons (e-)
• Flow of electric current through circuits
• Electric current moves just like water does, it flows
through circuits
5. Electricity
• Stronger current = more e- /energy flowing
• Lower current = less e- /energy flowing
• Always flows from higher concentration of
charges to lower (+ to - terminal)
6. Electric Charge
• Electric charge is a fundamental property of
matter
– Unit – Coulombs (C)
– Made of charged particles
• Protons (+), Electrons (-), or Neutral (0)
– Can tell the overall charge on an object by adding
together number of + or - charges
7. • Electrically charged – Object with an excess of
positive or negative charges
– Sometimes described as having static electricity
– Build up of these charges BEFORE you get shocked
– video
8. Static Electricity
Ex) Dragging feet on carpet, Rubbing balloon on
hair
• WHY????
– Electrons (easily given away) are transferred from
one object to the other
– If one material has excess of electrons, it becomes
negative
– Other material has a deficiency of electrons and
becomes positive
– Accumulation of imbalanced charges on objects
results in static electricity
9. • Forces that cause objects to stick together
– Size of electric force depends on:
1. The types of charges interacting
Electrical Forces
10. 2. The distance between the charges
• The farther apart, the weaker the force
3. The amount of the two charges
• The greater the charge, the greater the force
11. Grounding Objects
• Things want to ‘ground’ to become neutral
• Earth is a natural ‘ground’
– Has a infinite number or (+) & (-) charges
• Lightning rods on top of buildings
12.
13. How Lightning Works
• Thunderstorm clouds have air inside them rushing up
and down
• Air causes rain drops to collide and knock electrons off
each other
• Bottom of cloud becomes negatively charged, ground
becomes positively charged (Static electricity)
• Both the cloud and ground send out a “leader”, looking
for a place to connect and equalize their charges
• When they connect, massive amounts of electricity
move between cloud and ground, neutralizing both
• video
