Transcript Electric Charges and Currents

Electric Charges and Currents
Electric Charge
• 3 parts of an atom
– Proton ( + )
– Neutron ( o )
– Electron ( - )
• Like charges repel
• Different charges
attract
Electric Field
• An electric field
extends outward
through space
around every
charged particle
• It is strongest near
the charged particle
Static Electricity
• Objects become
charged when they gain
or lose electrons
• Friction occurs when
two objects are rubbed
against each other
• Static electricity is the
buildup of electric
charges on an object
Conductors/Insulators
• Conductors permit
electric charges to flow
freely
- examples: metals, Earth
• Insulators do not allow
electric charges to flow
freely
• - examples: rubber, glass,
wood, plastic, air
Lightning
• Lightning forms when
there is a discharge of
static electricity
• Bolt travels from
negative charges to
positive charges
• Elect. Pot. Difference is
the amount of work
required to move a
charge (Volts)
Batteries
• A battery is a device
that produces
electricity by
converting chemical
energy into electrical
energy
• Batteries can be
either dry cell or wet
cell
Thermocouples
• A thermocouple is a
device that
produces electrical
energy from heat
energy
• Used in car engines,
ovens, and gas
furnaces
Electric Circuits
• A circuit provides a
complete, closed
pathway in which
electricity can flow
• Two types
(series/parallel)
• Our homes have
parallel circuits - if
one light goes out, the
others stay on
Two Types of Circuits
QuickTime™ and a
Sorenson Video decompressor
are needed to see this picture.
Electrical Safety
• Houses are
protected against
fires by fuses and
circuit breakers
• Know the 6 electric
safety rules on
pages 37-38