Transcript Electromagnetic Waves

Electromagnetic Waves
EQ: What is an electromagnetic
wave and its properties?
Vocabulary
• Electromagnetic waves- shower of
transverse waves consisting of changing
electric and magnetic fields
• EX: Radio, infrared,visible light, UV, Xrays, gamma waves
Water & Sound Waves
• Transfer energy from one place to another.
• Need a medium to move.
Waves… a review
Water and Sound waves:
• Transfer energy.
• Need a medium to move.
ELECTROMAGNETIC WAVES
• TRANSVERSE WAVES!
• 2 properties: electrical and magnetic!
Electromagnetic (EM) waves consist
of vibrating electric and magnetic
fields.
• EM
waves travel at the
speed of light (300,000 km per second)
through a vacuum.
•
transfer energy and can
interact with matter.
ELECTRIC FIELD
• A region where charged particles are
moving.
• Found wherever there is an electric
charge.
• Surrounded by a magnetic field.
Vocabulary
EM Radiation – energy that is transferred by
electromagnetic waves
– Does not need a medium to travel
Speed of electromagnetic waves
all waves travel at the same speed in a vacuum, like
space, EMW travel at 300,000 km per second
When EMW travel through our atmosphere, they
travel more slowly but they are still the fastest waves
Takes 8 minutes for sunlight to reach earth!
Light – Waves or Particles?
• Ordinary beam has waves that vibrate in
all directions.
• Polarizing filters allow only some waves to
pass, so it is called polarized light.
Stream of Particles
Light is also made of tiny particles called
protons. When light shines on some
substances, it causes tiny particles, called
electrons, to move. When this happens an
electric current starts to flow. This is
called photoelectric effect. (PHOTONS!)
Class Work and Homework
• Fill In
– What did I learn
– Confused
– Say
– Read pages O 76 – O 79, Questions 1-4,
page 79