waves

1. Waves
• Wave-any disturbance that transmits
energy through matter or empty space
• Medium – substance through which a
wave can travel (solid, liquid, gas)
• Wave particles vibrate and pass the
energy to a particle next to it
• Mechanical waves must use a medium to
travel (sound, ocean waves)

2. • Electromagnetic waves travel without a
medium or in a vacuum (light waves from
the sun)
• Transverse wave-particles vibrate up and
down (wave travels forward while moving
perpendicular to the forward motion) - all
electromagnetic wave
• Longitudinal wave – moves back and
forth parallel with the direction of the
motion

3. • Compression – crowded
• Rarefaction-spread apart
• Properties of Waves :
• Amplitude-related to height, large wave
height, more energy
• Wavelength- distance between two crests
or compressions, shorter the wave length
the greater the energy

4. Frequency – number of waves in a given amount of
time, higher the frequency the greater the energy
Wave speed-the speed at which a wave travels
through a medium

5. Wave Behaviors
• Reflection – wave bounces back after hitting a barrier
(sound, light, heat), at same angle
• Refraction – bending of light due to a change in medium
and a change in wave speed
• Diffraction-bending of waves around a barrier or
through an opening
• Interference – the combination of two or more waves
that results in a single wave (Ex: resonance – when two
object vibrate at the same frequency)
• Absorption: energy transferred to particles of matter

6. Electromagnetic waves
• Electric fields surround all electrically
charged objects which causes the
magnetic field to be created.
• Light travels in a straight line until it hits an
object where it can be reflected, absorbed
or transmitted
• The speed of light can change depending
on the type of media (matter traveling
through)

7. • Light is a form of radiant energy (radiation)
that moves in transverse waves
• EM energy from the sun is major source of
energy on earth
• EM spectrum consists of: left to right
• Radio waves, microwaves, infrared, visible
light, ultraviolet, x-ray, and gamma rays,
all move at the speed of light
• Energy is transferred as radiation

8. • Light travels at 300,000,000 m/s through a
vacuum and slightly less through air and
other materials
• 1 light year=9,500,000,000,000 km
(distance that light can travel in one year)

9. Sound
• Sound – energy transmitted through
matter (medium), no matter, no sound
– type: mechanical (must have matter)
– structure: longitudinal wave
• Composed of compression and rarefaction
waves (the slinky)
• Travel in all directions away from the
source
• Caused by the vibration of an object

10. EM spectrum is arranged from long wavelength to
short or from low frequency to high

11. Lenses and Mirrors
• Concave and convex lenses refract (bend)
light
• Concave – converge light (come together)
• Convex – diverge light (spread out)
• Convex mirrors - diverge light (small
upright image)
• Concave mirrors – converge light, upright
magnified image if close, inverted and
smaller if far away