Download WAVES CARRY ENERGY!

WAVES CARRY ENERGY!
Waves are rhythmic disturbances that carry ENERGY without carrying
matter. Molecules transport the energy in a wave by colliding with the
molecules around them. Mechanical waves travel through matter by
creating vibrations in a medium – solid, liquid or gas. Examples: Sound,
water or seismic waves.
MECHANICAL WAVES
Use matter to transfer ENERGY from particle to particle
Matter = Medium
(requires it)
TRANSVERSE
COMPRESSIONAL
(Longitudinal)
WAVE PROPERTIES
CREST
WAVELENGTH
AMPLITUDE
REST
POSITION
TROUGH
FREQUENCY
CREST – highest point of a wave
TROUGH – lowest point of a wave
WAVELENGTH – distance from peak to peak
AMPLITUDE – the distance a wave rises/falls from its rest position
FREQUENCY – the number of waves passing a given point
Frequency and Wavelength
Longer wavelengths
result in smaller
frequencies.
Larger frequencies
result in shorter
wavelengths.
As the frequency of a wave increases,
its wavelength decreases.
Frequency and wavelength are related!
TRANSVERSE WAVES
• oscillating, repetitive motion in which the medium moves at right angles
to the wave direction
• particles of the medium moving perpendicular (moves at right angle)
WAVELENGTH
CREST
AMPLITUDE
TROUGH
EXAMPLES:
Slinky, secondary seismic wave, ocean waves,
light waves, guitar strings, and a stadium wave
COMPRESSIONAL WAVES
• particles of the medium moving parallel to the direction of the wave
• oscillating, repetitive motion that moves in the same direction as the medium
• matter in the medium moves forward or backward in the same direction
of the wave
• Transfers energy from molecule to molecule through solids, liquids & gases
• Needs a medium to travel – space is a vacuum without air – sound does not
travel in space
]
RAREFACTION
]
]
WAVELENGTH
COMPRESSION
EXAMPLES Sound, dominoes, primary seismic waves, bats hearing, sonar
Electromagnetic waves are not
caused by a disturbance of particles
in a medium. Instead, it is produced
by an interaction between an electric
and a magnetic field.
Field - force or push in a region
Speed of light – 300,000 kmps
Medium - matter
Electromagnetic waves travel in
a vacuum at the same speed
Gamma Rays
HIGH
Ultraviolet
Microwave
Infrared
Frequency
LOW
Long
Short
Wavelength
(192)
100,000,000
1,000,000
10,000
Radio waves
X-rays
Cosmic rays
100
1
0.01
0.000,1
0.000,001
Visible Light
0.000,000,01
0.000,000,000,1
0.000,000,000,001
0.000,000,000,000,01
0.000,000,000,000,000,1
ELECTROMAGNETIC SPECTRUM
ELECTROMAGNETIC WAVES
• Are transverse waves that do not require matter to carry energy.
• They are produced by the motion of electrically charged particles.
• They can travel through solid, liquids or gas faster than mechanical
waves.
• They can also travel through space, or through a vacuum where
no matter exist.
•
Light is a electromagnetic wave that travels through air at
about 300,000 km/s.
• Bright lights have greater amplitudes (more energy) than the
waves that make up dim light.
• Because frequency and wavelength are related, either the
wavelength or frequency of a light wave determines the
color of the light. Blue light has a larger frequency and shorter
wavelength than red light. Red light has a shorter frequency
and a longer wavelength.
• Light travels faster through gases than in solids or liquids.
Example: speed of light is one and a half times faster in air than
it is in glass.
LIGHT WAVE BEHAVIOR
• Reflected
• Absorbed
• Transmitted
Light rays that come in contact
with a object that reflects it will
bounce right back at the same
angle it came in at - like your
reflection In a mirror.
Light rays that come in contact
with a dark object will be
absorbed into it, making the
object warmer - like your dark
colored shirt or car.
Light rays that come in contact
with something that is
translucent, or clear, will
“transmit” or go through the
object - like a window or a glass.
A MIRAGE IS AN ILLUSION CAUSED BY THE
REFRACTION OF LIGHT WAVES, MAKING
OBJECTS THAT ARE FAR AWAY TO BE
NEARBY, FLOATING IN THE AIR OR
UPSIDE DOWN.
Light rays refract as they enter and leave each
rain drop. Each color refracts at different angles
because of their different wavelengths, so they
separate into the colors of the spectrum.
As sunlight passes through the
atmosphere, its wavelength is
scattered by particles of dust in the
air. Red and yellow wavelengths
pass through the air directly, while
blue light is scattered. It is this
scattered blue light (short
wavelength) that reaches our eyes
when we see blue sky.
SOUND
• Sound is a mechanical wave that travels through air at about
340 m/s or 1100 ft. per second.
• Loud sound waves are greater amplitudes than soft sound
waves.
• Loud sounds carry more energy than soft sounds.
• Sound travels faster in a solid than a liquid, and faster in a
liquid than a gas.
• In a sound wave, either the wavelength or frequency
determines the pitch.
• Pitch is the high or low of a sound.
• Sound level (loudness) is measured in units called
decibels.
• Vocal cords produce sound by vibration.
• As the frequency of a sound wave increases, its wavelength
decreases.