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# WAVES CARRY ENERGY! MECHANICAL WAVES

## Presentation on theme: "WAVES CARRY ENERGY! MECHANICAL WAVES"— Presentation transcript:

WAVES CARRY ENERGY! MECHANICAL WAVES
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 WAVELENGTH CREST AMPLITUDE TROUGH FREQUENCY
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 Larger frequencies result in smaller result in shorter frequencies. wavelengths. As the frequency of a wave increases, its wavelength decreases. Frequency and wavelength are related!

TRANSVERSE WAVES EXAMPLES:
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 ] ] COMPRESSION WAVELENGTH 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

ELECTROMAGNETIC SPECTRUM
Visible Light 0.000,000,000,000,000,1 0.000,000,000,000,01 0.000,000,000,001 0.000,000,000,1 0.000,000,01 0.000,001 0.000,1 0.01 1 100 10,000 1,000,000 100,000,000 Gamma Rays Radio waves X-rays Microwave Cosmic rays Ultraviolet Infrared HIGH LOW Frequency Short Long Wavelength (192)

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 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. Reflected Absorbed Transmitted 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
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.

R O Y G B I V

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.

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