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Waves and the Electromagnetic Spectrum. WAVES. A wave is a disturbance that transfer energy from place to place. All waves move through a medium; for example sound waves move through air. Two types of waves. Longitudinal - particles move back and forth like a slinky
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WAVES • A wave is a disturbance that transfer energy from place to place. • All waves move through a medium; for example sound waves move through air.
Two types of waves • Longitudinal - particles move back and forth like a slinky • Transverse waves – waves move up and down
How can we describe a Wave • Amplitude – how far from the rest position a wave moves • Speed of Waves – Depends on the properties of the medium.
3. Wavelengths are the distance between two crests or troughs of a wave. • The crest of a wave is the highest point while the trough is the lowest point. 4. Frequency is the number of waves produced in a given amount of time. High frequency means more energy and low frequency is less
Sound Waves • Vibrating objects produce sound waves. • Sound waves travel at different speeds in different materials. Sound waves usually travel fastest in solids and slowest in gases.
Sound waves Remember that the particles of the medium move parallel to the direction that the pulse moves in longitudinalwaves. So therefore – • A sound wave traveling through air is a classic example of a longitudinal wave.
Sound and light both travel by waves. Circle the statement that best describes how their waves travel through matter. A. Sound travels through air; light travels through air. B. Sound travels through air; light travels through water and air. C. Sound travels through water and air; light travels through air. Sound travels through water and air; light travels through water and air. E. Sound travels through water, air, and metal; light travels through water and air.
The Electromagnetic Wave An electromagnetic wave is a disturbance in electric and magnetic fields.
Visible light is a small portion of this spectrum. This is the only part of this energy range that our eyes can detect. What we see is a rainbow of colors. RedOrangeYellowGreenBlueIndigoViolet ROY G BIV
Sunlight is composed of energy that is visible to humans and energy that is not visible to humans. Which statement describes how the visible energy from the Sun is different from the nonvisible energy? A. It travels at a different speed through space. B. It travels a different distance through space. C. It has different wavelengths. D. It has different amplitudes.
LIGHT • Light is a kind of energy that travels in waves. • Light waves are electromagnetic waves that can travel in matter and through a vacuum. • Light can pass through some things, but not others. • Light travels very fast and in straight lines
Transparent • An object that lets ALL light pass through are called transparent. • Examples: clear glass, eyeglasses, window, fish tank, clear plastics, and transparent tape.
TRANSLUCENT • An object that lets SOME light pass through is called translucent. • Examples: waxed paper, sunglasses, frosted glass, and thin fabrics.
OPAQUE • An object that lets NO light pass through is called opaque. • Examples: rock, metal, wood, fog, aluminum foil, thick paper, and brick.
Reflection • Reflection is when light or an image bounces back off an object’s surface. • Light can bounce back off an opaque object.
Refraction • The change in direction of a wave as it passes from one medium into another at an angle
The diagram below demonstrates how a magnifying lens can make a penny appear larger. What property of the magnifying lens is most responsible for allowing it to magnify the penny? A. It can reflect light. B. It can refract light. C. It can increase the intensity of light. D. It can increase the wavelength of light.