200 likes | 277 Views
Ch 15 Waves. The Nature of Waves. Wave- Any disturbance that transmits energy through matter or empty space. Wave Energy Energy can be carried away from its source by a wave Waves transfer energy – NOT MATTER. Energy Transfer Through a Medium.
E N D
The Nature of Waves • Wave- Any disturbance that transmits energy through matter or empty space. • Wave Energy • Energy can be carried away from its source by a wave • Waves transfer energy – NOT MATTER.
Energy Transfer Through a Medium • Medium- a substance through which a wave can travel. • Can be a solid, liquid, or gas. • When a particle vibrates (moves back and forth) it can pass its energy to a particle next to it.
Types of Waves • Transverse Waves- Waves in which the particles vibrate in an up-and-down motion. • Particles move across, or perpendicular to the direction the wave is going. • Crest- The highest point of a transverse wave. • Trough- The lowest point of a transverse wave (between 2 crests)
Types of Waves • Longitudinal Waves- The particles of the medium vibrate back and forth along the path the wave moves. Particles more parallel to the direction the wave is moving • Compression- A part of a longitudinal wave where the particles are crowded together. • Rarefaction-A part where the particles are spread apart. • Sound waves are longitudinal waves.
1.2 Properties of Waves • Amplitude – Height of a wave. • The larger the amplitude is, the taller the wave is. • The larger the amplitude is, the more energy the wave has
Properties of Waves • Wavelength- The distance between any two crests or compressions next to each other in a wave. • The shorter the wavelength the more energy the wave has.
Properties of Waves • Frequency- The number of waves produced in a given amount of time. • Expressed in Hertz (Hz) • 1 Hz = 1/s • Higher frequency means higher energy
Properties of Waves • Wave Speed: • The speed at which the wave travels • V = λ x f • SI Units
Frequency and Wavelength Relationship • Frequency and wavelength are inversely related. • An increase in frequency causes a decrease in wavelength • An increase in wavelength causes a decrease in frequency
Calculations • Determine the wave speed of a wave that has a wavelength of 5 m and a frequency of 4 Hz.
Calculations • What is the frequency of a wave if the wave has a speed of 12 m/s and a wavelength of 3 m?
Calculations • A wave has a frequency of 5 Hz and a speed of 18 m/s. What is the wavelength?
Wave Interactions • Transmitted Waves • Refraction- The bending of a wave as the wave passes from one medium to another at an angle • Wave speed changes when a wave moves from one medium
Refraction of Different Colors • Dispersion- Light rays are spread out into separate colors. • Each color of light has it’s own wavelength. • Diffraction- The bending of waves around a barrier or through an opening that changes its direction
Wave Interactions • Interference- Waves occupy the same space at the same time. • Constructive Interference- the crest of one wave overlaps the crest of another wave. • The new amplitude of the combined wave is larger than the original waves • Destructive Interference- The crest of one wave overlaps with the trough of another wave. • The new amplitude of the combined wave is smaller than the original waves.