Flashcards in Abeka Science Chapter 11 Deck (56):
A _________ is a periodic back-and-forth motion, or oscillation, that transmits energy.
What is the substance called through which a wave transfers?
The medium (plural media)
What are the high points of a wave called?
What are the low points of a wave called?
What are the two major types of wave?
Transverse waves and longitudinal waves
What travels through the spring when a few coils at one end of the spring are squeezed together and released?
A compression pulse
What is a series of waves called?
A wave train
What follows close behind the compression pulse and consists of a portion of the spring in which the coils are spread out?
What is the length of a single wave?
What is the maximum distance that particles are displaced by a wave?
What is the number of waves that pass a given point per unit time?
What are vibrations traveling through a medium in the form of longitudinal pressure waves?
What is the SI unit of frequency?
What is the time needed for a wave to pass?
The wave's period
Can one have sound if there is no medium?
Will the speed of the wave change if the medium does not change?
No, it will be the same.
What is speed related to wavelength and frequency?
What device is used to demonstrate the behavior of waves?
A ripple tank
What are the waves that strike an object called?
What are waves called that bounce off an object?
What law states that the angle of incidence equals that angle of reflection?
The law of reflection.
What is the imaginary line perpendicular to the reflecting surface?
Where do the refracted waves bend?
Always towards the medium that slows them down.
What is the spreading out of a wave after it passes through a narrow opening called?
True or False:
Diffraction causes the wave to spread out evenly when the opening is roughly equal to one wavelength.
What is the reinforcement or cancellation that occurs when when two or more waves meet?
What are the two types of wave interference?
Constructive and destructive interference
What does a complete sound wave consist of?
A compression pulse- a high pressure area in which the air molecules are bunched together, and a rare fraction pulse- a low pressure are in which the air molecules are farther apart.
Who used an alarm in a vacuum to show that sound needs a medium in order to be heard?
What is the strength of a sound wave?
How is the intensity of a sound related to the square of the distance?
It is inversely proportional.
What is the effect of intensity on the way the human ear perceives sound?
What unit of sound was created and named in honor of Alexander Graham Bell?
What smaller unit is commonly used instead of the bel?
What is the effect of frequency on the way the human ear perceives sound called?
What is sound that can be heard called?
What are sounds with pitches below the audible range called?
Infrasonic sounds (infra- "below", sonic- "sound")
What are sounds with pitches above audible range called?
Ultrasonic sounds (ultra- "beyond")
What is the change in frequency caused by an object's motion called?
The Doppler effect
What does the Doppler effect depend on?
True or False:
The main factor affecting the speed of sound in air is the temperature of the air.
What are speeds above the speed of sound called?
What are speeds below the speed of sound called?
What numbers describe the speed of sound and are named after Ernst Mach?
What is another name for a violent compression pulse?
A shock wave
What is the loud noise called that happens when the shock wave reaches the ear?
What are the multiple reflections causing persistence of sound called?
What is a sound called that is heard distinctly after being reflected from some object?
True or False:
An echo cannot be heard if the source of the original sound is within 17 meters of the reflecting surface.
What does sonar stand for?
Sound navigation and ranging
What system was developed during World War II to locate submerged enemy submarines?
What device uses pulses of ultrasonic sound to measure the depth of the water under a ship?
The depth finder
What is the procedure for calculating distance by measuring the tune interval that elapses between the sending of a sound wave and the return of an echo called?
What type of sonar uses a narrow beam of ultrasonic waves to scan the ocean floor in a regular pattern?
What is the process of dissipating the energy of sound waves in matter known as?