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vocabulary
knowledge
nous and principle
concept
Critical thinking
100
Fill in: A wave is a _______ that transfers energy from one place to another.The points where the wave is highest are called___, the points where the wave is lowest are called ______.
disturbance crests troughs
100
Fill in: Light wave is a _____ wave, it is include in _____ wave.
Light wave is a electromagnetic wave, it is include in transverse wave.
100
How is loudness measured？
The most common unit used to express loudness is the decibel.
100
What is a longitudinal wave?
Longitudinal wave is a wave in which the particles of the medium vibrate parallel to the direction of wave motion.
100
Is it safe to listen to music at a level of 115 decibels?
No because 115 decibels is too loud , and it will damage our hearing.
200
True or False: 1.Some wave can transfer energy without a medium. 2.A wave transfers energy in the direction it travels.
1.True 2.True
200
Describe the relationship between frequency and period
Frequency=1/period
200
True or False： 1. Loud sounds can damage the hairs on the nerve cells in the cochlea. When these hairs are damaged, it can grow back. 2. If the sound is louder than120 decibels, it can kill the people.
1.False 2.False
200
Definition of frequency.
Frequency is the number of cycles, such as waves, in a given amount of time.
200
Are the sun's rays mechanical waves or electromagnetic wavs? Explain why.
The sun's ray are electromagnetic waves because sunlight travels from the sun earth through a vacuum.
300
Choose the correct answers: Q:If a meteorite crashed onto the moon, would huamn in earth be able hear it (on earth）?
No because sound wave can't travel through vacuum.
300
True or False: A medium can transmit all of the wave's energy in every time.
False
300
Describe what is Doppler effect?
The Doppler effect is a change in the observed frequency of a wave when the sound source, the observer, or both are moving.
300
Is a electromagnetic wave a longitudinal wave?
No,electromagnetic wave is a transverse wave.
300
Wha is the relationship between deibel and bel?
One decibel is one-tenth of a bel.
400
Fill in the brackets: 1.( )is how high or low you think a sound is. 2.As the amplitude of a sound increases, the sound becomes ( ). 3. The surface of the nerve cells in the cochlea contains thousands of ( ) ( ).
1.pitch 2.louder 3.tiny hairs
400
Fill in: Longitudinal waves also called ________waves ,are made of _____ and _______.
Longitudinal waves also called compression waves, are made of compressions and rarefactions.
400
True or False： Doppler effect only occurs with sound waves.
False
400
How are frequency, wavelength and pitch related?
A low-pitched sound has sound waves with a low frequency and a longer wavelength. A high-pitched sound has sound waves with a high frequency and a shorter wavelength
400
What is the relationship between amplitude and the loudness of a sound.
The greater the amplitude, the louder the sound.
500
Definition of amplitude.
Amplitude is the maxium distance that the particles of a wave's medium vibrate from their rest position.
500
Explain why can't sound travel through a vacuum.
Sound can't travel through a vacuum is because sound wave is a longitudinal wave, and longitudinal wave must travel through a medium, such as air.
500
How do humans hear sound?
Humans detect sound with their ears. The ear acts like a funnel for sound waves. The ear directs sound vibrations from the environment into the inner ear, where the vibrations are converted to electrical signals. The electrical signals are sent to the brain, which interprets as sound.
500
Why sound can't transfer energy in a vacuum?
Sound can't transfer energy in a vacuum because there are no particles to vibrate in a vacuum.
500
What are two properties of waves that affect the energy of waves?
They are amplitude and frequency.