Each capital letter is the first letter in the name of a type of energy:
magnetic
kinetic (movement energy)
heat (thermal energy)
light
gravitational potential
chemical
sound
electrical
elastic potential
nuclear.
Recall that matter is made up of particles that are arranged and behave differently in solids, liquids and gases.
Sound Energy
Sound is the energy things produce when they vibrate (move back and forth quickly). If you bang a drum, you make the tight skin vibrate at very high speed (it's so fast that you can't usually see it), forcing the air all around it to vibrate as well. As the air moves, it carries energy out from the drum in all directions. Eventually, even the air inside your ears starts vibrating—and that's when you begin to perceive the vibrating drum as a sound. In short, there are two different aspects to sound: there's a physical process that produces sound energy to start with and sends it shooting through the air, and there's a separate psychological process that happens inside our ears and brains, which convert the incoming sound energy into sensations we interpret as noises, speech, and music.
How sound travels Sound energy travels using compression waves generated by a vibrating object. As a sound wave moves forward, it makes the air bunch together in some places and spread out in others. This creates an alternating pattern of squashed-together areas (known as compressions) and stretched-out areas (known as a rarefactions). In other words, sound pushes and pulls the air back and forth.
One wavelength = the distance between successive compressions or rarefactions in a sound wave.
Frequency and Amplitude
Define frequency as the number of vibrations or per second
Define amplitude as the maximum distance that each particle in a wave moves away from its usual resting position.
The top wave represents a typical sound wave vibrating at a certain amplitude (its height) and frequency (how many peaks and troughs there are in a certain amount of time).
This wave has the same frequency as the first wave (the same number of peaks and troughs) but twice the amplitude (it's twice as high). A sound wave like this would sound louder than the first wave but the same pitch. This wave has half the frequency of the second wave (half the number of peaks and troughs) but the same amplitude (it's exactly the same height). A sound wave like this would sound deeper (lower pitched) than the second wave, about as loud as the second wave, and louder than the first wave.
This wave has twice the frequency of waves 1 and 2 and four times the frequency of wave 3, so it would sound much higher in pitch than the other waves. It has the same amplitude as waves 2 and 3, so it would sound just about as loud.
Understand that human hearing relies on vibrations being transferred from the air, through the various parts of the ear and the auditory nerve that sends signals to the brain. Identify the main parts of the human ear. Describe the relationship between the frequency of a sound and its pitch (higher frequency = high pitch). Describe the relationship between the amplitude of a sound wave and the intensity (loudness) of the sound (large amplitude = more intense sound). State that sound energy is measured in units called decibels. Explain the relationship between the number of decibels and the thresholds of pain and hearing.
With extended exposure, noises that reach a decibel level of 85 can cause permanent damage to the hair cells in the inner ear, leading to hearing loss. Many common sounds may be louder than you think… A typical conversation occurs at 60 dB – not loud enough to cause damage.