This two websites have great information.
http://www.hopkinsmedicine.org/hearing/hearing_testing/understanding_audiogram.html
https://www.nde-ed.org/EducationResources/HighSchool/Sound/components.htm (this one explains it really well)
This quote is from the second link:
“Intensity
Sound is a wave and waves have amplitude, or height. Amplitude is a measure of energy. The more energy a wave has, the higher its amplitude. As amplitude increases, intensity also increases. Intensity is the amount of energy a sound has over an area. The same sound is more intense if you hear it in a smaller area. In general, we call sounds with a higher intensity louder.
We are used to measuring the sounds we hear in loudness. The sound of your friend yelling is loud, while the sound of your own breathing is very soft. Loudness cannot be assigned a specific number, but intensity can. Intensity is measured in decibels.
The human ear is more sensitive to high sounds, so they may seem louder than a low noise of the same intensity. Decibels and intensity, however, do not depend on the ear. They can be measured with instruments. A whisper is about 10 decibels while thunder is 100 decibels. Listening to loud sounds, sounds with intensities above 85 decibels, may damage your ears. If a noise is loud enough, over 120 decibels, it can be painful to listen to. One hundred and twenty decibels is the threshold of pain
Sounds and their Decibels
Source of Sound Boeing 747 Civil Defense Siren Jack Hammer Rock Concert Lawn Mower Motorcycle Garbage Disposal Vacuum Cleaner Normal Conversation Light Traffic Background Noise Whisper Pitch
Pitch helps us distinguish between low and high sounds. Imagine that a singer sings the same note twice, one an octave above the other. You can hear a difference between these two sounds. That is because their pitch is different.
Pitch depends on the frequency of a sound wave. Frequency is the number of wavelengths that fit into one unit of time. Remember that a wavelength is equal to one compression and one rarefaction. Even though the singer sang the same note, because the sounds had different frequencies, we heard them as different. Frequencies are measured in hertz. One hertz is equal to one cycle of compression and rarefaction per second. High sounds have high frequencies and low sounds have low frequencies. Thunder has a frequency of only 50 hertz, while a whistle can have a frequency of 1,000 hertz.
The human ear is able to hear frequencies of 20 to 20,000 hertz. Some animals can hear sounds at even higher frequencies. The reason we cannot hear dog whistles, while they can, is because the frequency of the whistle is too high be processed by our ears. Sounds that are too high for us to hear are called ultrasonic.
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To read the entire article, go here: https://www.nde-ed.org/EducationResources/HighSchool/Sound/components.htm (this one explains it really well)