Final answer:
Increasing the amount of air in each sound wave without altering the wave frequency changes the sound amplitude, which is associated with the loudness of the sound, while pitch, timbre, and speed remain unaffected.
Step-by-step explanation:
If we increase the amount of air that is compacted in each sound wave but keep the same number of waves, then we have changed the sound amplitude. Amplitude is related to the intensity or loudness of the sound. When we speak louder, we are increasing the amplitude of our voice's sound waves, resulting in a higher pressure of the sound that is heard. The pitch of the sound, which is determined by the frequency of the waves, remains unchanged if the number of waves per second (frequency) remains the same.
Timbre refers to the quality of a sound that is affected by the frequency, amplitude, and timing of sound waves. It is the characteristic that allows us to distinguish between different instruments playing the same note at the same loudness. Frequency affects the pitch of sound but it is not changed in this case. Meanwhile, the speed of sound is not affected by changes in amplitude under normal conditions.