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Frequency is a fundamental concept in understanding sound waves. It represents the number of complete oscillations a wave makes in a second. Frequency is measured in hertz (Hz), where one hertz corresponds to one cycle per second.
In the context of the exercise, a frequency of 90 Hz means the sand dunes' oscillation cycle repeats 90 times every second. This is a relatively low frequency, often perceived as a booming or rumbling sound.
When thinking about frequency:

• High frequency means the sound wave oscillates more times per second, producing a higher-pitched sound.
• Low frequency results in fewer oscillations per second, leading to a deeper sound, like the rumbling from the sand dunes.

Understanding frequency helps us unravel other characteristics of sound, like its period, which is the duration of one complete cycle.

Wavelength is a crucial element in the study of waves, including sound waves. It is the distance between two consecutive points in phase on a wave, such as crest-to-crest or trough-to-trough, typically measured in meters.
Based on the step-by-step solution given, the wavelength can be calculated from the formula \( \lambda = v \cdot T \), where \( v \) is the speed of sound, and \( T \) is the period of oscillation. Here, the wavelength of the sand dune's sound was found to be approximately 3.77 meters.
Consider these points about wavelength:

• A longer wavelength corresponds to a lower frequency sound, which is deeper and travels farther.
• A shorter wavelength corresponds to a higher frequency, often resulting in a high-pitched sound that does not travel as far.

Understanding wavelength is key to comprehending the sound's behavior as it travels through various media, such as air or even the sand itself.

The speed of sound is a measure of how quickly sound waves travel through a medium, such as air, water, or solids. It varies based on environmental conditions and the nature of the medium.
In the exercise, the speed of sound was assumed to be 340 m/s, a typical speed in dry air at 20°C. This was used to calculate the wavelength of the sound produced by the sand dunes.
Key factors about the speed of sound:

• It increases with temperature since warmer air makes molecules move faster, thus transmitting sound more quickly.
• Sound travels faster in solids and liquids than in gases because particles are closer together, facilitating quicker energy transfer.

The speed of sound is essential for calculations like determining wavelengths and understanding how sound travels over distances, such as the 10 km reach mentioned for the booming sound of sand dunes.