Introduction:
The pitch of a sound refers to its perceived frequency. It is a subjective perception that allows us to differentiate between high and low sounds. The frequency of a sound wave is the number of vibrations or cycles it completes in one second and is measured in Hertz (Hz). The pitch of a sound depends solely on its frequency, and this is what distinguishes a high-pitched sound from a low-pitched sound.

Explanation:
The pitch of a sound can be understood by considering the following points:

1. Frequency:
- The pitch of a sound is directly related to its frequency.
- Frequency refers to the number of vibrations or cycles a sound wave completes in one second.
- When the frequency of a sound wave is high, the pitch is perceived as high, and when the frequency is low, the pitch is perceived as low.

2. Relationship between Frequency and Pitch:
- The relationship between frequency and pitch can be understood by considering musical notes.
- In a musical scale, higher notes are produced by vibrations with higher frequencies, while lower notes are produced by vibrations with lower frequencies.
- For example, the note 'A' above middle C on a piano has a frequency of 440 Hz, while the note 'C' one octave below has a frequency of 261.63 Hz.
- The higher the frequency, the higher the pitch perceived by our ears.

3. Perception of Pitch:
- Our ears are sensitive to a wide range of frequencies, and we perceive different pitches based on the frequency of the sound waves.
- The human audible range typically extends from about 20 Hz to 20,000 Hz.
- Sounds with frequencies below 20 Hz are referred to as infrasound, and those above 20,000 Hz are referred to as ultrasound, which are not audible to humans.

Conclusion:
In conclusion, the pitch of a sound depends solely on its frequency. A high-pitched sound is characterized by a high frequency, while a low-pitched sound is characterized by a low frequency. The relationship between frequency and pitch can be observed in musical notes, where higher notes have higher frequencies and lower notes have lower frequencies. Our ears perceive these frequency differences as differences in pitch, allowing us to differentiate between high and low sounds.