1. What Is Frequency?
Frequency is the number of vibrations made in one second. It tells how fast an object is vibrating.
The unit of frequency is hertz (Hz).
Higher frequency means more vibrations per second; lower frequency means fewer vibrations per second.
2. What Is Pitch?
Pitch is the quality of sound that tells us whether a sound is high or low.
A sound with high pitch feels sharp or shrill, while a low-pitched sound feels deep or heavy.
2.1. How We Sense Pitch
The sensation of pitch comes from the brain interpreting how fast the sound waves reach the ear. Faster vibration → higher pitch. Slower vibration → lower pitch.
3. Relation Between Pitch and Frequency
Pitch depends directly on frequency:
- Higher frequency → higher pitch
- Lower frequency → lower pitch
3.1. Mathematical View
If an object completes \( f \) vibrations in one second, then frequency is simply \( f \). Increasing the number of vibrations increases the pitch.
3.2. Everyday Observation
- A whistle produces a high-frequency sound → high pitch.
- A drum produces a low-frequency sound → low pitch.
4. Examples Showing Pitch and Frequency
- Thinner guitar strings vibrate faster → higher pitch.
- Thicker strings vibrate slower → lower pitch.
- A child’s voice is usually higher pitched than an adult’s voice.
- A flute produces high-pitched notes, while a bass drum produces low-pitched notes.
5. Graphs and Wave Patterns
Frequency can also be seen in wave patterns:
- High-pitch sounds have waves that are closely spaced.
- Low-pitch sounds have waves that are widely spaced.
5.1. Visual Understanding
Imagine two wave patterns drawn on paper: one with many cycles close together (high frequency), and another with fewer cycles spread out (low frequency). This simple picture shows the connection between pitch and vibration speed.