Sound: The Sound Bottle Experiment
Explore the fundamental physics of sound production. This simulation demonstrates how the length of a vibrating air column affects the **frequency** (pitch) of the sound produced.
Key Concepts: Vibration, Frequency, and Pitch
▼Sound is produced by **vibration**. In a musical instrument like a flute or a bottle blown over, the sound is created by the vibration of the **air column** inside the container.
The number of vibrations per second is called **frequency ($f$)**, measured in Hertz ($\text{Hz}$). Our perception of frequency is **pitch**. Higher frequency means a higher-pitched (shrieking) sound.
The relationship between the speed of sound ($v$), its frequency ($f$), and its wavelength ($\lambda$) is: $$ v = f \cdot \lambda $$
Experiment 1: Air Column Length and Pitch
Simulate changing the amount of water in a bottle, which changes the vibrating air column length.
Observe: Shorter air column = Higher frequency.
Experiment 2: Frequency Calculation Challenge
Calculate the **Frequency ($f$)** given the speed of sound and the wavelength ($\lambda$).
When you blow across the mouth of the bottle, the air column inside vibrates. A **shorter air column** vibrates faster (higher frequency), and a **longer air column** vibrates slower (lower frequency). This is why instruments like flutes and pipes use different lengths to create different notes.
Sound Wave Characteristics
**Amplitude** is the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. Our perception of amplitude is **loudness**. Greater amplitude means louder sound.
Sound is a **mechanical wave**, meaning it requires a **medium** (solid, liquid, or gas) to travel. Sound cannot propagate in a vacuum because there are no molecules to vibrate and transmit the energy.
The speed of sound is highest in **solids** (molecules are closest), lower in liquids, and lowest in **gases** (molecules are farthest apart). The speed also increases with temperature.
