A cassette tape stores sound using a magnetic recording method. Here's a simplified explanation of how it works:
Inside a cassette tape, there is a long strip of plastic film coated with a magnetic material, typically iron oxide. The tape is wound between two spools, and when you play it, it passes over a magnetic playback head.
When sound is recorded onto the tape, an electrical signal from a microphone or another audio source is sent through a recording device. The device converts the electrical signal into a varying magnetic field, which is then applied to the tape as it passes over the recording head. The magnetic field magnetizes the particles on the tape's surface, aligning them in specific patterns that represent the sound waves.
The volume or loudness of a sound is determined by the strength of the electrical signal. When a sound is loud, the electrical signal will be stronger, resulting in a more intense magnetic field during the recording process. This higher intensity magnetizes the particles on the tape more strongly, creating a larger magnetic variation.
Conversely, when a sound is quiet, the electrical signal will be weaker, leading to a less intense magnetic field during recording. This weaker magnetization results in a smaller magnetic variation on the tape.
During playback, the tape passes over the magnetic playback head, which detects the changes in the magnetic field. As the magnetic particles on the tape move past the head, they induce a varying electrical current in the head's coil. This electrical signal is then amplified and sent to the speakers, reproducing the original sound.
To summarize, the cassette tape stores sound by magnetizing particles on its surface in patterns that represent the audio signal's waveform. The variation in magnetic strength corresponds to the volume or loudness of the sound, with stronger signals representing louder sounds and weaker signals representing quieter sounds.