object has a natural resonance frequency: a preferred
speed for vibrating back and forth. A bass drum's vibrations
produce a low-frequency sound wave. A piccolo's vibrations
produce a higher frequency wave.
tiny objects like atoms have natural frequencies. Atoms
absorb or emit energy only at specific frequencies.
Scientists use these frequencies as a kind of fingerprint
for identifying atoms. Astronomers determine the elements
in stars by studying the frequencies of light they emit.
Chemists identify compounds in materials by heating
them and studying the frequencies of light emitted or