Academic journal article Science and Children

A Coffee Conundrum

Academic journal article Science and Children

A Coffee Conundrum

Article excerpt

Last month, we asked you about the changes in pitch you experience when tapping a coffee cup. Vibrating objects produce sounds. A vibrating guitar string, a vibrating column of air (as in a flute), and a vibrating speaker all produce sounds. How fast something vibrates determines the pitch of the sound. A high frequency (faster vibrations) produces a high pitch, and a low frequency (slower vibration) produces a low pitch.

When you hit the side of an empty coffee cup, the coffee cup vibrates and produces a sound. When you hit the side of a coffee cup containing liquid, the cup plus liquid vibrate, producing a sound. How fast the cup plus liquid vibrates, and thus the pitch produced, depends on how easy it is for the cup plus liquid to vibrate. A "sluggish" cup plus liquid will vibrate relatively slowly and produce a low pitch, and a "less sluggish" cup plus liquid will vibrate relatively fast and produce a high pitch. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.