Jump to content
Sign in to follow this  
  • entries
  • comments
  • views

Physics of the African gourd drum

Sign in to follow this  


This past week, a group called the Saakumu dance troop featuring Bernard Woma came to IHS. Their performance featured multiple instruments that are atypical in the United States. For example, they brought with them an African gourd drum, which looked a lot like a curved marimba. However, a marimba's resonators are hollow pipes, whereas this gourd drum's resonators were gourds, the vegetable. This instrument is played by striking wooden bars with mallets. The work done by hitting the wooden bars with the mallet adds energy to the system at one of its natural frequencies. Tones are caused by vibrating columns of air contained within the gourd. The gourd is a closed end resonator, much like the pipes of a pipe organ, or a bottle. Another thing that I noticed is that the smaller the gourd beneath the wooden bar and the smaller the wooden bar, the higher the frequency of the sound produced.  This makes sense, when considering the fundamental frequency of a closed end resonator. There is one node and one antinode for the whole length of the resonator, meaning that the length of the resonator contains 1/4 of a wavelenth. Frequency is v / lamba, and lamba in this case equals 4L. Therefore, when L decreases, the frequency increases.

Sign in to follow this  


Recommended Comments

There are no comments to display.

Add a comment...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Terms of Use

The pages of APlusPhysics.com, Physics in Action podcasts, and other online media at this site are made available as a service to physics students, instructors, and others. Their use is encouraged and is free of charge. Teachers who wish to use materials either in a classroom demonstration format or as part of an interactive activity/lesson are granted permission (and encouraged) to do so. Linking to information on this site is allowed and encouraged, but content from APlusPhysics may not be made available elsewhere on the Internet without the author's written permission.

Copyright Notice

APlusPhysics.com, Silly Beagle Productions and Physics In Action materials are copyright protected and the author restricts their use to online usage through a live internet connection. Any downloading of files to other storage devices (hard drives, web servers, school servers, CDs, etc.) with the exception of Physics In Action podcast episodes is prohibited. The use of images, text and animations in other projects (including non-profit endeavors) is also prohibited. Requests for permission to use such material on other projects may be submitted in writing to info@aplusphysics.com. Licensing of the content of APlusPhysics.com for other uses may be considered in the future.

  • Create New...