The Mystery of the Singing Sands
Imagine that you are walking in the desert. You hear the sound of musical instruments coming from the nearby sand dunes. If you’re like most people, you ask this question: Why are those sand dunes singing? If you’re a scientist, you figure out a way to answer it.
Why Do Sand Dunes Sing?
At the Dumont Dunes in Death Valley, California scientists from the California Institute of Technology in Pasadena asked themselves that question. To answer that question, they created a hypothesis (Please note that hypothesis is the correct term for a reasonable explanation that has not been thoroughly tested). This is their hypothesis: The sand dunes are like a musical instrument, perhaps a cello. The loose sand at the top is like vibrating strings. If the sand grains are about the same size, the grains hit each other at about the same frequency. This causes the sound to resonate. The hard, damp layer below is like the hard body of the cello. This layer reflects and magnifies the sound. This is a good hypothesis! But how could they test it?
With the links below, learn more about how these scientists used scientific method to test their hypothesis. Then answer the following questions.
- Nova Education: http://www.pbs.org/wgbh/nova/earth/booming-sands.html
- A more recent article (2012) on the booming sands include the following two videos. Make sure you listen to the sands!: http://science.kqed.org/quest/2012/10/25/more-clues-about-singing-sand/
- How did the scientists test their hypothesis?
- On their first attempt, the sands did not make a singing sound. What did they do next?
- What happened when they did the experiment again?
- How can the scientists be sure their hypothesis is correct?