s o u n d   o f

s a n d   d o l l a r s

This week, dive into a lesson on sound in the sea! During a sonar study of the mouth of Humboldt Bay, researchers noticed a few bands of backscatter, or unexplained objects found by the sonar scans. In 2001, a cohort at Humboldt State University investigated this data from 1995 and 1998 and discovered that the unexplained backscatter was from thousands of sand dollars crowding the ocean floor at the mouth of the bay!

This lesson is based on the paper published by the cohort. In this lesson, students will learn how sound travels in the ocean, how animals use it to communicate, and how scientists harness it to discover more about the sea! Anytime you use these methods to ask and answer questions, you are doing science! It doesn’t take a special kind of person to be a scientist, just exploration and curiosity.

The research from this lesson was conducted by a cohort of senior students at Humboldt State University completing their theses. This senior thesis program allows students to do hands-on, publishable research during their program!

1. If you would like to learn more about how sound works, you can watch this episode of the Magic School Bus:


2. If you would like to see sonar in action helping scientists map the ocean floor, check out this NOAA video:



3. If you would like to hear what whale song sounds like in the ocean, listen to these recordings: 

https://www.youtube.com/watch?v=5tRMqbPH_pk https://www.youtube.com/watch?v=29neQ5mLT5E

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