Key Terms: Echo, sonar

SonarUnderwater Sound Navigation And

Ranging.Used extensively during World War II.Uses sound waves and echos.Is used to determine the distance between two

objects underwater.

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How Does Sonar Work?A source sends out a

sound wave.The sound wave goes out

and bounces off an object causing an echo.

The echo returns to the source.

The time it takes for the echo to return to the source is recorded.

The speed of sound in water is known.(1507 meters per second)

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Formula for Calculating Distance using Sonar

D= V ( .5 xT)D = DistanceT = TimeV = Speed of sound in water

1.507 km/sec

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What did Geoscientists Discover Using Sonar ?

After World War II, geoscientists used sonar as a tool to map the entire ocean floor.

Using sonar, geoscientists made an unexpected shocking discovery about the floor of the ocean that surprised the scientific community.

We will be doing an activity using calculated sonar data to see what was discovered.

Activity.Wiki Data/Excel Spreadsheet

Use your group’s the “Mapping the Atlantic Ocean Floor Data” form to enter your data.

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