Mapping the Ocean Floor

Introduction

Oceanographers, marine geologists, and archeologists use echo sounders to investigate objects below the surfaces of bodies of water. An echo sounder consists of a transducer that sends out and receives sound waves. A signal is sent out and bounces back from a submerged surface. Scientists use the speed of sound in water and the time it takes for the signal to bounce back to calculate the depth of the object. The deeper the object, the longer it takes for the sound to return. A map of the ocean floor is made by sending out a series of “pings” in a grid pattern and recording the depths. Echo sounders use different frequencies to map different things on the ocean floor.

Sonar, which is short for sound navigation ranging, is the name given to this echo sounding system. It was invented during World War I to detect submarines. The Vernier Motion Detector works in a similar manner. In this activity, you will use a Motion Detector to map objects on a simulated ocean floor.

Objectives

In this experiment, you will

• Use a Motion Detector to measure distances.
• Map simulated ocean floors.