The 8th graders are learning about continental drift and seafloor spreading. Scientists didn't always agree with continental drift (fact that the continents are moving) because no mechanism or means could be found to explain it. In the 1940s, scientists used echo sounder technology (sonar) to map the ocean floor where they discovered ridges in the center of the Atlantic ocean. They wanted to map the ocean floor for submarines so they knew how far down to go in the ocean. This led to the widespread agreement of continental drift. The 8th graders built the ocean floor in a cardboard box using cardboard, paper, and other supplies. On the cover, they had to make a slit so the other group had to use a skewer to find the depth of the pretend ocean floor.
When finished with gathering data, the students made a graph using the data they gathered. The graph represented the side view of their ocean floor box just like if they removed the sides. The students were really accurate and did a good job gathering and graphing their data. This is how echo sounder (sonar) works in that they send a sound to the ocean floor it bounces up and the computers take how long it takes to get to the boat. They use this information to put how deep the ocean floor is.
