Prove It!

What do you know and how do you know it? These two questions were put to the test in Mrs. Jeana Vierra’s seventh grade science class at Lakeside Middle School. What did the ancient sailors observe that caused them to change from believing that the earth was flat to knowing that the earth was round? “Merchants on shore saw the ship rise out of the sea, first the top of the sail, then the whole ship. On the way out it appeared to sink. Why?” asked Mrs. Vierra. “If the Earth were flat, then a sailor could watch a ship go out to sea and could continue to see it. It would never disappear. But first parts disappear, then all the ship,” answered one student. “If the earth was flat, you could see more things,” stated another student. This discussion came as part of an introductory learning activity in a FOSS Investigation on Planetary Science.

In their science journals, the seventh graders made predictions. “The boat would get smaller and smaller the further away it got. The Earth is obviously round because the boat would eventually come back after is supposedly fell off the Earth.” To prove their hypothesis, the seventh graders made “boats” from a straw and a piece of tape. Two replicas of the earth were given to the students: a globe and a flat earth map.

Each student selected a port of embarkation and a destination port. They then sailed their “boat” from one port (Seattle) to the other (Australia) on the flat earth map and recorded how their boat looked at the beginning, middle, and end on a provided “Shape of Earth” sheet. This was repeated using the globe. For the flat earth map, the drawings remained the same, while with the globe, the drawing of the boats became smaller, then non existent. Post investigation journal entries read: “The Earth curves and the boat seems to disappear the further away it goes. If a boat fell off, it wouldn’t appear to fade. If the Earth were flat, you could see the boat at all times until it got too small to see.”

“It was fun,” commented one seventh grader. "We got to actually see what it would look like if the world was flat, compared to round.” Her classmate added “She had us do it to find out for ourselves. So we can learn how to do research and not just go by what everyone else thinks; to create our own opinions.” “The FOSS investigations are fun and very engaging,” commented Mrs. Vierra. “I enjoy teaching with them and more importantly the kids enjoy the investigations and learn from them.” With this simple investigation, the students proved what they know; the Earth is round.