Divide students up into small groups of four or five students. Provide each group with a poster board and colored markers. Have them draw out an ocean floor map including features they have learned about such as the continental shelf and slope, mid-ocean range, a bay, abyssal plains and hills, atoll, guyot, and island, rift valley, seamount, trench, canyon and subduction zone. Have students label each of the features of the floor.
Once students have designed their group topography of the ocean floor, have each group demonstrate their understanding by constructing shoebox models. Make enough dough to divide among each group of students. You will need a bowl, spoon, flour (2 parts), salt (1 part), water (1 part), blue food coloring (2 to 3 drops) and a cardboard shoe box for each group. Mix water and food coloring in the bowl. Add flour and salt and mix until a dough forms. Divide the dough among the groups and have students create a model of their poster mapping of the ocean floor. Allow the dough to dry for a few days. Once the dough has hardened, have students label each topographical feature.
For students to understand how oceanographers use sonar and measures called fathoms to map the unseen landscape below the ocean's surface, students can simulate sonar probing using their ocean floor models and wooden cooking skewers. Supply each group with two sheets of graphing paper and label both grid papers in rows A through G. Label the columns one through 13. Have students glue one grid to the shoe box lid. Place the lid on the shoe box containing the ocean floor model. At the intersection of each row and line, punch a small hole with the tip of a wooden skewer. Provide each group with a second wooden skewer. With a black marker, segment and draw a line every 1/2 inch up the skewer from the tip of the point to the top. Have students insert the marked wooden skewer into each hole to probe and measure the depth as it hits various ocean floor features, and record the measurement data on the corresponding, second labeled graph paper. Students should notice the varying depths they are recording.
Show students what ocean floor contour maps look like with their circles of depths. Using the depth numbers on the data graph, have students plot a contour line by drawing a line, connecting all the1/2-inch depth readings, another line connecting the 1-inch depth reading and so forth. Student's can replicate real contour maps by coloring in each depth area with different shades of blue colored pencils; coloring lighter to darker as the depths increase. Compare the contour map with the model within the shoebox.