Historically, sea floor mapping (bathymetry) was done by soundings. Soundings are taken by dropping a weight with a pre-measured rope off the side of the boat and noting the measurement on the rope when the weight hits the bottom. In this activity, learners create bathymetric maps by taking soundings of simulated ocean landscapes. This activity can be used as part of a larger unit on the ocean. Also, learners can create their own landscapes to be mapped.