After having an in-depth discussion as to how some ships could have ended up in a field, fifth graders decided the best way to test their ideas was to build a model lake, which we will refer to as a mini-lake. We will track the changes in the lake over time both quantitatively and qualitatively. Students agreed that measuring the lake's mass would be important as a way to gather evidence to support the idea that the water could evaporate. Students also wondered if the water would just get absorbed by the sand. So we agreed that if it didn't change in weight, that the volume of the water would change. In addition to tracking mass, students will also track the volume of the water by looking at a mark they place on the side of the container.