Click on any one of the tabs on the left to start the lesson. The first part of the lesson is What is Density? and you can start there to go from the beginning, or you can start at another section if you already know that information. Since this lesson uses science concepts (density and buoyancy) to understand a math concept (direct and inverse variation), it is important to know that this lesson approaches inverse and direct variation according to the nature of science. So, one of the very natures of science is to experiment with different parameters or variables to see how other variables react. This will come into play when we talk about variation. However, to know which parameters, one must know which ones to hold constant, and also have an idea of what might happen to those other variables. This is part of the experimentation process and you will see that also in the lesson.