This is a great link to the Algebra I learning modules on inverse and direct variation.
This is the link to the Algebra II modules for the same county.
This is the link to the simulation that was used in the "Density and Fluids" section of the online learning module. Full credit for the simulation goes to the makers of this simulation and those at University of Colorado Boulder.
This is a great resource for exactly what this website talks about: incorportating science into the learning of mathematics. This specific chapter uses a lab on density and buoyancy to talk about direct and inverse variation, as well as other means of modeling outside of fluid mechanics.
This is a great tool to use as a calculator and also to manipulate with variables. It will give you graphs about any function, or information about any topic.
Although wikipedia shouldn't be cited for your average report, it can be a great resource for understanding some of the basics of certain concepts. This is a great article on direct and inverse variation which goes into more detail towards the middle of the article.