Proportions are mathematically hard to visualize, and can be difficult to see how the ratio of one to another impacts the proportions. Proportion Playground is a free sim from PhET that lets you quickly explore proportions. In this activity you'll play with paint balloons, beads and pool tables to see how different proportions relate to each other. Please check that PhET in HTML5 will work on your digital device BEFORE purchasing. Java applets may not work in some browsers.