Thomas Graham discovered the law that bears his name while studying gas diffusion into air and other gases. He also found that the same relationship held with gas effusion, the movement of gases through a pinhole into a vacuum. Modern understanding of diffusion and effusion is based on kinetic-molecular theory, and it is generally accepted that…

The "Next Generation Science Standards" (NGSS) challenges science teachers to think beyond specific content standards when considering how to design and implement curriculum. This lesson, "Windmills by Design," is an insightful lesson in how science teachers can create and implement a cross-cutting lesson to teach the concepts…