Skittles~R in Water:From First Grade to Fick's Law

摘要

There is nothing like a visually stunning class demonstration to engage a class full of engineering students.Here is a quick one to introduce diffusion.It was adapted from a 1st grade class activity and applied in Chemical Engineering Separations.While this could easily be shown via document camera,students especially enjoy doing it themselves.1.Scatter 10-12 Skittles~R on a level disposable plate,leaving at least 0.5 inch of spacing between candies.2.Gently pour a small amount of water into the plate until about half of the candy's height is submerged.3.Watch as the dye begins to diffuse away from the individual Skittles~R.