I was looking for something simple for my outreach project in western Brazil last October, so I decided to work with sand grains. In the images, we have some commercially mined sand from Aquidauana, state of Mato Grosso do Sul, Brazil. It was wonderful to see the kids (4-6 grade from nearby public schools in the city of Corumbá) marvel at the different shapes, sizes, and angularity of these beautiful quartz grains. The Pantanal and the Paraguay River that courses through it is full of quartz sand and silt.