This document provides information about sand and windmills. It discusses how sand is formed from erosion of rocks, the different types of sand like glass sand and desert sand. It also outlines some common uses of sand in construction, leisure activities, and as a filtration medium. The document then describes different animals and plants that live in sandy environments like deserts. It provides details about desert climates and features such as oases, sand dunes, and sandstorms. Finally, it gives an overview of how a windmill works by catching wind with its blades to generate electricity.