Ceramic material is used for both functional and decorative items. Dishes—plates, bowls and mugs—are often ceramic. Children make things out of clay for school projects. Tiles and hot plates are often ceramic. Because clay is flexible, it can be molded into many shapes. Depending on the trace elements, it can be different colors, have different properties (tolerance to temperature, fragility, etc.). Glazes and other surface treatments, as well as the firing temperature and length of time in a kiln can also affect the properties of the finished product.