In this activity, students will use marshmallows to model the formation of silicates – the family of minerals that make up more than 90% of Earth’s crust – then analyze their chemical and physical structures. Materials Regular marshmallows (about 10 per group of three to four students) Mini marshmallows (about 20 per group) Toothpicks (about 20 per group) Student worksheet – Download PDF Teacher answer key – Download PDF (Optional) multicolor marshmallows to use as additional elements (Optional