collecting rocks

You can teach a child a little bit about scientific classification by doing something as simple as collecting rocks. Head outside with a brown paper lunch sack and have your child collect as many rocks as possible. Encourage him or her to look for all different shapes and sizes. Spread the rocks out somewhere and ask your child to sort them. Some kids will sort by size. Others will sort by shape. And others will sort by color. These are some of the physical properties of the rocks. Talk about the method chosen by your child. Ask him or her to sort again using a different property.

Discussion for older kids: Scientists classify rocks into three main categories: igneous, sedimentary, and metamorphic. Igneous rocks form when magma cools and hardens. Sedimentary rocks form from other rocks that are exposed on Earth's surface and are broken down by wind, rain, snow, and ice. These particles eventually settle and may harden to form sedimentary rocks. Metamorphic rocks basically form when existing rocks are exposed to changes in temperature and/or pressure conditions. Sometimes the rocks reorient themselves into layers or recrystallize into larger crystals. Here's a great place to read more.