Matter is anything that takes up space, has mass, and properties you can observe. Solids are a form of matter that has a definite shape and takes up a definite amount of space. The purpose of this activity is to learn more about solids. 1. Create a poster about solids (on a poster board, iPad, or computer). 2. If your poster was created on poster board, take a . 3. Record a summary of solids.