Lesson Summary Students observe the properties of Mock Rocks, record through drawing, labeling and writing, compare Mock Rocks to real rocks, and use a variety of measurement tools.  Teacher Background Earth materials are solids, gases and liquids that make up the earth.  Students may have already encountered some earth materials in previous units like Pebbles, Sand and Silt or Water.  Geologists are scientists who study the rocks that make up the earth.  Geologists make careful observations of rocks for the purposes of identification, comparison, classification, and determining uses and origins of rocks.  The learners will grow in their understanding of rock and mineral properties.  They will have experiences in comparing Mock Rocks to real rocks.  The Earth Materials curriculum has students use the metric measurement system to determine diameter, circumference, depth, and mass. Set-up/Management Tips Depending on the students’ experiences with metric measurement and using centimeter graph paper, some pre-teaching of these skills might be necessary. Mock rocks should be prepared about 1 week before you plan to use them.  The directions are simple, and it does not take long.  If you utilize a parent volunteer, remind that person not to reveal ingredients to his/her student. Be careful when using weight, size, and shape to describe a rock’s properties, as these characteristics can be changed without changing the rock’s identification (i.e. breaking a rock). Literacy Support Books Available Through VAST Mediagraphies: (see Literacy Links) Science Stories “Written in Stone”  Word Wall/Word Bank The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit: geology diameter meter tape mass geologist circumference balance property depth weigh