**Unit 2.1 Matter**

Students continue to practice describing, identifying, and comparing solids and liquids, which should be taught at the reinforcement level to the drill-and-practice level of instruction. Students need multiple opportunities to investigate various objects in order to determine the properties of solids, liquids, and gases. Using this knowledge, children will be able to distinguish one state of matter from another, and will be able to make logical predictions about changes in the state of matter.

Since the concept of gases was introduced in third grade, it is taught in fourth grade at the reinforcement level of instruction. Students will apply their understanding of physical changes by observing and describing physical changes such as freezing, thawing, and tearing a piece of paper. Students prove that matter has weight and that the whole equals the sum of its parts, which is also taught at a reinforcement level of instruction.

(From work completed by Cranston Public Schools in collaboration with the Charles A. Dana Center at the University of Texas at Austin)

Since the concept of gases was introduced in third grade, it is taught in fourth grade at the reinforcement level of instruction. Students will apply their understanding of physical changes by observing and describing physical changes such as freezing, thawing, and tearing a piece of paper. Students prove that matter has weight and that the whole equals the sum of its parts, which is also taught at a reinforcement level of instruction.

(From work completed by Cranston Public Schools in collaboration with the Charles A. Dana Center at the University of Texas at Austin)