Grades K-4. Students’ investigations will teach them that physical changes include changes in size, shape, and states of matter, all of which do not produce new substances. Materials are provided for four activities in which students learn to identify examples of phase changes, investigate examples of what happens to matter both as it absorbs and loses heat, and explore changing the sizes and shapes of substances. Includes reproducible student data sheets and assessment questions. Required but not included: microwave and clock. Designed for 24 students working in groups of four. WARNING: Choking Hazard. Small Parts. Not for children under 3 yrs.