Bring the NGSS to life with this hands‑on, high‑engagement investigation that helps students prove that matter never disappears! In this 5th grade science lab, students measure and graph the weight of substances before and after melting, dissolving, and reacting — all to uncover the truth behind the Great Matter Mix‑Up. Perfect for NGSS 5‑PS1‑2, this activity builds deep understanding of conservation of matter, particle behavior, and scientific data analysis. Students work as Science Investig