Turn your science classroom into a real investigation lab with The Mystery Box Challenge! Students use only observation, movement, sound, and magnetism to figure out what’s hidden inside a sealed box, without ever peeking inside. It’s hands-on science mystery-solving that gets every student talking, testing, and thinking like a real scientist. This ready-to-use resource includes a student handout, clear “no peeking” rules, a step-by-step testing procedure, observation and evidence tables, and CER (Claim, Evidence, Reasoning) writing prompts with sentence starters for extra support. You’ll also get a teacher setup guide, suggested mystery objects, differentiation ideas, a detailed scoring rubric, an answer key, and helpful teaching tips, plus fun science-themed visuals throughout. Perfect for grades 6–8, this 35–45 minute activity (or a quick 10–15 minute version) builds observation skills, evidence-based reasoning, and genuine curiosity, while connecting to NGSS science and engineering practices. Make science feel like a mystery worth solving!