The Physicists Safe is an interactive revision game students can play with a working knowledge of waves and the wave equation (velocity = frequency x wavelength). Before the lesson set up a lockable box containing a mystery prize visibly padlocked shut in a prominent position. Lock the padlock with the 8 digit combination (I’d suggest attaching two standard 4 number combo locks for simplicity). Your students mission is the open the safe first and win the prize inside using their knowledge of the wave speed equation. Students solve wave equation problems and use their answers to crack the code to the safe. The full activity should take around 30-60 minutes depending on ability (usually opened in around 45 minutes). To differentiate simply ask students to work in larger teams and split the answers up from easiest to hardest (e.g. some involve conversions and standard form). Included: Main worksheet with accompanying answers Check out my other exciting resources by clicking the link below https://www.tes.com/resources/search/?authorId=2851879 Featured resource: “The Periodic Wedding Conumdrum” is a chemistry themed logic puzzle in which students are given a series of clues to help them solve the periodic table plan for Dr Element’s wedding who needs to avoid his elemental guests reacting during his ceremony. https://www.tes.com/teaching-resource/the-periodic-wedding-conundrum-12027586