Energy is a disciplinary core idea and a cross-cutting concept in the K-12 Framework for Science Education and the Next Generation Science Standards (NGSS). As numerous authors point out, the energy model in these standards emphasizes the connections between energy and systems. Using energy ideas to interpret or make sense of phenomena means…

Ciphers based on rotor machines were the state-of-the-art in the mid-1900s, with arguably the most famous being the German Enigma. We have found that students have great interest in the Enigma and its cryptanalysis, so we created our own rotor cipher that is simulated with shifting tables and can be cryptanalyzed. Ours and the historic rotor…

Using a conventional notation for representing forces on diagrams, students were presented with questions on the interaction between two objects. The results show that complete understanding of Newton's Third Law of Motion is quite rare, and that some problems relate to misunderstanding which force acts on each body. The use of the terms…