Adapted a Don Steward diagram for a Year 8 lesson on the Gradient. Started with this, and asked students to put the staircases in order of steepness. Students were talking in pairs initially (Think-Pair-Share) before coming back to a whole class discussion. We discussed how they were deciding on what steepness is and what the key features were. We came to the conclusion that more information was needed. I asked students what measurements would they like to have. Student: "Can you tell us the angles?" Me: "Sorry guys, I don't have my protractor on me!" Instead I added these values and allowed students to discuss further. The variation in the numbers allowed for comparisons and a 'discovery' of how we can calculate the gradient. This was a really nice 'hook' into the lesson and helped students understand the concept of the gradient better. Following this we formalised our method for finding the gradient as rise over run. I went through one fu