The teacher shares three Scratch projects that search a sorted list for a target number: a linear search, a binary search and a jump search that checks every tenth item and then steps back. Students first vote on Mentimeter for the one they think is most efficient. They then run each project on lists of 10, 100 and 1,000 items, read the comparisons counter the teacher has built into each project, and enter their counts in a shared Google Sheet that charts the class's results. With the chart on the board the class re-votes, and the teacher asks students who changed their vote to explain what the numbers showed, drawing out why binary search needs the list to be sorted.
Tools: Scratch, Google Sheets, Mentimeter Nine ideas for your own version in Generate
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