These slides explain positive & negative controls, providing examples, explanations, and questions to prompt student thinking. Questions & answers are embedded throughout so that students can formatively assess their understanding. It is designed to support both middle & high school science students.
Students can proceed through this lesson at their own pace or work in pairs. This frees up the teacher to work 1-on-1 with students or circulate as students need support. It would work well as an introduction to these 2 concepts, remediation for students who need extra time with the topics after a lesson, or review.
If technology is not readily available at your school, you can also use this as a printed resource.