How Engineers Test Solutions with Variables and Criteria

Crash Course Kids

This educational video from Crash Course Kids explores the critical engineering concepts of testing solutions through variables and criteria. Using relatable analogies like a slingshot mobile game and bowling, the host explains how engineers verify if their solutions actually work. The narrative demystifies the abstract concept of a "fair test" by demonstrating why changing multiple factors at once makes it impossible to know what caused a specific result. The video breaks down two main scientific method components: "criteria" (the rules for success) and "isolating variables" (changing only one thing at a time). It walks viewers through an investigation where human error acts as an uncontrolled variable, leading to the engineering solution of using a ramp to ensure consistency. Visual aids include animated diagrams, definitions of key terms, and character-driven scenarios that make these technical concepts accessible. Teachers can use this video to introduce or reinforce the scientific method and engineering design process. It is particularly useful for explaining the difference between independent and controlled variables—often a stumbling block for students. The clear examples provide a perfect launchpad for classroom experiments where students must design their own fair tests, emphasizing the importance of consistency and measurable success criteria.