A primary objective for my 8th graders is to learn the basic architecture of a controlled experiment. I have found that teaching how to deconstruct an already completed experiment really gets my students to think about experimental design and, as a result, they are designing much more robust experiments of their own.
This lesson is a new twist on this practice by giving my students the opportunity to learn about some of the great research that their peers – fellow teens – are doing!
The lesson begins with a summary of the experiment followed by a series of questions that guide students in identifying the critical parts of any valid controlled experiment such as dependent and independent variables, variables held constant, and control groups.
More about Deconstruct an Experiment: 15-year-old scares away garden-eating slugs
• Use this straightforward controlled experiment by a 15-year-old girl to teach the basics about variables, control groups and experimental groups.
• Scaffolding is provided for writing an experimental question and formal hypothesis.
• Generates a discussion about the importance of trial size to get reliable results.
• Guides critical thinking about what conclusions can be reasonably drawn from the data.
You may want to scaffold this lesson by completing it as a class and have students write the definitions for key vocabulary as you go along: dependent and independent variable, constants, control group, experimental group, and trial size.