The Missing Variable
Identify the missing variable in an investigation: learn to recognize when a confounding variable has not been controlled and how its absence undermines the validity of an experimental conclusion.
Key Concepts
Most of the time during a Full Moon, the alignment is imperfect. From a "top down" view, they look aligned, but from a "side" view, they are not.
This implies there is a vertical difference in the system preventing the shadow from hitting the Moon every month.
Common Questions
What is a missing variable in a scientific investigation?
A missing variable is a factor that was not measured or controlled but could explain the experimental results. If this variable is not accounted for, the experiment's conclusion may be incorrect.
How do confounding variables affect experimental results?
A confounding variable changes alongside the independent variable, making it impossible to determine which variable actually caused the observed effect. This undermines the ability to draw valid conclusions.
How do Grade 8 students identify missing variables?
Students examine experimental designs, list all factors that could affect the outcome, and check whether each is held constant or measured. Any influential factor not accounted for is a potential missing variable.