Experimental Design - Variables Definition A factor or condition that can change during an event or investigation 3 Types These factors are known as the: independent (“different”) dependent (“measure”) controlled (“same”)

Identifying Variables List four variables that exist for each situation: Ex: What variables can affect the sprouting of a plant seed? 1. amount of water received 2. amount of sunlight 3. amount of fertilizer 4. age of the seed

Identifying Variables (List four for each) What variables can affect the attendance at a football game? What variables can affect the taste of a soft drink? What variables can affect the speed of a runner in a 100-yard dash? What variables can affect the amount of fruit produced by an apple tree? What variables can affect the amount of rain an area receives?

Identifying Variables List the independent, dependent, and controlled variables for each situation: Ex: Students of different ages were given the same puzzle to assemble. The puzzle assembly time was measured. Ind. = different ages of students Dep. = assembly time Cont. = same puzzle

Indentifying Variables List the independent, dependent, and controlled. A study was done to find if different tire treads affect the breaking distance of a car. A study was done to measure the cleaning effectiveness of different brands of dishwashers. They all had the same water source. A study was done to see how the length of the blades of helicopters affected their maximum flying speed.