What is a Variable?

Types of Variables Independent Variable (a.k.a. “Manipulated Variable” or “Test Variable”) The condition that will be changed by the scientist in an experiment.

Types of Variables Dependant Variable (a.k.a. “Responding Variable”) The condition(s) that will be measured in an experiment; these are the experimental data.

Types of Variables The Controls/Constants (a.k.a. “Controlled Variables) The conditions that are kept the same (unchanged) in an experiment. Typically, several can be identified.

Identify variables for the following three experiments. Practice Identify variables for the following three experiments. You can do it!

Testable Question #1 Does changing the temperature of a ball affect the height the ball will bounce? Cold Hot With the person next to you, determine the following: What is the dependent variable? What is the independent variable? What are the constants?

Identify Variables #1 Independent Variable Does changing the temperature of a ball affect the height the ball will bounce? Independent Variable Cold Hot Dependant Variable

Identify Variables #1 Constants, or Controlled Variables (which things do not/are not changed) : * Same ball * Dropped from the same height * Dropped onto the same surface * etc…

Testable Question #2 Does changing the color of light affect the growth rate of plants? With the person next to you, determine the following: What is the dependent variable? What is the independent variable? What are the constants?

Dependent Variable (Responding) Identify Variables #2 Does changing the color of light affect the growth rate of plants? Independent Variable (Manipulated) Dependent Variable (Responding)

Identify Variables #2 What are the ‘Constants’, the Controlled Variables: * Same type / size of plant * Same wattage of bulb * Same amount of water * Same soil * Light on for the same amount of time * etc…

Testable Question #3 How does the size of a parachute affect the time it takes a toy hippo to fall 10 feet? With the person next to you, determine the following: What is the dependent variable? What is the independent variable? What are the constants?

Identify Variables #3 Independent Variable How does the size of a parachute affect the time it takes a toy hippo to fall 10 feet? Independent Variable Dependent Variable

Identify Variables #3 The Constants, or Controlled Variables: * Same hippo * Dropped from the same height * Same parachute fabric * Same length of strings on the parachute * etc…