Independent/Dependent Variables

Variables in an investigation are things that can change. Variables include the environment where the experiment is performed, thus light, temperature and humidity might affect the experimental results. But, if these variable stay the same, they are called controlled variables. Controlled variables are assumed to not affect the results of the experiment.

In a cause/effect investigation, you want only two variables to change. One of the variables is called the independent variable. The independent variable will cause the other variable, called the dependent variable, to change.

 

Independent Variable     Affects (cause to change)         > Dependent Variable

 

1. Design an investigation using eye color as an independent variable.

What effect does eye color have on the dependent variable?

Research–Google “What does eye color affect?”
You need a variable that is affected by eye color. You also need a variable that you can measure how it changes.

For example: Eye color is said to affect reaction time. Brown eyes have more pigment called melanin and melanin is thought to increase nerve impulses, which carry messages to the brain.

You could use online reaction tests, such as:

2. Design an investigaton using eye color as a dependent variable.

This time eye color is the dependent variable, so you have to research things that might affect eye color. Since eye color is an inherited trait, I cannot think of any investigation that can be done.