Independent Dependent Variables What is Cause and Effect

Independent & Dependent Variables

What is “Cause” and “Effect”? • CAUSE - something that makes something else happen - happens first • EFFECT - what happens as result of the cause - happens second or last

Cause The boy kicked the ball. Effect The ball rolled. Sam slept late last night. Sam was tired today. It rained all day. The streets were wet.

• In a experiment, there are 2 variables: 1. Independent Variable 2. Dependent Variable • There is also a CONTROL group - the control group does not change - used to compare to experimental group

What are IV’s and DV’s? • IV’s are the CAUSE – experimental changes • DV’s are the EFFECT – what happens in response to IV * The IV will cause the DV to change.

Independent Variable Dependent Variable Minutes used Cell phone bill The amount of gas you have How far you can drive The hours you work How much money you make Your grade How hard you work

How does the IV & DV relate to the hypothesis? • The IV can be found in the “IF” statement • The DV can be found in the “THEN” statement

Example… • IF I wear a black shirt on one day and a white shirt on another day, IV = color of shirt THEN I will be hotter on the day I wear the black shirt DV = temperature BECAUSE black attracts heat ** so… temperature depends on color of shirt

Control Group • Example of 2 plants • Want to see if fertilizer will help it grow faster • What do you compare it to? • Put fertilizer in one, and leave on alone • Control group = group that does not change; you don’t do anything to it

Examples 1. The higher the temperature of water, the faster the egg will cook. The _______ causes the _______ to change. IV: ____ DV: ____

2. The time it takes to run a mile depends on the amount of exercise a person gets. The ____ causes the ____ to change. IV: ______ DV: _____

3. The amount of time you study affects the grade you get on a test. The ____ causes the _______ to change. IV: ______ DV: ______

4. The amount of cavities you get depends on how often you brush your teeth. The ____ causes the ____ to change. IV: ______ DV: ______