Catalyst
You are performing an experiment where you test how hydrogen gas reacts with three different elements: oxygen, nitrogen, and carbon.
Independent and Dependent Variables
Quick Experiment
If I choose one guy and one girl at random in the class, then the girl will have more jewelry than the guy because most girls like jewelry.
What Just Happened?
What did we change?
The gender of the volunteer
What did we observe?
The amount of jewelry being worn
Independent and Dependent Variables
Independent Variable:
The variable that you CHANGE
Dependent Variable:
The variable that you observe and measure the RESULT of
Example-Plants and Sunlight
Question: Do plants need the sun in order to grow?
Hypothesis: If there is an absence of sunlight, then plants will not grow because plants need sunlight to grow.
What are the variables?
Independent Variable: (what are we changing?)
Sunlight
Dependent Variable: (what are we measuring?)
Plant Growth
Example-Plants and Fertilizer
You observe that plants that are fed fertilizer grow to be very tall.
Question: Does fertilizer make plants grow taller?
Independent Variable:
Fertilizer
Dependent Variable:
Plant Height
Example-Rain and Zebras
Observation: A scientist studied the relationship between the amount of rain and the number of zebras born each spring.
Independent Variable:
Amount of rain
Dependent Variable:
Number of zebras born
Graphing Data
After collecting data, you need to make graphs in order to interpret the result
MIX DRY
Manipulate Independent Variable X-Axis
Dependent Responsive Variable Y-Axis
Create a Graph with the Data
Hours Studied | Grade on Test |
2 | 2.85 |
.5 | 1.9 |
3 | 3.15 |
2.5 | 3.28 |
6 | 3.6 |
Design an Experiment
Mr. Adato observes that his smaller classes seem to do better on tests than his larger classes. If he were to design an experiment to test whether class size affects test grades, what would the independent variable be? What would the dependent variable be?
Independent Variable
Class size
Dependent Variable
Test Scores