📊 Scientific Method & Data
What You'll Learn
- Apply the scientific method to a real question
- Distinguish independent, dependent, and controlled variables
- Read and create a basic bar graph from experimental data
Variables in an Experiment
Every controlled experiment has three types of variables:
- Independent variable — what you intentionally change (the input)
- Dependent variable — what you measure as a result (the output)
- Controlled variables — everything else you keep the same so they don't affect results
Example: Testing how fertilizer amount affects plant height.
Independent = amount of fertilizer | Dependent = plant height | Controlled = pot size, soil type, sunlight, water
If you changed two things at once, you wouldn't know which one caused the result. Changing only one variable at a time is what makes science reliable and repeatable.
Reading Data & Graphs
Scientists record data in tables, then visualize it in graphs to spot patterns. A bar graph compares discrete categories. A line graph shows change over time. A scatter plot shows relationships between two continuous variables.
📊 Virtual Lab: Plant Growth Data
Enter your measurements for 5 plants that received different amounts of fertilizer. The bar graph updates live!
In an experiment on how temperature affects reaction speed, the temperature is the:
Why must all variables except one be kept the same?