What Do I Do With My Data?
Once your experiment is done, the next step is making sense of what you collected. Here's how to turn raw numbers and observations into clear, meaningful results.
Qualitative vs. Quantitative Data
Every science fair project produces two kinds of data. Knowing which kind you have helps you decide how to record and analyze it.
- Quantitative data comes from measurements and counts — numbers with units, like height in centimeters or temperature in degrees.
- Qualitative data comes from observations you describe in words, like color changes, texture, or behavior.
Strong projects usually include both, but quantitative data is what lets you build the kind of graphs and tables that judges look for.
Identifying Your Variables
Before you graph anything, label each column of your data table so the story is obvious at a glance.
| Variable Type | What It Means | Example |
|---|---|---|
| Independent | What you change on purpose | Amount of sunlight a plant receives |
| Dependent | What you measure as a result | Height of the plant after one week |
| Controlled | What you keep the same | Type of plant, amount of water, pot size |
Putting the independent variable on the x-axis and the dependent variable on the y-axis is the standard setup for a line graph.
Graphing 101
Line Graphs
Line graphs are the best choice when your independent variable is continuous — think time, temperature, or distance. They make trends easy to see, like a steady rise, a dip, or a flat line.
Bar Graphs
Use a bar graph when your independent variable is made of separate categories, such as three different brands of paper towel or four kinds of soil. Each bar stands on its own.
Common Mistakes to Avoid
- Forgetting to label axes or include units.
- Skipping a title that states the main finding.
- Stretching or squashing the scale so a small change looks huge.
Interpreting Your Results
Once your graph is drawn, write a short paragraph that answers three questions in plain language: What did you expect, what actually happened, and why might that be?
If the result surprised you, that is worth noting too. Unexpected findings often lead to the most interesting conversations with judges and are a sign that you really ran the experiment yourself.
Keep Going
Once your data is organized and graphed, you are ready to put the whole story together. These next pages walk through the rest of the process.