After you finish your experiment and record your results, make sure to organize them well. This not only makes a good impression on judges, but also helps you see what you did clearly. Once you have your data together, you need to decide if the results support your hypothesis or not. If they don't, you should explain why. Think about why this might be and use your data to support your reasons.

Make sure to spend enough time analyzing the data and results of your experiment. Many scientists find it helpful to use tables, charts, and graphs to show the data from the experiment visually. You can use Microsoft Excel or Google Docs (Spreadsheet) to do this easily. Remember to include the unit of measurement in your tables and graphs.

If you repeated the experiment a few times (you should usually do this at least three times), a table or chart can be a good way to show and explain your data. You might also want to include the average measurements.

For graphs, it's usually best to put the independent variable on the X-axis and the dependent variable on the Y-axis. In our example, the independent variable is the SPF rating and the dependent variable is the UV index (UV reading). We used a different color for each SPF rating, but used the same color for that rating no matter what brand of sunscreen we used. There are different types of graphs that you can use, but the most common and effective ones are bar charts and line graphs.

What to do if the results do not support your hypothesis

A scientist never gives up, even when the results of the experiment do not support his or her hypothesis! A scientist realizes that experiments with negative results are just as important as experiments with positive results - because they both provide objective, valid information about the topic that is being researched. You will notice that in some of the science projects contained on this website, some of them actually have a hypotheses that were rejected. Again, that's perfectly acceptable and the science fair judges will not penalize you for failing to prove your hypothesis.

What should you do if the results do not support your hypothesis?

Do not change your hypothesis, even if you are tempted to do so. Instead, you should provide possible explanations of why the results do not support your hypothesis. You should also suggest an alternative experiment to solve your "problem".

What to do if the results support your hypothesis?

If the results do support your hypothesis, you should then summarize your findings in a short, clear narrative. Here, you should also re-state the problem, the hypothesis and some ways you can improve your experiment. In the example above, you could say:-

• My hypothesis is that Sunscreen lotions with a higher SPF rating are able to block a larger amount of UV radiation from the sun, and therefore provide better protection.
• My experiments show sunscreen lotions with a higher SPF rating does in fact block larger amounts of UV radiation, but only up to a certain point. I discovered this by testing how much UV radiation was blocked by sunscreen lotions with various SPF levels. We tested lotions with SPF 15, 30 and 50, and also performed a control experiment with no sunscreen lotion. Increasing the SPF level from 15 to 30 resulted in a lower UV radiation reading. However, increasing the SPF level from 30 to 50 did not result in a further reduction in UV radiation.
• I performed my experiment with 5 brands of sunscreen lotion.
• To improve on my experiment, I would try the same process using a UV lamp instead, for a more constant/stable source of UV radiation.