Example of Scientific Method

Let’s put our knowledge of the Scientific Method to a realistic example that includes some of the terms you’ll need to use and understand.
Problem/Question
Jane watches her grandmother bake bread. She asks her grandmother what makes the bread rise.
She explains that yeast releases a gas as it feeds on sugar.
Jane wonders if the amount of sugar used in the recipe will affect the size of the bread loaf.
Observation/Research
Jane researches the areas of baking and fermentation and tries to come up with a way to test her question.
She keeps all of her information on this topic in a journal.
Jane talks with her teacher and she gives him a Experimental Design Diagram to help her set up her investigation.
Formulate a Hypothesis
After talking with his teacher and conducting further research, she comes up with a hypothesis.
“If more sugar is added, then the bread will rise higher.”
The hypothesis is an educated guess about the relationship between the independent and dependent variables.
The independent, or manipulated variable, is a factor that’s intentionally varied by the experimenter.
Jane is going to use 25g., 50g., 100g., 250g., 500g. of sugar in her experiment.
The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable.
In this case, it would be the size of the loaf of bread.
Experiment
Her teacher helps her come up with a procedure and list of needed materials.
She discusses with Jane how to determine the control group.
In a scientific experiment, the control is the group that serves as the standard of comparison.
The control group may be a “no treatment" or an “experimenter selected” group.
The control group is exposed to the same conditions as the experimental group, except for the variable being tested.
All experiments should have a control group.
Because her grandmother always used 50g. of sugar in her recipe, Jane is going to use that amount in her control group.
Jane’s teacher reminds her to keep all other factors the same so that any observed changes in the bread can be attributed to the variation in the amount of sugar.
The constants in an experiment are all the factors that the experimenter attempts to keep the same.
They might include:
Other ingredients to the bread recipe, oven used, rise time, brand of ingredients, cooking time, type of pan used, air temperature and humidity where the bread was rising, oven temperature, age of the yeast…
Jane writes out her procedure for her experiment along with a materials list in her journal. She has both of these checked by her teacher where she checks for any safety concerns.
Trials refer to replicate groups that are exposed to the same conditions in an experiment.
Jane is going to test each sugar variable 3 times.
Collect and Analyze Results
Jane comes up with a table she can use to record her data.
Jane gets all her materials together and carries out her experiment.
Size of Baked Bread (LxWxH) cm3
Size of Bread Loaf (cm3)
Trials

Amt. of Sugar (g.) 1 2 3 Average Size (cm3)
25 768 744 761 758
50 1296 1188 1296 1260
100 1188 1080 1080 1116
250 672 576 588 612
500 432 504 360 432

Jane examines her data and notices that her control worked the best in this experiment, but not significantly better than 100g. Of sugar.
Conclusion
Jane rejects her hypothesis, but decides to re-test using sugar amounts between 50g. and 100g.
Experiment
Once again, Jane gathers her materials and carries out her experiment.
Here are the results.
Size of Baked Bread (LxWxH) cm3
Size of Bread Loaf (cm3)
Trials
Amt. of Sugar (g.) 1 2 3 Average Size (cm3)
50 1296 1440 1296 1344
60 1404 1296 1440 1380
70 1638 1638 1560 1612
80 1404 1296 1296 1332
90 1080 1200 972 1084


Conclusion
Jane finds that 70g. of sugar produces the largest loaf.
Her hypothesis is accepted.
Communicate the Results
Jane tells her grandmother about her findings and prepares to present her project in Science class.