The Scientific Method

The Scientific Method • What is it? • Who uses it? • Why should I care?

Everyone uses it everyday! • Yes! Even you!

It is a way to solve problems! BIG or small

Any of these sound familiar? • Where are my shoes? • What class do I have next? • How do I solve that math problem? • Which deodorant works the best? • Which pain reliever works the best? • What is the cure for cancer?

There are SIX steps to the Scientific Method: • Problem/Question • Information/Research • Hypothesis • Experiment • Observations/Analysis • Conclusion

By following these steps in order, you will learn about your problem. • Notice the IN ORDER part. It is very important!

1. Problem/Question • This is the problem you are trying to solve or the question you are trying to answer. • Try to narrow it down and be specific.

2. Information/Research • Has someone tackled this problem before? • If not, gather information about your question/problem: • books • magazines • experts • past experiences

2. Information/Research • Valid Internet sites • Check date when site was last updated • Who put the page together? • Who is responsible for the information?

3. Hypothesis • The hypothesis is an educated guess about the relationship between the independent and dependent variables. • This is what you think the answer is based upon the information you gathered • It should be in form “If (independent), then (dependent).

3. Hypothesis • Independent Variable • The independent, or manipulated, variable is a factor that is intentionally varied by the experimenter. • Dependent Variable • The dependent, or responding, variable is the factor that may change as a result of the changes made to the independent variable. • This is the expected outcome!

4. Experiment • The actual experiment is broken into two parts: • Materials • A list of equipment that you will need for the experiment. • Procedure • A list of instructions that you need to follow for the experiment. (Should be detailed!)

4. Experiment • 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.

4. Experiment • Constants • The constants in an experiment are all of the factors that the experimenter attempts to keep the same. • Trials • Trials refer to the replicate groups that are exposed to the same conditions in an experiment. • You should do a minimum of 3 trials.

5. Observations/Analysis • Observations • Collection of information and data from the experiment. • It may be in the form of charts, graphs, or written work. • This is WHAT HAPPENED!

5. Observations/Analysis • Analysis • This is an explanation of your observations. • It may involve analyzing your graphs or charts in order to look for patterns to help you answer your question. • It can even mean putting your measurements into a mathematical equation to get an answer.

6. Conclusion • What did you find the answer to your was? • It should state whether you accept or reject your hypothesis. • This does not necessarily mean you “proved” something--just that your analysis supports your hypothesis. • It is OK if it turns out your hypothesis is not correct. You learned!!!!!! • It may lead to another experiment.

Report Your Findings! • Something that is very important but not officially part of the scientific method is to report to others your findings. • You will help others learn!

Common Mistakes • Do not change your hypothesis throughout the experiment. • Do not rule out and ignore observations and data that do not support your hypothesis.

Let’s put our knowledge of the Scientific Method to a realistic example that includes some of the terms you’ll be needing to used and understand.

Problem/Question • John watches his grandmother bake bread. He asks her what makes the bread rise. • She explains that yeast releases a gas as it feeds on sugar.

Problem/Question • John wonders if the amount of sugar used in the recipe will affect the size of the bread loaf.

Information/Research • John researches the areas of baking and fermentation and tries to come up with a way to test his question.

Hypothesis • After talking with his teacher and conducting further research, John comes up with a hypothesis: • If more sure is added, then the bread will rise higher.

Variables • Independent Variable • John is going to use 25 g, 50 g, 100 g, 250 g, and 500 g of sugar in his experiment. • Dependent Variable • The size of the bread loaf.

Control Group • Because his grandmother always uses 50 g of sugar, John is going to use that amount in his control group.

Constants • other ingredients to the bread recipe • brand of ingredients • rise time • air temperature and humidity where the bread is rising • type of pan used • oven used • cooking time

Experiment • John writes out his materials and procedure for his experiment in his journal. Trials • John is going to test each sugar variable 3 times.

Observations/Analysis • John comes up with a table so that he can record his data. • John gets all of his materials together and carries out his experiment.

Size of Bread Loaf (cm3) Trials Observations/Analysis

Observations/Analysis • John examines his data and notices that his control group worked the best in his experiment, but not significantly better than 100 g of sugar.

Conclusion • John rejects his hypothesis, but decides to re-test using sugar amounts between 50 g and 100 g.

Size of Bread Loaf (cm3) Trials Observations/Analysis

Conclusion • John finds that 70 g of sugar produces the largest loaf. • He accepts his new hypothesis.

The Scientific Method