Scientific Method Notes

The scientific method is a process that is used to find answers to questions about the world around us. There are several versions of the scientific method. Some versions have more steps, while others may have only a few. However, all versions begin with the identification of a problem or questions to be answered based on observations of the world around us and provide an organized method for conducting and analyzing an experiment.

Scientific Method Steps---

1. Identify the problem (purpose)

a)      What do you want to learn, know or explain?

b)      I wonder if…

c)      Ask a question about something that you observe: how, what, when, who, which, why, or where

d)      Use observations you have made to write a question that addresses the problem or topic you want to investigate.

2. Research the problem

a)      Find out information about your topic (plant growth, what do plants need to grow)

b)      Research about the materials you’ll be using (the type of plant you’ll be using, what type of plant fertilizer will be used, the ingredients in the fertilizer, how does a plant use sunlight to grow)

c)      Scientists use prior experience to make predictions about what will happen under certain circumstances

3. Make a hypothesis (educated guess)

a)      What do you think will happen? (If I place a plant in the closet, then it will grow at a slower rate than a plant on the windowsill.)

b)      Predict the answer to your question or the outcome of the experiment.

c)      This does not mean that it will be proven correct at the end of your experiment. It is simply an educated guess after doing your research.

4. Procedure or Experiment

a)      Design your experiment.

b)      How will you test your hypothesis? Develop a procedure for a reliable experiment and address safety rules.

c)      In a well-designed experiment, you need to keep all variables the same except for one.

1)      Experimental group—This group includes the part or parts of the experiment that are changed and tested. The results are then compared to the control group to determine what changes have taken place.

2)      Control group—This group includes the part or parts of the experiment that are left unchanged. The conditions a scientist wants to remain the same during the experiment are called constants.

3)      Control---factors that don’t change in the experiment (all plants get the same amount of water, container size, soil, and fertilizer)

4)      Variable—any factor that can change in an experiment

5)      Manipulated variable (independent variable)---the factor you change (amount of sunlight the plant receives)

6)      Responding variable (dependent variable)---the factor that changes as a result of the manipulated variable. The responding variable is what you measure or observe to obtain your results.   (the growth of each plant over a set period of time to determine the effects)

d)      List your materials—ALL materials including the measurements of items (4 meters, 24 kilograms, 7 liters, 2 drops of food coloring, 1 tablespoon of water)

e)      Write your steps in the order---just like a recipe.

5. Observe and record (results or analysis)

a)      Scientists use measurements and observations to assist them during an experiment.

b)      Observe everything—smell, sound, how much did it grow, how far did it fly, etc.

c)      Is the data reliable? Does your data and observations from the experiment support your hypothesis?

d)       IF your data is inaccurate or the experiment is flawed, then you need to modify the experiment and rewrite your procedure to address the flaws in the original experiment. Do the experiment again.

e)      Qualitative – describable, not measureable

1)      yellow flowers

2)      Smells like fresh baked cookies

3)      Tastes sour

f)        Quantitative –measurements or countable

1)      3 meters long

2)      6 marbles

3)      100 degrees Celsius

4)      25 kilograms

g)      Ways to record your results and observations

1)      Tables, charts, graphs

2)      Video or pictures

6. Conclusion—a statement that sums up what you have learned from the experiment

a)      How can you do the experiment differently?

b)      What did you learn?

c)      Do you have any new questions now that you have observed, recorded, and analyzed the results?

d)      Do you need to troubleshoot or change your design?

e)      Multiple trials are conducted so results are more reliable and valid. The same results must occur each time it is tested.

f)        Scientists communicate the results and conclusion to others through peer review such as scientific magazine or journal articles, seminars, and workshops.

Other key words to know---

       1. justify---show or prove to be right or reasonable; be a good reason for

 2. skepticism---to mistrust or doubt the results of an experiment

 3. inference---logical interpretation based on prior knowledge and experience

 4. bias---personal point of view that is not scientific

 5. theory---well-tested explanation that explains observations and hypotheses