Scientific Methods

Scientific Methods Steps to Answering Questions & Solving Problems

Step 1: Ask a Question -Questions come from careful observations. -made using 5 senses. -Begin with: how, which, why, where, what, who. -NOT a question answered by Yes/No. __________________________________________

Step 1: Ask a Question -Questions come from careful observations. -made using 5 senses. -Begin with: how, which, why, where, what, who. -NOT a question answered by Yes/No. __________________________________________ -On your CPS: Which of these is a good example of a question to ask? A. Does sunshine affect paint? B. What is the effect of sunshine on paint?

Step 2: Hypothesis -Hypothesis – your “educated guess” to answer question. What you think outcome of experiment will be. -must be testable. -stated in “if-then” format. -ex: If painted board is left in sunshine for 1 week, then it will be faded.

Step 3: Experiment (Test Hypothesis) -Identify variables. -independent variable – factor YOU change in order to see its affect. -dependent variable – factor being measured. -Test only 1 independent variable at a time. -Keep everything else the same (constants). -Establish a control – standard for comparison. -Write down detailed materials & procedures. -More than 1 trial needed……why?????

Experiment, cont. -On your CPS: -In our paint experiment, which factor is the dependent variable? A. condition of the paint B. exposure to sunshine __________________________________________ -Condition of paint depends on exposure to weather. -dependent – condition of paint. -independent – exposure to sunshine. -How will we establish a control? -What will we need to keep constant between the two?

Step 4: Analyze Results -Organize data with tables or graphs. -Study carefully before making a conclusion. Pie Chart Bar Graph Line Graph Data Table

Step 5: Draw Conclusion -Does the data support your hypothesis or not? -Suggestions for improvement of experiment. -If data does NOT support hypothesis, does that mean hypothesis is not valuable?

Step 6: Communicate Results -Share results through reports (written or presented). -Why do you think this is important?

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

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

Question John wonders how the amount of sugar used in the recipe will affect the size of the bread loaf?

Formulate a Hypothesis Can you think of one? “If more sugar is added, then the bread will rise higher.” He decides to design an experiment to test if different amounts of sugar will affect the size of the bread.

Independent Variable The independent variable is a factor that’s intentionally varied by the experimenter. On your CPS: what is the independent variable for his experiment? • Different amounts of sugar • Size of the loaf of bread

Dependent Variable The dependent variable is the factor being measured as a result of changes made in the independent variable. On your CPS: what is the dependent variable for his experiment? • How hot the oven is • The size of the loaf of bread

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.

Control 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.

Control Group What is control for his experiment? Because his grandmother always used 50g. of sugar in her recipe, John is going to use that amount in his control group.

Constants John needs 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.

Can you think of some constants for this experiment?

Constants 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…

Experiment John writes out his procedure for his experiment along with a materials list in his journal.

Trials Trials refer to replicate groups that are exposed to the same conditions in an experiment. John is going to test each sugar variable 3 times.

Collect and Analyze Results John comes up with a table he can use to record his data. John gets all his materials together and carries out his experiment.

Size of Baked Bread (LxWxH) cm3 Size of Bread Loaf (cm3) Trials Control group

Collect and Analyze Results John examines his data and notices that his control worked the best in this experiment, but not significantly better than 100g. of sugar.

Conclusion John decides that his data does not support his hypothesis.

Communicate the Results John tells his grandmother about his findings and prepares to present his project in Science class.

Scientific Methods