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 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?????

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 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 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 HypothesisCan 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?A.Different amounts of sugar

B. 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?

A.How hot the oven isB.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 Can you think of some constants for this experiment?for this experiment?

ConstantsThey 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

Amt. of Sugar (g.)

1 2 3 Mean (cmMean (cm33))

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

Size of Bread Loaf (cmSize of Bread Loaf (cm33))

TrialsTrials

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.