The Scientific The Scientific MethodMethod

What is Science?What is Science?

Study of the natural and physical Study of the natural and physical world based on facts learned world based on facts learned through experiment and through experiment and observation.observation.

Physical SciencePhysical Science

The scientific study of The scientific study of non-livingnon-living matter.matter. ChemistryChemistry

The study of composition, structure, The study of composition, structure, properties and change of properties and change of matter.matter.

PhysicsPhysics The study of matter, energy and the The study of matter, energy and the

interaction between them. interaction between them.

Scientific MethodScientific Method

Step-by-step way in which scientists Step-by-step way in which scientists answer questions.answer questions.

1. Ask a 1. Ask a questionquestion..2. 2. ResearchResearch the topic. the topic.3. Form a 3. Form a hypothesis.hypothesis.4. 4. Test Test the Hypothesis.the Hypothesis.5. Gather 5. Gather DataData..6. Analyze 6. Analyze Results.Results.7. Draw 7. Draw Conclusions.Conclusions.8. Communicate 8. Communicate Results.Results.

1. State the Problem/Ask a Question

The problem identifies what you want to find out.

Develop a clear statement defining the problem

Make sure your problem is narrowed/specific enough.

State the problem in the form of a question.

2. Research

Write down all information you already know

Do research in books/internet on the topic you are investigating

Record the information you discover

3. Hypothesize3. Hypothesize

An An explanationexplanation that is based on that is based on prior scientific research or prior scientific research or observations and that can be tested.observations and that can be tested.

““EducatedEducated Guess” Guess” ““If… then… because” StatementIf… then… because” Statement

4. Test Hypothesis4. Test Hypothesis

Develop a test to support or not support your hypothesis. (This is your experiment). Will usually be run multiple times Must have only 1 independent

variable (the factor being tested)

……test hypothesis test hypothesis continuedcontinued Use a Controlled Experiment Use a Controlled Experiment

An experiment that tests only An experiment that tests only one one factor at a factor at a time by using a comparison of a control group time by using a comparison of a control group and an experimental group.and an experimental group.

Control GroupControl Group The group that the scientist changes The group that the scientist changes nothingnothing

in. The Control group is used for comparison. in. The Control group is used for comparison. Experimental GroupExperimental Group

The group that the scientist has changed The group that the scientist has changed something. It is the something. It is the variablevariable in the in the experiment where you want to see how this experiment where you want to see how this condition affects something.condition affects something.

What is a variable?What is a variable? A variable is something that is able A variable is something that is able

to change, either naturally or on to change, either naturally or on purpose. purpose. Independent VariablesIndependent Variables Dependent VariablesDependent Variables

Two Types of VariablesTwo Types of VariablesIndependentIndependent

variables that are variables that are purposely changed or purposely changed or manipulated in an manipulated in an experiment experiment

the factor that you wish to the factor that you wish to testtest

usually expressed after usually expressed after the word “if” in the the word “if” in the hypothesishypothesis

could be thought of as the could be thought of as the “cause” in a cause and “cause” in a cause and effect relationshipeffect relationship

ExampleExample

The activity level (resting, The activity level (resting, walking, running) walking, running)

DependentDependent

variables that may change variables that may change as a result of the as a result of the independent variableindependent variable

the factor you measure to the factor you measure to gather resultsgather results

usually expressed after the usually expressed after the word “then” in the word “then” in the hypothesishypothesis

could be thought of as the could be thought of as the “effect” in a cause and “effect” in a cause and effect relationshipeffect relationship

ExampleExample

The person’s heart rateThe person’s heart rate

Identify the VariablesIdentify the Variables

1.1. If a student chooses to not study, then If a student chooses to not study, then they will earn a poor grade.they will earn a poor grade.

2.2. If you drink Gatorade before a soccer If you drink Gatorade before a soccer game, then you will score more goals.game, then you will score more goals.

3.3. If you increase the mechanical If you increase the mechanical advantage of a pulley system used to advantage of a pulley system used to move an object, then the input force move an object, then the input force becomes less.becomes less.

independent variable

dependent variableindependent

variable

dependent variableindependent

variable

dependent variable

What are constants?What are constants?

They are what the scientist kept the They are what the scientist kept the samesame in both the control group and in both the control group and the experimental group.the experimental group.

5. Gather Data5. Gather Data Make Make Observations.Observations.

Any use of the senses to gather information.Any use of the senses to gather information. Qualitative Qualitative ObservationsObservations

Anything that you see, smell, touch, taste, or hear.Anything that you see, smell, touch, taste, or hear. Ex. Blue, bitter, fizzing sound.Ex. Blue, bitter, fizzing sound.

QuantitativeQuantitative Observations Observations Any observation that can be measured.Any observation that can be measured. Must include a number.Must include a number. Ex. 5 centimeters longEx. 5 centimeters long

Record Data Write observations and measurements Be consistent when you are checking your

experiments and recording the results Create tables or charts (Data Tables and Pie Charts)Data Tables and Pie Charts)

Observe Yourself!Observe Yourself!

Identify 5 qualitative and 5 Identify 5 qualitative and 5 quantitative facts about yourself. quantitative facts about yourself.

Qualitative Quantitative

Observation vs. InferenceObservation vs. Inference

Observation – what you noticeObservation – what you notice Inference – reactions, thoughts or Inference – reactions, thoughts or

explanations.explanations.Make one inference and oneobservation based off of the picture to the left.

6. Analyze Results6. Analyze Results Create graphs from collected Data

(Line Graphs, Bar Graphs)Line Graphs, Bar Graphs) Complete all necessary

mathematical calculations

7. Draw 7. Draw conclusionconclusion

ss Answer the Answer the

following following questions in questions in paragraph paragraph form (Always form (Always explain in explain in detail using detail using scientific scientific vocabulary.):vocabulary.):

http://guides.lib.purdue.edu/content.php?pid=232776&sid=1925925

What is in a conclusion?What is in a conclusion? Restate the basics of your experiment, including what you Restate the basics of your experiment, including what you

were trying to accomplish or prove. (refer to the purpose were trying to accomplish or prove. (refer to the purpose and restate your hypothesis)and restate your hypothesis)

Reference some specific results (you do not have to give Reference some specific results (you do not have to give detail on every single result, but use some of them as detail on every single result, but use some of them as examples in your explanation)examples in your explanation)

What flaws have occurred or could have occurred? Here, you What flaws have occurred or could have occurred? Here, you want to state variables that could have impacted your results.want to state variables that could have impacted your results.

Sum it up! Sum up your conclusion and reveal whether your Sum it up! Sum up your conclusion and reveal whether your experiment supported or disproved your hypothesis. experiment supported or disproved your hypothesis.

Implications! Use your results to explain how this Implications! Use your results to explain how this experiment could be used in future studies or research (apply experiment could be used in future studies or research (apply it to real life situations). it to real life situations).

Read it out loud! You want to confirm that it all makes sense! Read it out loud! You want to confirm that it all makes sense! Check your grammar and punctuation! Check your grammar and punctuation!

Let’s try!Let’s try!After reading the story examine how the scientific After reading the story examine how the scientific

method is used to solve the problem presented. Answer method is used to solve the problem presented. Answer the questions in your notebook in complete sentences.the questions in your notebook in complete sentences.

1. What is the problem? 1. What is the problem? 2. What is the hypothesis? 2. What is the hypothesis? 3. Describe how the experiment was set up?  3. Describe how the experiment was set up?   4. Which group was the control group? The experimental group?  4. Which group was the control group? The experimental group?  

Control:Control: Experimental:Experimental:

5. Why give that antibiotic to a small group of people first? 5. Why give that antibiotic to a small group of people first? 6. What is the independent variable in this experiment? (Which 6. What is the independent variable in this experiment? (Which

factor is being tested?)factor is being tested?) Independent Variable:  Independent Variable:  

7. What is the dependent variable in this experiment? (Which 7. What is the dependent variable in this experiment? (Which factor is being measured/observed?)factor is being measured/observed?) Dependent VariableDependent Variable

8. How could this experiment have been designed better?8. How could this experiment have been designed better? Bonus: What is the reason for using a placebo?Bonus: What is the reason for using a placebo?

What is the difference What is the difference between a scientific theory between a scientific theory

and a scientific law?and a scientific law? TheoryTheory

An explanation that An explanation that ties ties together many together many hypotheses and hypotheses and observations.observations.

Supported by Supported by repeated repeated trials.trials.

May help with May help with further predictions.further predictions.

Tells Tells whywhy it it happens.happens.

LawLaw A sA summary ummary of of

many experimental many experimental results and results and observations.observations.

TellsTells how how things things workwork

Only tells what Only tells what happens, it does happens, it does not not explain why.explain why.