Scientific Scientific MethodMethod

Vocabulary to Know:Vocabulary to Know:• Basics on Scientific Method• Variable• Control

ScienceScience• Science and nature follow a set of

rules which govern the way things work.– Gravity is an example.

• Science explanations can be changed over time. Why do you think this is possible?

It’s a lot of work- Why? It’s a lot of work- Why? • We spend time teaching, using and

reviewing the scientific method because:– It makes you think– It asks you to predict – It makes you practice being careful and

organized– It helps to make the content relevant to your

world beyond school– It combines your previous knowledge and

experiences with new content

Keep in mind the big pictureKeep in mind the big picture• We will DO science (experiments and

observations)• We need to make sure this science is

valid and repeatable• We also need to make sure we can

communicate what we did and what we learned

• These are the true reasons for the way we do the scientific method and their write-ups

Using the scientific method Using the scientific method requires that one be a good requires that one be a good

observer. observer.

observation inference

involves a judgmentor assumption

uses the fivesenses

Scientific MethodScientific Method• The scientific method is an organized

set of investigation procedures used by scientist when experimenting.

• The are six general steps for the scientific method.

• Don’t think of them necessarily as steps, though. You can always go back and repeat…

6 General Steps of the 6 General Steps of the Scientific MethodScientific Method

1. State the Problem2. Gather information3. Form a hypothesis4. Test the hypothesis5. Analysis data6. Draw conclusions

Stating a ProblemStating a Problem• Begin with a general observation in

your surroundings.• Ask a “why” question about

something that you see.• State the problem.

Researching and Researching and Gathering InformationGathering Information

• Do some research on your problem…do a background check.

• You need to have a basic understanding of the topic that you are investigating.

Form a hypothesisForm a hypothesis• A hypothesis is a possible

explanation for a problem using what you know and what you observe.

• This is what you think will happen when you do your experiments.

• You will test your hypothesis.• Example: If soil temperatures rise,

then plant growth will increase.

Test the hypothesisTest the hypothesis• Test your hypothesis through

experimentation.• The most common way to test a

hypothesis is through the use of an experiment—this tests the effect of one thing on another using controlled conditions.

ExperimentsExperiments• When doing a experiment you will

need to think of all of the factors that will effect the overall experiment

• Experiments contain at least 2 variables.

Variables of an ExperimentVariables of an Experiment– A variable is a quantity that can have

more than a single value.•Dependent variable: value changes

according to the changes in other variables•Independent variables: Variable YOU

change to see how it will affect the dependent variable

– If I have 2 plants, but I only water one for 3 months I think the watered plant will grow bigger because plants need water to grow.

Experiments ContinuedExperiments Continued

• Another key factor to doing an experiment is having a control and a constant.– A control is the standard by which

the test results can be compared.– A constant is a factor that does not

change when other variables are changed.

DataDataObservations are also called Observations are also called datadata..

There are two types of data.

qualitative data quantitative data

descriptions; measurements; no numbers must have numbers

Include tables, graphs, and

photographs.

Analysis of DataAnalysis of Data• Always record what you observe and

organize these observations.• If a scientist doesn’t record what he

did, than what proof does he have of what he did?

• Use graphs and tables to display your observations.

• Be ORGANIZED!

Draw ConclusionsDraw Conclusions• From the review of your data, decide

whether or not your hypothesis was correct or incorrect.

• Repeat the experiment if correct or revise if necessary.

• Be careful of bias: what a person expects changes how the results are viewed

Non-Scientific Uses of the Non-Scientific Uses of the Scientific MethodScientific Method

Using a recipe to cook supperAdvertising: Trial and ErrorSportsWriting a news storyFinancesEtc.

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.

Problem/QuestionProblem/QuestionJohn watches his

grandmother bake bread. He ask his grandmother what makes the bread rise.

She explains that yeast releases a gas as it feeds on sugar.

Problem/QuestionProblem/Question

John wonders if the amount of sugar

used in the recipe will affect the size of the bread loaf?

Caution!Caution!Be careful how you use effect and

affect.Effect is usually a noun and affect,

a verb.“ The effect of sugar amounts on

the rising of bread.”“How does sugar affect the rising

of bread?”

Observation/ResearchObservation/ResearchJohn researches the areas of baking and

fermentation and tries to come up with a way

to test his question.He keeps all of his information on this topic in a journal.

ReferencesReferencesHow Scientists Work: What is the Scientific Method?.

United Learning (2003). Retrieved January 3, 2006, from unitedstreaming:

http://www.unitedstreaming.com/ Methods of Science. Glencoe Science: Physical Science

(2002).Powerpoint obtained from:

http://www.unit5.org/christjs/Intro%20to%20Chem/The%20Scientific%20Method.ppt on August 20, 2008