Scientific MethodThe 7-step process to scientific The 7-step process to scientific

investigationsinvestigationsScientific methods are the ways in which Scientific methods are the ways in which scientists follow steps to answer questions scientists follow steps to answer questions and solve problems.and solve problems.

- - Life Science, Life Science, Holt, pg. Holt, pg. 1010

What is the Scientific Method?

The Scientific Method is a logical process used to find answers

to questions about the world around us.

Is there only one Scientific Method?

• No! There are several versions of this scientific process ranging in the number of steps.

• However, all versions begin with a question to be answered based on observations of the world around us and provide an organized method for conducting and analyzing an experiment.

Which version will we use?

We will be using a 7-step version in class with the following steps:

1. Observe and Question.2. Research the question.3. Form a hypothesis.4. Experiment and Observe.5. Analyze data.6. Draw Conclusions.7. Communicate results.

Do real scientists use this process?

• It’s important to note that even though many scientists do use the idea of the Scientific Method for their daily work, they do not necessarily use each of the individual steps.

• Also, a similar version of the Scientific Method has been adopted by businesses all over the country. It teaches employees and management to diagnose a problem, think about ways of solving that problem, then testing those ideas to try and solve the problem. It’s the same process but with a twist!

Step 1: Observe and Question or Establish the Problem

• What do you want to know or explain?

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

• Your investigation must be observable, measurable and repeatable.

What question would you ask if you found these frogs in a pond?

Question: Question: What’s causing frog What’s causing frog deformities in Minnesota?deformities in Minnesota?

Step 2: Research the question

• This is an important step, especially when you do an independent investigation such as a science fair project.

• Researching your question lets you know if others have done this same experiment before and if so, what their data suggests. If they had a widely accepted conclusion, you may want to try a different angle with your experiment or test a different variable.

• You should also research the scientific concepts associated with the experiment. For example, if you are testing to see which paper towel brand is the most absorbent, you should research absorbency, paper material, and quality control testing. This will help answer the “WHY?”

Where might you find information about the problem of frog deformities?

Internet Dept of Game and Inland Fisheries

(DGIF) Veterinarian Library

Step 3: Form a hypothesis A A hypothesishypothesis is a is a possible solution to a problem or question- anpossible solution to a problem or question- an

educated guess. educated guess.

#1 #1 The deformities were caused by chemical pollutants in The deformities were caused by chemical pollutants in the waterthe water

#2 The deformities were caused by attacks from parasites #2 The deformities were caused by attacks from parasites living on the frogsliving on the frogs

#3 The deformities were caused by an increase in #3 The deformities were caused by an increase in ultraviolet light from the sunultraviolet light from the sun

Before testing a hypothesis scientist Before testing a hypothesis scientist must make must make IF-THEN IF-THEN statementsstatements

Example:Example: IF IF a substance in the pond water is a substance in the pond water is

causing the deformities, causing the deformities, THEN THEN the water the water from ponds that have deformed frogs will from ponds that have deformed frogs will be different from ponds in which no be different from ponds in which no deformed frogs have been founddeformed frogs have been found..

Take a look at #’s 2 and 3 and form if-then statements

#2 The deformities were caused by attacks #2 The deformities were caused by attacks from parasites living on the frogsfrom parasites living on the frogs

#3 The deformities were caused by an #3 The deformities were caused by an increase in ultraviolet light from the sunincrease in ultraviolet light from the sun

Possible If-Then Statements

Hypothesis #2-

If a parasite is causing the deformities, then this parasite will be found more often in frogs that have deformities.

Hypothesis #3-

If an increase in exposure to ultraviolet light is causing the deformities, then some frog eggs exposed to ultraviolet light in a lab will develop into deformities.

Step 4: Experiment and Observe to test your hypothesis

• Design a procedure that tests your hypothesis to see if your prediction is correct.

• Record all of your data and observations and put them into a table that is neat and organized.

Controlled ExperimentControlled Experiment

An experiment which tests only An experiment which tests only oneone factor at a timefactor at a time and consists of a and consists of a control groupcontrol group and one or more and one or more

experimental groups.experimental groups.

Data Table

Step 5: Analyze data

• Is your data reliable? Does it make sense?

• Put your data into a chart or graph and look for any trends.

Pie Chart Line Graph Bar Graph

Multiple Trials

At this point it may be necessary to verify your conclusion by repeating the experiment. Each experiment completion is known as a trial.

Step 6: Draw conclusions

• Do your data and observations support your hypothesis?

• If you cannot make a definite conclusion, you may need to try the experiment again.

• This means you may either need to rewrite your procedure if it was not specific enough; you may find that your hypothesis was wrong.

Example:Example:

According to the research, prolonged exposure According to the research, prolonged exposure of frog eggs to UV light caused deformities in of frog eggs to UV light caused deformities in frogs.frogs.

Step 7: Communicate results• Report the results of your

experiment to let others know what you have learned.

• This will be represented as either a lab report, oral presentation, or Science Fair display board.

• Scientists may want to repeat your procedure to see if they get the same results as you. They may also tweak your experiment a little and have a slightly different focus.

• Also, your report may lead to a new question which may lead to another investigation. This of course brings us right back to the first step again!

One Last ThoughtOne Last Thought

If your hypothesis wasIf your hypothesis was wrong- wrong- IT’S OKIT’S OK! !

Proving a hypothesis wrong is still Proving a hypothesis wrong is still helpful- helpful-

either way either way something is learnedsomething is learned!!

What Did Thomas Edison Say?

..."I have not failed 700 times. I have not failed once. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."

Scientific Method

Any Any Questions?Questions?

!!

Experimental Design

HOW DO I

SET UP AN

EXPERIMENT?

Let’s take another look at our frog experiment

What Was Our Question? What Was Our Question?

What’s causing frog deformities in Minnesota?What’s causing frog deformities in Minnesota?

Our Hypothesis

If an increase in exposure to ultraviolet light is causing the deformities, then some frog eggs

exposed to ultraviolet light in a lab will develop into deformities

Controlled ExperimentControlled Experiment

An experiment which tests only An experiment which tests only oneone factor at a time and consists of a factor at a time and consists of a control groupcontrol group and one or more and one or more

experimental groupsexperimental groups..

GroupsGroups

Control Group- the group left the group left unchangedunchanged

Group with no Ultraviolet Light

Experimental Group- the group that the group that is changedis changed

Group with different amounts of UV

VariablesVariables things that are changedthings that are changed

Two Types:Two Types:

IndependentIndependent variable- the one thing you variable- the one thing you change in an experimentchange in an experiment

Amount of UV light

DependentDependent variable- what changes based on variable- what changes based on the independent variablethe independent variable

Amount of deformed frogs

Data Table

Data Table

Bar Graph

Other VocabularyOther Vocabulary

DataData- - pieces of information- may be pieces of information- may be kept in a logkept in a log

ControlsControls-- everything kept the same everything kept the same for each groupfor each group

SurveySurvey- - observation of many observation of many existing itemsexisting items

Whew!

That was A LOT!