Scientific Scientific MethodMethod

S. DickinsonS. Dickinson

BiologyBiology

2011-20122011-2012

In your notes, write about what you In your notes, write about what you think of this picture.think of this picture.

Think-pair-shareThink-pair-share

Get with a neighbor and share Get with a neighbor and share what you wrote in your noteswhat you wrote in your notes

Share with the classShare with the class

What do you think What do you think the first part of the the first part of the Scientific Method Scientific Method is?is?

What do you think the question was in What do you think the question was in this experiment?this experiment?

What will you use for comparison?What will you use for comparison?

Scientific MethodScientific Method

Certain methods to obtain Certain methods to obtain knowledgeknowledge

Ask questions… and then what?Ask questions… and then what? 7 Steps7 Steps Have you ever asked who, what, Have you ever asked who, what,

where, when, how, or why? where, when, how, or why? That’s the beginning.That’s the beginning.

What was the question?What was the question?

Formulate a hypothesis. Write it in your Formulate a hypothesis. Write it in your notes.notes.

What is changed on purpose?What is changed on purpose?

Steps in the Scientific Steps in the Scientific MethodMethod1.1. Use observations to identify a Use observations to identify a

problemproblem

2.2. Formulate a hypothesisFormulate a hypothesis

3.3. Construct a procedure (step by step Construct a procedure (step by step directions)directions)

4.4. Conduct your experimentConduct your experiment

5.5. Collect and analyze dataCollect and analyze data

6.6. Draw a conclusionDraw a conclusion

7.7. RepeatRepeat

Step 1: Use observations to Step 1: Use observations to identify a problemidentify a problem

ObservationObservation Employs one or more of the 5 Employs one or more of the 5

sensessenses Direct or indirectDirect or indirect

Can you use your senses directly to Can you use your senses directly to study electricity?study electricity?

Step 2: Formulating a Step 2: Formulating a HypothesisHypothesis Testable statementTestable statement Evidence does or does not support the Evidence does or does not support the

statementstatement IF (put independent variable here), IF (put independent variable here),

THEN (put dependent variable here) THEN (put dependent variable here) statementstatement If the virus causes a deadly disease then If the virus causes a deadly disease then

introducing that virus into healthy tissue will introducing that virus into healthy tissue will cause the tissue to die.cause the tissue to die.

Rewrite your former hypothesisRewrite your former hypothesis Not all hypotheses are in If, then format.Not all hypotheses are in If, then format.

Independent vs. Independent vs. DependentDependent

Independent is Independent is manipulated variable manipulated variable (what you change) (what you change) - - ex. Light exposure, food, ex. Light exposure, food, time, depth, scent, etc.time, depth, scent, etc.

Dependent is Dependent is responding variable responding variable (DATA) (DATA) (what happens (what happens due to the change) - ex. due to the change) - ex. Height, growth, amount Height, growth, amount of oxygen produced, etc.of oxygen produced, etc.

REMEMBER:REMEMBER:

D – dependentD – dependent

R – respondingR – responding

Y – axisY – axis

M – M – manipulatedmanipulated

I – independentI – independent

X – axisX – axis

Step 3: ProcedureStep 3: Procedure

Step by step directions that are Step by step directions that are self self explanatoryexplanatory

Number your stepsNumber your steps Be specific about equipment, Be specific about equipment,

amounts, units, etc… but not wordyamounts, units, etc… but not wordy

Step 4: ExperimentingStep 4: Experimenting Testing a hypothesis by Testing a hypothesis by

gathering data under gathering data under controlled conditionscontrolled conditions

Controlled ExperimentControlled Experiment You change You change oneone factor or factor or

variablevariable and observe its and observe its effect on another while effect on another while keeping all other factors keeping all other factors the same or constantthe same or constant

Experimenting cont…Experimenting cont…Constant:Constant: variables that stay the same variables that stay the same

through out the experimentthrough out the experimentex. Same amount of water in all beakers, ex. Same amount of water in all beakers, same sized beakers, same plants…same sized beakers, same plants…

Control:Control: a sample that is treated like the a sample that is treated like the other experiment groups but the other experiment groups but the independent variable isn’t appliedindependent variable isn’t applied (what (what normally takes place)normally takes place)ex. You are testing a new drug. One group ex. You are testing a new drug. One group received the drug; the other group was a received the drug; the other group was a placebo (sugar pill). The group given the placebo (sugar pill). The group given the placebo is the control group.placebo is the control group.

ScenariosScenarios As a group, analyze the scenarios to As a group, analyze the scenarios to

come up with:come up with:What is the question being raised?What is the question being raised? Independent Variable?Independent Variable?Dependent Variable?Dependent Variable?Control?Control?Constant(s)?Constant(s)?Write a hypothesis based on the Write a hypothesis based on the

scenario.scenario.

How do you collect data on this How do you collect data on this experiment?experiment?

Will it be the same for all experiments?Will it be the same for all experiments?

Step 5: Collecting and Step 5: Collecting and analyzing dataanalyzing data

Forms of Data Collection:Forms of Data Collection:1. Measuring1. Measuring Quantitative data: data is measured in Quantitative data: data is measured in

numbersnumbers Number of people in a groupNumber of people in a group Measurements of a cubeMeasurements of a cube Duration of an eventDuration of an event

2. Sampling2. Sampling Using a small part to represent an entire Using a small part to represent an entire

populationpopulation Must be large and randomMust be large and random Should include as many subjects as possibleShould include as many subjects as possible

Forms of Data Collection cont…Forms of Data Collection cont…

33. Organizing Data. Organizing Data Data is useless unless its organizedData is useless unless its organized

Data table, graphs, chart, Data table, graphs, chart, concept map (appendix A)concept map (appendix A)

Analyzing DataAnalyzing Data

Process of Process of determining whether datadetermining whether data you collected you collected is reliableis reliable and if it and if it supports your hypothesis or notsupports your hypothesis or not

Data can be analyzed in several waysData can be analyzed in several ways Statistics to determine a relationship Statistics to determine a relationship

between the variablesbetween the variables Compare the data with those obtained in Compare the data with those obtained in

other trials or studiesother trials or studies Determine sources of errorDetermine sources of error

Analyzing Data cont.Analyzing Data cont. Data analysis shows general or specific Data analysis shows general or specific

trends or patterns from a graph that you trends or patterns from a graph that you have created from your data chart or table.have created from your data chart or table.

General Trend:

From 1955 to 1995, the total amount of ozone decreased from 325 d.u. to 169 d.u. in Antarctica.

Specific Trend:

From1964 to 1966, the total amount of ozone increased from 280 d.u. to 320 d.u. in Antarctica.

Step 6: Drawing Step 6: Drawing ConclusionsConclusions

1.1. Create a ModelCreate a Model• Constructing a representation of an object or Constructing a representation of an object or

process that shows a relationship among the process that shows a relationship among the datadata

• Visual, verbal or mathematicalVisual, verbal or mathematical

2.2. Inferring Inferring • Conclusion made on the basis of the facts or Conclusion made on the basis of the facts or

data gathered during your experimentdata gathered during your experiment3.3. Forming a TheoryForming a Theory

• May be formed after May be formed after many related hypothesis many related hypothesis have been tested and supportedhave been tested and supported by much by much experimental dataexperimental data

• Broad and comprehensive statement that is Broad and comprehensive statement that is thought to be truethought to be true

Step 7: Repeat!Step 7: Repeat!

Make sure the data is Make sure the data is accurate (you can reproduce accurate (you can reproduce

it)it)

Precision: how close you are Precision: how close you are to the actual numberto the actual number

Do you think all steps are used Do you think all steps are used all the time and in the same all the time and in the same order?order?

Think-pair-shareThink-pair-share

Ellen set up three identical ten-gallon Ellen set up three identical ten-gallon aquariums.  The walls and tops were covered aquariums.  The walls and tops were covered with black construction paper to prevent light with black construction paper to prevent light from entering.  Ten feeder guppies were added from entering.  Ten feeder guppies were added to each aquarium as test subjects.  A small to each aquarium as test subjects.  A small corner of each aquarium was left open, and a corner of each aquarium was left open, and a small reading light is placed over it.  Each day, small reading light is placed over it.  Each day, the light is turned on over the aquarium, and the light is turned on over the aquarium, and thirty seconds later, a small amount of food is thirty seconds later, a small amount of food is added to two of the aquariums.  No food is added to two of the aquariums.  No food is added to the third aquarium at this time.  Every added to the third aquarium at this time.  Every five days for twenty days, the number of fish five days for twenty days, the number of fish that come to the light before the food is offered that come to the light before the food is offered is recorded.is recorded.

Ticket out the door – Ticket out the door – identify EXDidentify EXD