Scientific InvestigationScientific Investigation

What is Science?What is Science?

Something we DO to help us Something we DO to help us understand the world around usunderstand the world around us

Evidence-based blend of logic & Evidence-based blend of logic & innovationinnovation

Durable BUT can still change!Durable BUT can still change!

Steps of a Scientific InvestigationSteps of a Scientific Investigation1.1. Ask a question/identify a problemAsk a question/identify a problem

2.2. Observations & inferencesObservations & inferences

3.3. Form a hypothesis & make Form a hypothesis & make predictionspredictions

4.4. Design & conduct an experimentDesign & conduct an experiment

5.5. Collect & analyze resultsCollect & analyze results

6.6. State your conclusionState your conclusion

7.7. Communicate your resultsCommunicate your results

1. Ask a Question/ ID a problem1. Ask a Question/ ID a problemNaturally connected to observationsNaturally connected to observations

Mendel – Why are there so many Mendel – Why are there so many purple flowers on pea plants?purple flowers on pea plants?

Why don’t all smokers get lung Why don’t all smokers get lung cancer?cancer?

Will studying more at night actually Will studying more at night actually help my test grades?help my test grades?

Are energy drinks bad for you?Are energy drinks bad for you?

2. Observations & inferences2. Observations & inferences

Inference – Conclusion based on Inference – Conclusion based on your observationsyour observations

3. Formulate a Hypothesis & Make 3. Formulate a Hypothesis & Make a Predictiona Prediction

HypothesisHypothesis Explanation that might be trueExplanation that might be true Can be testedCan be tested Based on what is already knownBased on what is already known

PredictionPrediction Expected outcome of test, assuming Expected outcome of test, assuming

hypothesis is correcthypothesis is correct

UNDERSTANDING UNDERSTANDING CHECKCHECK

4. Design & conduct an 4. Design & conduct an experimentexperiment

Experiment – planned procedure to Experiment – planned procedure to test a hypothesistest a hypothesis

Controlled experimentControlled experiment Experimental group(s) vs. Control Experimental group(s) vs. Control

groupgroup Groups are identical except for ONE Groups are identical except for ONE

variablevariable

4. Design & conduct an 4. Design & conduct an experimentexperiment

Independent variable – factor that is Independent variable – factor that is changed in the experimental groupschanged in the experimental groupsWhat you What you CHANGECHANGE between between

groupsgroupsDependent variable – what you Dependent variable – what you

MEASUREMEASURE

An example…An example…Hypothesis – Acidic water harms Hypothesis – Acidic water harms

developing salamander embryosdeveloping salamander embryosPrediction – Less salamanders will Prediction – Less salamanders will

hatch from eggs in acidic water.hatch from eggs in acidic water.Experiment – Compare Experiment – Compare

salamanders hatched from eggs in salamanders hatched from eggs in acidic water to those in neutral acidic water to those in neutral water.water.

An example…An example…

Independent VariableIndependent VariableAmount of acid in the water Amount of acid in the water

(High acidity vs. neutral water)(High acidity vs. neutral water)Dependent VariableDependent Variable

# of salamanders hatched from # of salamanders hatched from eggseggs

UNDERSTANDING UNDERSTANDING CHECKCHECK

CONDITION AMOUNT OF

GROWTH

Without fertilizer 3 cm

Fertilizer 1 8.3 cm

Fertilizer 2 5.1 cm

5. Collect & analyze results5. Collect & analyze results

Create a chart and/or graph.Create a chart and/or graph.

CONDITION AMOUNT OF GROWTH

Without fertilizer 3 cm

Fertilizer 1 8.3 cm

Fertilizer 2 5.1 cm

6. State your conclusion6. State your conclusion

Analyze the data.Analyze the data. Which fertilizer leads to the most growth?Which fertilizer leads to the most growth?

CONDITION AMOUNT OF GROWTH

Without fertilizer 3 cm

Fertilizer 1 8.3 cm

Fertilizer 2 5.1 cm

6. State your conclusion6. State your conclusion

What does this graph tell us?What does this graph tell us?

6. State your conclusion6. State your conclusionWhat’s the most effective flea What’s the most effective flea

shampoo?shampoo?

BRAND X BRAND Y BRAND Z

# of Dogs With Fleas

BEFORE AFTER BEFORE AFTER BEFORE AFTER

25 2 25 12 25 5

7. Communicate your results7. Communicate your results Identify sources of error.Identify sources of error.

Which data point is probably invalid?Which data point is probably invalid?

Scientific ExplanationsScientific ExplanationsConsider the source of the info.Consider the source of the info.

Journal vs. newspaperJournal vs. newspaper Importance of collaborationImportance of collaboration

Working togetherWorking together Peer review & objectivityPeer review & objectivity Must evaluate the work of others to Must evaluate the work of others to

ensure VALIDITYensure VALIDITY

Validity (Is it valid?)Validity (Is it valid?)

Is it accurate? Is it accurate? Is it reliable?Is it reliable?Does it answer the question it’s Does it answer the question it’s

supposed to answer?supposed to answer?

Scientific ExplanationsScientific Explanations

Scientific theoriesScientific theories Accepted because tested & confirmed Accepted because tested & confirmed

many times by many peoplemany times by many people BUT no absolute certaintyBUT no absolute certainty Example – Earth is flat, etc.Example – Earth is flat, etc.

Laws – generally accepted to be Laws – generally accepted to be true and universal (gravity)true and universal (gravity)