Nature of Science/Scientific

Method Unit 1, Notes

What Is Science?

The goal of science is to:– investigate and understand the natural world

– explain events in the natural world

– use those explanations to make useful predictions

In short, science is an organized way of using evidence to learn about the natural world.

Questions to ConsiderQuestions to Consider

How can we determine if something is fact or opinion?

How can we determine an answer to a problem?

ANSWER…

THE SCIENTIFIC METHOD!

Step 1Step 1Ask a QuestionAsk a Question

- - define the problemdefine the problem

- make sure only one problem is being studied- make sure only one problem is being studied

based on your observationbased on your observation

- observations are made by using your 5 - observations are made by using your 5

sensessenses

touchtouch tastetaste

smellsmell sightsight

hearinghearing

Step 2Step 2

Research the problemResearch the problem

– use all available resources to collect data on use all available resources to collect data on the subject being covered.the subject being covered.

– Ex: library, internet, books, magazines, Ex: library, internet, books, magazines, interviews, etc.interviews, etc.

Step 3Step 3

Develop a Hypothesis Develop a Hypothesis

-- educated guess-- educated guess

– make it a short and definitive statementmake it a short and definitive statement

– it should be in “If….” “Then….” formatit should be in “If….” “Then….” format

– the “if part” is the hypothesisthe “if part” is the hypothesis

– the “then part” is what you think the results the “then part” is what you think the results

will be at the end of the controlled will be at the end of the controlled

experiment.experiment.

– a hypothesis can be changed.a hypothesis can be changed.

Step 4Step 4Develop a Controlled ExperimentDevelop a Controlled Experiment

– contains only one experimental variable, known as the manipulated variable. I.E. the thing being tested

– Everything else in the experiment or all other variables must be the same.

– called constant variables– keeping these the same allows the scientists to show that it was the experimental variable that caused the results.

Variables in a Variables in a Controlled ExperimentControlled Experiment

Manipulated Variable: the variable you are testing; also called independent variable

Control Set-UpControl Set-Up: what you compare to, no manipulated variable used

Responding Variable: variable you measure; changes in response to the manipulated variable

Constant Variables: consistent between all trials

Step 5Step 5

Record and analyze the dataRecord and analyze the data– the data may or may not support the the data may or may not support the

hypothesis. hypothesis. – if the data proves the hypothesisif the data proves the hypothesis wrongwrong, change , change

the hypothesis, the hypothesis, notnot the data. the data. – if the data if the data supportssupports the hypothesis, additional the hypothesis, additional

experimentation must then take place to build experimentation must then take place to build

documentation to support the hypothesisdocumentation to support the hypothesis

Types of DataTypes of Data

Quantitative Data

- expressed as numbers

- obtained by counting or measuring

- Ex: 50 ml, 800 km, 45 sec

Qualitative Data

- descriptive

- Ex: clear, spherical, smooth

Step 6

Draw A Conclusion

- use the evidence to support

or refute the hypothesis

- a proven hypothesis must

stand up to additional testing

- other scientists repeat each

others investigations

Step 7: Peer ReviewStep 7: Peer Review

Scientist will share findings and Scientist will share findings and collaborate with other scientists. collaborate with other scientists.

Other scientists MUST be able to replicate Other scientists MUST be able to replicate the experiment and get the same results. the experiment and get the same results.

Example:

Ask a question, identify problem: Is Raid the best insecticide on the market?

Research: Look up information on insecticides , what are the active ingredients, how many insects will it kill, how much does it cost, etc..

Hypothesis: Raid is the best insecticide on the market. It will kill insects 30% faster than other insecticides.

ExperimentExperiment: : – Spray 5 plates with equal amounts of 5 Spray 5 plates with equal amounts of 5

different insecticides. different insecticides. – Cover each one with the same type and size Cover each one with the same type and size

of glass. of glass. – Add equal numbers of the same species of Add equal numbers of the same species of

insect to each plate. Place the plates side by insect to each plate. Place the plates side by side. side.

– Time the resultsTime the results– Observe and record the number of Observe and record the number of insects that die.insects that die.

Collect data and analyzeCollect data and analyze: This is done by writing : This is done by writing down the # of insects that died or how fast they died down the # of insects that died or how fast they died and then organizing that information into a graph so and then organizing that information into a graph so you can better see what happened in the experiment.you can better see what happened in the experiment.

ConclusionConclusion: This is done after the data from the : This is done after the data from the experiment has been collected and analyzed. In this experiment has been collected and analyzed. In this step you will find out if you were correct and Raid was step you will find out if you were correct and Raid was the best or if your hypothesis was rejected!the best or if your hypothesis was rejected!

Different Types of Different Types of Scientific Scientific

InvestigationsInvestigations

Descriptive, Comparative and Descriptive, Comparative and Experimental InvestigationsExperimental Investigations

Comparative InvestigationsComparative Investigations

involve collecting data on different involve collecting data on different organisms/objects/ features/events, or collecting organisms/objects/ features/events, or collecting data under different conditions (e.g., time of year, data under different conditions (e.g., time of year, air temperature, location) to make a comparison.air temperature, location) to make a comparison.

The hypothesis identifies one independent The hypothesis identifies one independent (manipulated) variable and one dependent (manipulated) variable and one dependent (responding) variable. A fair test can be designed to (responding) variable. A fair test can be designed to measure variables so that the relationship between measure variables so that the relationship between them is determined. them is determined.

involve designing a “fair test” similar to a involve designing a “fair test” similar to a comparative investigation, but a control is comparative investigation, but a control is identified. The variables are measured in an identified. The variables are measured in an effort to gather evidence to support or not effort to gather evidence to support or not support a causal relationship. This is often called support a causal relationship. This is often called a controlled experiment. a controlled experiment.

A fair test is conducted by making sure that only A fair test is conducted by making sure that only one factor (variable) is changed at a time, while one factor (variable) is changed at a time, while keeping all other conditions the same. keeping all other conditions the same.

Experimental investigationsExperimental investigations

Descriptive InvestigationsDescriptive Investigations

Descriptive investigations involve collecting qualitative and/or quantitative data to draw conclusions about a natural or man-made system (e.g., rock formation, animal behavior, cloud, bicycle, electrical circuit).

A descriptive investigation includes a question, A descriptive investigation includes a question, but no hypothesis. Observations are recorded, but no hypothesis. Observations are recorded, but no comparisons are made and no variables but no comparisons are made and no variables are manipulated are manipulated