04/21/23 Nature of Science

What does science mean to you

???

To scientists…

It is a way of learning about the natural world…

using a process designed to reduce the chance of

being misled.

What Science Is Not• Science is not just the accumulation of

facts.• Science does not “prove” something to

be true.• Science is not intended to answer

“right or wrong” questions…that is for philosophy, ethics & religion.

• Science does not deal with supernatural or magical.

04/21/23 Nature of Science

• Laws - describes what nature does under certain conditions, and will predict what will happen as long as those conditions are met. (http://science.kennesaw.edu/~rmatson/3380theory.html)

Theories & Laws

LAW THEORY

• Theory - comprehensive explanation of a variety of observations of an important feature of nature (not a “guess”)

• Supported by many facts & experimental evidence gathered over time

• Allows scientists to make predictions about as yet unobserved phenomena.

• Objective - all data considered

• Rational - clear, logical connections between data while forming theory

• Highest level of reliability in science. “Extraordinary claims require extraordinary evidence.”

Scientific Theories Are:

04/21/23 Nature of Science

Debate and revision of ideas in science is a natural process. Debate is NOT

evidence that a theory isis fatally flawed.

The Scientific Method

1. Observation

6. Analyze Results

5. Controlled Test

4. Form if-then Hypothesis

3. Background Research (books, experts)

2. Question

7. Tentative Conclusions

8. Peer Review (communicate results)

Setting Up a Controlled Experiment

Control Group

The group of ________ items in an experiment used for __________ the experimental group with; generally the more common, _________, or familiar item.

test

comparing

standard

Experimental Group

The group(s) of _____ items where _____ change (called the ______ variable) has been made.

test

only one

experimental

Variable Parameters: Independent Variable: The factor ___________________ by the scientist; placed on the ______ when graphing.

Dependent Variable: The factor that is ________ upon the variable determined by the scientist; what is _________; placed on the ______ when graphing.

manipulated or changedX - axis

dependentmeasured

Y - axis

Controlled Parameters

Factors that are kept the _____ in both the control and experimental groups.

Not controlling these well can be a source of error in the experiment.

same

If – Then Deductive Hypothesis

Where do they go? Fill In:

*control group *what you measure *experimental group*independent variable*dependent variable

If (experimental group, independent variable),

then (what you measure, dependent variable)

compared to (control group).

If

Then

IndependentVariable

Dependent Variable

Positive Correlation

IndependentVariable

Dependent Variable

Negative Correlation

IndependentVariable

Dependent Variable

No Correlation

Next is an example of using the process of science to answer a question you’ve probably had to answer many times when you flick on a light switch and the light doesn’t turn on.

– “Why didn’t the light turn on?”

Everyone uses science.Scientists just use it consciously

and follow some basic rules.

1. OBSERVATION

The light doesn’t turn on

2. QUESTION

Why didn’t the light turn on?

3. LITERATURE REVIEW

Find out what lights require to function and what can cause them

not to function.

4. MULTIPLE HYPOTHESES

What are all the possible answers (hypotheses) to

the question?

H1: A fuse was blown

H2: The lamp is unplugged

H3: The light bulb is burned out

You need to think of many hypotheses to avoid jumping to a conclusion

5. DEDUCTIONS (PREDICTIONS)For each hypothesis, determine what

evidence (data) would be required to refute or support the hypothesis?

1) If the fuse is blown, then no appliances will work

2) If the lamp is unplugged, then the light will work when the lamp is plugged in

3) If the light bulb is burned out, then it will rattle when shaken

Examples:

6. TESTS/ EXPERIMENTS

Conduct tests to collect actual data

Examples:

1)Turn on the other appliances

2)Make sure lamp is plugged in

3) Shake the light bulb & listen for rattle

Analyze Results

• Find mean, median, mode• Calculate the percent difference between the control group and the experimental group

Ex: “The experimental group was 25% more likely to light up than the control group.

7. TENTATIVE CONCLUSIONS

Compare actual results to predicted results for each hypothesis and record which hypotheses were supported and which were refuted in a report for publication.

When actual results are the same as the expected results for an hypothesis, the hypothesis is supported; when actual results differ from the expected results, then the hypothesis is refuted.

7. TENTATIVE CONCLUSIONS

Which hypotheses were supported/refuted by the actual data?

H1 refuted -Other appliances worked

H2 refuted -Lamp was plugged in

H3 supported-Bulb rattled when shaken

Tentative Conclusion: Light bulb was burned out

Test H3 again by trying a functioning

light bulb in the lamp!

8. PEER REVIEW

Write up report (introduction, methods, results, discussion) & submit to a scientific journal that is peer-reviewed, meaning that your methods, data,

tentative conclusions will be scrutinized by scientists whose reputation is at stake if they

allow your report to be published.

Information is not scientific until it has been published in a peer-reviewed, scientific journal.

The Process of Science: Review of Example

1. Observation: Ex. The light doesn’t turn on

2. Question: Ex. Why didn’t the light turn on?

3. Literature Review: Ex. Read about light failures

4. Multiple Hypotheses: Ex. Light bulb burned out, etc.

5. Deductions to get Predicted Results: if the bulb is burned out and I shake the bulb, then I predict it should rattle.

6. Conduct Actual Experiments to get Actual Results: I shook the bulb and it rattled.

7. Tentative Conclusions: because the bulb rattled when shaken as predicted by the burned out bulb hypothesis, I therefore tentatively conclude that a likely explanation for the light not turning on is that the bulb is burned out.

8. Peer Review: submit report to peer-reviewed scientific journal

Science Rules of Thumb1. Maximize Sample Size:

The larger the sample size the more accurate the estimate.

2. Representative Sample:

The sample must represent the variation in the population. E.g., Use random or systematic sampling to avoid biasing the data.

E.g., you don’t want your sample to include only men if you are studying the effect of a medicine on people.

Science Rules of Thumb3. Use Controlled Experiment for Causal

Questions

Use to answer questions concerning what caused

something to happen. Two groups (control & experimental) are treated identically except for the one factor being tested

In conclusion, science is:

• a process for learning about the natural world, using a method designed to reduce the chance of being misled.

• what most people use unconsciously to solve everyday problems

Scientists just consciously apply the process to answer

questions about the world & communicate the results through peer reviewed journals