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The Scientific Method The Scientific Method

The Scientific Method - PowerPoint Presentation

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The Scientific Method - PPT Presentation

Main Idea The goals and processes used in scientific inquiry are the same for all branches of science Goals and Processes of Science The goal of science is to understand and explain events in nature ID: 739216

scientific hypothesis variable data hypothesis scientific data variable variables independent experiments relationship testable controlled method review subjects thalidomide predictive experimental group amount

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Slide1

The Scientific Method

Main Idea: The goals and processes used in scientific inquiry are the same for all branches of scienceSlide2

Goals and Processes of ScienceThe

goal of science is to understand and explain events in nature and use those explanations to make useful predictions.Scientific inquiry is the process used to understand nature based on

evidence

gained through

observation

and

experimentation

. Slide3

The Scientific Method

Most scientific inquiry is carried out using the Scientific Method.The Scientific Method is an organized

and

logical

process of seeking answers to scientific questions

.Slide4

Elements of the Scientific Method

Choose an investigative focusGather information on the topic to be studiedForm a testable hypothesisTest the hypothesisCollect and Record Data

Analyze and Interpret Data

Draw Conclusions

Replicate the Tests

Publish Findings for Peer ReviewSlide5

1.Choose

an investigative focus

What sparks scientific curiosity?

Real life problems

(ex. Ebola outbreak)

Scientific literature or discussion

Observations

*

Direct

see the even

t occur *Indirect – see effects of the eventSlide6

Types of ObservationsDirect – see the event

Indirect – see effects of eventSlide7

2. Gather information

*

Review scientific literature

*

Communicate with others

 Slide8

3. Form a

testable hypothesisHypothesis – a possible

explanation

for

a natural phenomena (

event or observation

)Suggests a

cause and effect

relationship

between variables

MUST be TESTABLE through observation or experimentationForms basis for predictions – expectation about what will happen in the future if the hypothesized relationship exists.Slide9

3 Questions to ask yourself when Writing Hypothesis

1. Does the hypothesis suggest a relationship between variables ? ( Relationship of 2 variables)

2. Can a

test

be done to determine the relationship

between the variables? (Testable) 3. Can it predict future events? (Predictive)Slide10

Check your understanding-Is this a Hypothesis?

If skin cancer is related to ultraviolet light, then people who regularly use tanning booths will have a greater chance of getting skin cancer than those who don’t. Relationship between variables?Testable?Predictive?Slide11

Check your understanding-Is this a Hypothesis?

If I play the lottery, then I will get richRelationship?Testable?Predictive?Slide12

Check your understanding-Is this a Hypothesis?

If plants need the nitrogen to grow, then plants given fertilizer containing nitrogen will grow larger than plants that do not receive the fertilizer.Relationship?Testable?

Predictive?Slide13

Check your understanding-Is this a Hypothesis?

If gum has a high sugar content, then chewing the gum will give me many cavities.Relationship?Testable?Predictive?Slide14

!Careful!

Just because “If…then” is in the statement doesn’t necessarily mean it’s a hypothesis.Just because “If…then” is NOT in the statement doesn’t mean it isn’t a hypothesisSlide15

4. Test the Hypothesis

Methods include:

*Questioning –

Surveys

,

interviews

(forensic, medicine, psychology)

*

Field

Observations – used to study wildlife and human behavior *Controlled experiments

Primatologist Dr. Jane Goodall Slide16

Controlled Experiments

Used to determine the effects of changing one variable while all other variables are held constantVariable – a measurable factor that can vary in amount

Ex: Amount of Temp,

light, water,

medication, time Nonexamples: There are 3 types of variables used in experiments:

1. Independent

2. Dependent

3. Constant Slide17

Variables in Controlled experiments

1. Independent variable – the factor that is purposely varied to see if it has any effect on another variable. Also called the “Manipulated Variable”Only

one

should be used in an experiment.

Plotted on

X

axisEx. Amount of Fertilizer Slide18

Variables in Controlled Experiments

2. Dependent variable – the factor that is monitored to see if/how it “responds” to changing

the

independent variable

Also known as the “

responding

variable”.It may or may not be affected by the independent variable. Plotted on the Y axis

Ex. Number of

tomatos

per plantSlide19

Independent variable – X axisDependent variable –

Y axisSlide20

Variables in Controlled Experiments

It is important to identify other factors that could affect the dependent variable.These must be kept “constant” (unchanging) so that they don’t interfere with the action of the independent variable. If these aren’t controlled, it will be impossible to determine which factor was responsible for any changes observed. Constants – factors that are included but NOT varied in an experiment. These factors are kept “constant” in both setups.

Ex. Amount of water, Amount of sunlightSlide21

Controlled experiments must have 2 groups of subjects

Experimental group – this group of subjects does receive the independent variable2.

Control

group – this group of subjects

does not

receive the

independent variable.This group is used as the basis for comparisonBoth groups include all the

constant

variablesSlide22

Let’s Review that Again….

Subjects in the two setups should be treated exactly the same EXCEPT the subjects in the experimental set up are the only ones that receive the independent variable

.

Only

one

independent variable should be tested at a time.

Include the

largest

number of subjects as possible. Slide23

5. Collect and Record Data

Two categories of data (collected information):

1.

Qualitative

Descriptive

i

nformation based

on observations

made with the senses ( sight, sound, smell, touch) Ex. The whale’s skin is gray and smooth.

Subjective

–depends on person’s viewpoint

 Slide24

2.

Quantitative

Measurable information

that

is written as

a

number value

. Ex. The whale’s mass is 300kg. Objective – does not depend on person’s

viewpoint/ less likelihood of bias

 Slide25

6. Analyze and Interpret Data

Data is

organized

and

statistically analyzed

so that conclusions can be made.

M

ethods

of organizing

recorded data in order to look for patterns:

*Charts, *Graphs, *Tables,

Sources of

error

are identified

 Slide26

7.

Draw Conclusions

Conclusions

are

based on a

comparison

of

the experimental

data

with the original

hypothesis

Data supports hypothesis - Accept hypothesis Data does not support hypothesis- Reject

hypothesis

or Revise

 Slide27

A hypothesis can

NEVER BE PROVED no matter how much data supports it.

Why can they NOT BE PROVEN Ms. Soraparu???

Because we cannot completely know, or control, all variables that may affect the experimental outcome

PROVESlide28

“P” is a Dirty Word in Science

PROVE

Slide29

8. Replicate the Test

Experiments are repeated many times using the same procedure (protocol) to ensure the results are valid and reliable

and not due to chance

Valid

– how well did the test measure what it was designed to measure – was the experiment well designed?

Reliable

-

Other

researchers must be able to perform exactly the

same 

experiment, under the same conditions and get the same resultsSlide30

9. Publish Findings for Peer Review

Peer Review

– Experimental methods and results are published in scientific journals so that they may be critiqued and retested by other scientistsSlide31

Questions that reviewers ask:

“What controls were used?”

“Was the sample size large enough?”

“How many trials were carried out?”

“Did experimenter

bias

affect results?” Slide32

The Story of Thalidomide explains the importance of retesting and peer reviewSlide33

Thalidomide

Drug developed in 1950’s Germany to treat:*Morning Sickness in pregnancy*Myeloma*Forms of leprosySlide34

1962 photo of a baby born to a mother who had taken thalidomide while pregnant. The baby has an extra appendage connected to the foot and a malformation of the right arm.Slide35

1962:

FDA pharmacologist Dr. Frances Kelsey receives an award from President Kennedy for blocking sale of thalidomide in the United States.Slide36

Children of ThalidomideSlide37

Billy Joel’s “We Didn’t Start the Fire” Slide38

All scientists include all these steps of the scientific method into their research but not necessarily in the

same order

.

Data Support Hypothesis

Data DO NOT

Support Hypothesis