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
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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