Transcript Observation & Inference

WHAT IS THE
NATURE OF
SCIENCE?
THIS IS SCIENCE AND IT IS
BASED ON THESE:
1. The Universe Is Understandable.
2. The Universe Is a Vast Single System In Which the
Basic Rules Are Everywhere the Same.
3. Scientific Ideas Are Subject To Change.
4. Scientific Knowledge Is Durable.
5. Science Cannot Provide Complete Answers to All
Questions.
6. Science only investigates the natural world.
WHAT IS THE NATURE OF
SCIENTIFIC INQUIRY?
• Certain features of science make it
distinctive as a means of
understanding the world/universe
• Those features are especially
characteristic of the work of
professional scientists, but anyone can
use them to think scientifically about
many aspects of everyday life
Science Demands Evidence
• The validity of scientific claims is
settled by referring to observations of
phenomena
• Therefore, scientists concentrate on
getting accurate data
Observation & Inference of the
natural world
It all starts here!
modified Eric Albro from Liz LaRosa www.middleschoolscience.com 2009, The original posted at:
www.science-class.net/PowerPoints/Observation_Inference_8th.ppt
Observations
• Any information collected with the senses.
• Quantitative – measureable or countable
»
»
»
»
3 meters long
4 marbles
50 kilograms
35 degrees Celsius
• Qualitative – describable, not measureable
» red flowers
» smells like fresh baked cookies
» Tastes bitter
• The skill of describing scientific events
Inference
• Conclusions or deductions based on observations.
• The process of drawing a conclusion from given
evidence.
Practice:
• Observations:
• I hear people screaming
• I smell cotton candy, popcorn, and hamburgers
• I see a lot of people
• Inference = ?
Observation
• What is an observation?
– Using your five senses to take note of
and observe your surroundings
– List the five senses
Inference
• An inference is when you make an
assumption or prediction about something
that you observe
• After you make an observation, you
usually make an inference about what is
going on
Let’s practice making inferences!
The next three slides show some fossil
imprints that were found during a
archeological dig. We’re going to record
some observations and then make some
inferences about what may have happened
millions of years ago….
Look at these two sets of
animal tracks.
List 3 OBSERVATIONS
Make an INFERENCE
Now what do you think?
Make 3 OBSERVATIONS
Make an INFERENCE
Now what do you think?
Make 3 OBSERVATIONS
Make an INFERENCE
Activity Page
www.middleschoolscience.com/footprints-isn.pdf
In your science notebook, write your conclusion in the form
of ---------------- look at the sentence starters and left
page information.
THE SCIENTIFIC METHOD
1. Observe and describe a phenomenon or group of
phenomena.
2. Formulate hypotheses to explain the phenomena;
hypotheses often take the form of a proposed causal
mechanism or mathematical relationship.
3. Use the hypotheses to predict the existence or
actions of other phenomena, or to predict
quantitatively the results of new observations.
4. Perform additional data collection or repeat
experimental tests of the predictions by several
independent experimenters using properly performed
techniques or experiments.
THE SCIENTIFIC METHOD
• Observations/Data ➔ Hypotheses ➔ Hypothesis
Testing ➔ Models ➔ Laws ➔ Theories
• At some point in time, each stage must be reported to
the larger scientific community by presentations or
publications.
THE SCIENTIFIC METHOD
• The scientific method does not allow any
hypothesis to be proven true.
• Hypotheses can be disproven, in which case
that hypothesis is rejected as false.
• A hypothesis which withstands a test designed
to falsify it establishes a level of probability that
the hypothesis accurately explains data and
can be used for further predictions, subject to
further tests.
Hypothesis Testing
SCIENTIFIC LAWS AND THEORIES
• A Scientific Theory is an explanation of a set
or system of related observations or events
based upon proven hypotheses and verified
multiple times by detached groups of unbiased
researchers.
• (One scientist cannot create a theory; s/he can only
create hypotheses.)
SCIENTIFIC LAWS AND THEORIES
• As a result of our confidence in the Scientific
method, both a scientific law and a scientific
theory are accepted to be “true” (accurate) by
the scientific community as a whole.
• A scientific law or a scientific theory is used to
make predictions of events or relationships
among data sets.
• Both are used to advance technology.
SCIENTIFIC LAWS AND THEORIES
• The biggest difference between a law and a
theory is that a theory is much more complex
and dynamic.
• A law governs a single action or situation,
whereas a theory explains an entire group of
related phenomena.
SCIENTIFIC LAWS AND THEORIES
• Genuine scientific theories must be falsifiable
by means of additional application of the
scientific method (data collection and
hypothesis testing).
• If one cannot imagine a specific investigation or
experiment, based on predictions from the
theory, leading to results which can further
verify or refute the predictions, then the theory,
as an explanation, is not scientific.
SCIENTIFIC LAWS AND THEORIES
• By the time the scientific community accepts a
Law or Theory, it represents the best
understanding of the explanations for the
elements and behaviors of a given system at
that point in time.
• A Scientific Theory represents our best
understanding of the “truth” about some aspect
of the universe, even though it is not proven as
absolute and is still understood to be subject to
future revision, even to rejection.
THE EXPERIMENTAL METHOD
• The Experimental Method is usually considered
the most scientific of all methods, the “method
of choice.”
• The main problem with all other nonexperimental methods is less control over the
situation and its components.
• The Experimental Method is a means of trying
to overcome this problem.
THE EXPERIMENTAL METHOD
• An experiment is a study of cause and effect.
• It differs from non-experimental methods in that
it involves the deliberate manipulation of one
variable, while trying to keep all other variables
constant.
• Experiments must be properly designed and
include controls.
HYPOTHESIS GENERATION
• The use of logic and the close examination of
evidence are necessary but not usually
sufficient for the advancement of science.
• Scientific concepts do not emerge automatically
from data or from any amount of analysis alone.
• Inventing hypotheses or theories to imagine
how the world works and then figuring out how
they can be put to the test of reality is a
creative thought process.
SCIENCE EXPLAINS AND PREDICTS
• Scientists strive to make sense of observations
of phenomena by constructing explanations for
them that use, or are consistent with, currently
accepted scientific principles.
• Such explanations—theories—may be either
sweeping or restricted, but they must be
logically sound and incorporate a significant
body of scientifically valid observations.
• The credibility of scientific theories often comes
from their ability to show relationships among
phenomena that previously seemed unrelated.
SCIENCE EXPLAINS AND PREDICTS
• The essence of science is validation by
observation.
• It is not enough for scientific theories to fit the
observations that are already known.
• Theories should also fit additional observations
that were not used in formulating the theories in
the first place; that is, theories should have
predictive power.
SCIENTISTS TRY TO
IDENTIFY AND AVOID BIAS
• When faced with a claim that something is true,
scientists respond by asking what evidence
supports it.
• But scientific evidence can be biased in how the
data are interpreted, in the recording or
reporting of the data, or even in the choice of
what data to consider in the first place.
• Scientists' nationality, sex, ethnic origin, age,
political convictions, etc., may incline them to
look for or emphasize one or another kind of
evidence or interpretation.
SCIENCE IS NOT AUTHORITARIAN
• It is appropriate in science, as
elsewhere, to turn to
knowledgeable sources of
information and opinion,
usually people who specialize
in relevant disciplines.
• But esteemed authorities
have been wrong many times
in the history of science.
Aristotle
SCIENCE IS SELF CORRECTING
AND PROGRESSIVE
• In the short run, new ideas that do not mesh
well with mainstream ideas may encounter
vigorous criticism, and scientists investigating
such ideas may have difficulty obtaining support
for their research.
• Challenges to new ideas are the legitimate
business of science in building valid knowledge.
SCIENCE AS A WAY OF KNOWING
1.
2.
3.
4.
5.
The Universe Is Understandable.
The Universe Is a Vast Single System In Which the Basic
Rules Are Everywhere the Same.
Scientific Ideas Are Subject To Change.
Scientific Knowledge Is Durable.
Science Cannot Provide Complete Answers to All Questions.
Scientific ideas are developed by particular ways of
observing, thinking, experimenting, and validating.
Observations/Data ➔ Hypotheses ➔ Hypothesis
Testing ➔ Models ➔ Laws ➔ Theories
WHAT IS THE NATURE OF
SCIENCE?
What is SCIENCE ?
The Process
• A process to answer questions & solve problems
• How we understand the natural world around us
• A process used to investigate what is
happening in the natural world around you
• It provides possible answers to what is
happening in the natural world
We answer scientific questions and
solve problems with 2 types of
research.
What are the two types?
1.Qualitative Research: not what we will use
by itself but will be a part of,
2.Quantitative Research
Qualitative Research
• Based mainly on Observations
• Used when experiments are impossible to
perform
• Involves the following:
– Stating the research objective
– Describing the research design
– Eliminating bias
EXPERIMENTAL RESEARCH
Experimental research includes
investigations that:
•
•
•
•
•
Has variables
Test hypotheses
Have a control or control group
Is a set of planned steps
Tests one variable at a time ( a fair
test)
VARIABLE
A part of an investigation that
can be CHANGED
3 TYPES OF VARIABLES
1.Independent Variable
2.Dependent Variable
3.Controlled Variable
INDEPENDENT VARIABLE
You manipulate it!
• The variable that can be changed
during an experiment
• The variable that the scientists
chooses to change
• The variable that may cause a
change in the dependent variable
INDEPENDENT VARIABLE
You manipulate it!
• Example
DEPENDENT VARIABLE
•The factor that is being measured
in an experiment
•The variable that is measured by
scientists
•The variable that may change
because of the independent variable
DEPENDENT VARIABLE
•Example
CONTROLLED VARIABLE
(CONSTANT)
•Variable that stays the same during
an experiment
•Variable that is controlled by the
scientist
•Variable that is not allowed to change
CONTROLLED VARIABLE
(CONSTANT)
•Example:
What is the difference
between
Science and Technology?
Technology is the application of
science
We will use both:
Science  gaining knowledge
Technology  using knowledge
How do scientists OBSERVE?
How do scientists OBSERVE?
Using the 5 senses:
•Hearing
•Touch
•Smell
•Sight
•Taste
RECORDING DATA
Data Tables
• A way to record results and observations
accurately
• Have a descriptive title
• Divided into columns & rows
• Shows the independent variable
• Provides a place to record the dependent
variable
How do scientists
COMMUNICATE the results of
their work?
How do scientists
COMMUNICATE the results of
their work?
• Reported in scientific journals
• Science journals
• Presentations to other scientists
ANALYZE DATA
• Reduce the data with the best measure of
central tendency (you know, mean
median,mode)
• Graph the data
• Look for patterns and relations
• Look at the shape of the graph
What do scientists do when
they
DRAW CONCLUSIONS?
• Answer the original question
• State whether or not the
hypothesis was supported (it is
never “right” or “wrong”)
• Pose questions for further
research
HYPOTHESIS
• A statement that can be tested by
conducting an experiment
• Prior knowledge, new information,
observations can be used to form a
hypothesis
Why are REPEATED TRIALS
necessary in an experiment?
Why are REPEATED TRIALS
necessary in an experiment?
• To make sure results are valid
• The more trials conducted, the more
likely the results are reliable
• To make sure a “fluke” is not
considered the true result
Why do scientists use
MODELS?
Why do scientists use
MODELS?
To save time and money when
testing ideas that are
• Very large
• Very small
• Dangerous
• Time-consuming
Models in Science
What you will learn:
•Describe various types of models
•Discuss limitations of models
•Vocabulary
Models
Questions and Keywords
Notes
– Scientific Theory and Scientific Law
What is the
difference between
Scientific Theory
and Laws
• A Scientific Law describes a pattern in
nature
• A scientific theory explains a pattern
observed repeatedly in nature
What is a
system
Summary
– Systems in Science
• Structures, cycles, and processes
Questions and Keywords
Notes
• Previously we have learned
What are the kinds
of Science
– Types of Science
• Physical—matter and energy
• Life—Living systems
• Earth—earth systems and systems in space
What is the
Scientific Method
– Scientific Method
• A step by step process that observes,
questions, hypothesizes, experiments,
What is Inferring
analyzes and makes a conclusion
– Infer
• A conclusion based on what you have
Summary
observed in your investigation
Questions and Keywords
Notes
• Lab Safety
Summary
Models in Science
Questions and Keywords
What is a model
How does a
model help
scientists
Summary
Notes
• In Science a model is any representation
of an object or an event used as a tool for
understanding the real world
• Models help scientists see and study complex
things and what cannot be seen, that move too
quickly, or that do not exist anymore
– Example: Mystery Box
Models in Science
Questions and Keywords
What are
different kinds
of Physical
Models?
What does a
computer model
displays?
What do idea
models
communicate?
Summary
Notes
• Types of Models
– Physical Models
• What are other kinds of
models
• …
– Computer Models
• Hurricane Igor
• …
– Idea Models
• Models that describe how
someone thinks about
something in the natural
world
Questions and Keywords
Write a
question
about each
topic
Your
Notes
Turn
• Making Models
– Models Communicate
• List the main ideas, and:
•
Summary
Draw a model of the classroom. Imagine someone who has never seen it.
Questions and Keywords
How do models test
predictions
Your
Notes
Turn
• Models that test predictions
– List the main ideas in the text
–
How do models
save time,
money, and lives
Summary
What is the model used in the Mystery Box Demonstration?
• Models save time, money, and lives
–
List three examples found in the text
Questions and Keywords
Write a
question
about each
topic
Your
Notes
Turn
• Limitations of Models
• List the main ideas in the text
– Models Change—
• List the main ideas in the text
Summary
Source of graphic:
http://bob.nap.edu/html/evolution98/evol6-e.html