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The Nature of Science
Preamble
All those involved with science teaching and learning should have
a common, accurate view of the nature of science. Science is
characterized by the systematic gathering of information through
various forms of direct and indirect observations and the testing of
this information by methods including, but not limited to,
experimentation. The principal product of science is knowledge in
the form of naturalistic concepts and the laws and theories related
to those concepts.
Declaration
The National Science Teachers Association endorses the
proposition that science, along with its methods, explanations and
generalizations, must be the sole focus of instruction in science
classes to the exclusion of all non-scientific or pseudoscientific
methods, explanations, generalizations and products.
The following premises are important to understanding the nature
of science.
Scientific knowledge is simultaneously reliable and tentative.
Having confidence in scientific knowledge is reasonable while
realizing that such knowledge may be abandoned or modified in
light of new evidence or reconceptualization of prior evidence and
knowledge.
Although no single universal step-by-step scientific
method captures the complexity of doing science, a number of
shared values and perspectives characterize a scientific approach to
understanding nature. Among these are a demand for naturalistic
explanations supported by empirical evidence that are, at least in
principle, testable against the natural world. Other shared elements
include observations, rational argument, inference, skepticism,
peer review and replicability of work.
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Nature of Science Position Statement - NSTA Position Statements
http://www.nsta.org/about/positions/natureofscience.aspx
Creativity is a vital, yet personal, ingredient in the production of
scientific knowledge.
Science, by definition, is limited to
naturalistic methods and explanations and, as such, is precluded
from using supernatural elements in the production of scientific
knowledge.
A primary goal of science is the formation of theories
and laws, which are terms with very specific meanings.
1.
Laws are generalizations or universal relationships related to
the way that some aspect of the natural world behaves under
certain conditions.
2.
Theories are inferred explanations of some aspect of the
natural world. Theories do not become laws even with
additional evidence; they explain laws. However, not all
scientific laws have accompanying explanatory theories.
3.
Well-established laws and theories must be internally
consistent and compatible with the best available evidence;
be successfully tested against a wide range of applicable
phenomena and evidence;
possess appropriately broad and
demonstrable effectiveness in further research.
Contributions to science can be made and have been made by
people the world over.
The scientific questions asked, the
observations made, and the conclusions in science are to some
extent influenced by the existing state of scientific knowledge, the
social and cultural context of the researcher and the observer's
experiences and expectations.
The history of science reveals both
evolutionary and revolutionary changes. With new evidence and
interpretation, old ideas are replaced or supplemented by newer
ones.
While science and technology do impact each other, basic
scientific research is not directly concerned with practical
outcomes, but rather with gaining an understanding of the natural
world for its own sake.
References
Moore, J. 1993. Science as a Way of Knowing: The Foundation of
Modern Biology. Cambridge, MA: Harvard University Press.
American Association for the Advancement of Science (1993).
Benchmarks for Science Literacy: Project 2061. New York:
Oxford University Press.
National Science Teachers Association (1997). The Teaching of
Evolution—A Position Statement of NSTA. Washington, DC.
National Academy of Sciences (1998). Teaching About Evolution
and the Nature of Science. Washington, DC: National Academy
Press.
McComas, W., Clough, M., & Almazroa, H. (1998). The role and
character of the nature of science in W. F. McComas (Ed.) The
Nature of Science in Science Education: Rationales and Strategies
(pp. 3–39) Boston: Kluwer Academic Publishers.
National Association of Biology Teachers. (1987) Scientific
Integrity—A Position Statement.
—Adopted by the NSTA Board
of Directors
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Notice
Animalcules Lab
Background
When Anton van Leeuwenhoek worked to improve the newly
improved microscope, he viewed various samples. Some such
things he viewed were rainwater, pond water, and dust. In some of
these samples, he observed living things, often small and singlecelled. He called these ‘animalcules’ which means small or tiny
animals. As these animals appeared to have originated from the
water or dust itself, van Leeuwenhoek’s discovery seemed to
support the theory of spontaneous generation.
In this lab, you will make microscope samples of hay-infusion in
which you may observe both biotic and abiotic substances.
Materials
Microscope
Well slide
Cover slip
Hay-infusion
Dropper
Kim wipe
Methods
1. Prepare the microscope.
2. Set out the well slide and cover slip.
3. Use the dropper to obtain water from the bottom of the
hay-infusion.
4. With the slide in front of you, hold the dropper with the
bulb in your hand over the slide. Let the more solid
material drift down to the open nozzle end of the
dropper. DO NOT SHAKE.
5. Drop about 2-3 drops into the center of the well slide or
until the well is full.
6. Use standard procedures for adding the cover slip.
7. View the slide on low power.
a. Make a model of what you see.
b. Remember title and label.
c. Record power.
d. Identify solid material.
e. Identify moving images if possible.
8. View the slide on medium power.
a. Make a model of what you see.
b. Remember title and label.
c. Record power.
d. Identify solid material.
e. Identify moving images if possible.
9. View the slide on high power.
a. Make a model of what you see.
b. Remember title and label.
c. Record power.
d. Identify solid material.
e. Identify moving images if possible.
10.
Clean the droppers, slides, and cover slips.
11.
12.
Return materials.
Clean the lab bench and the drain.
Discussion Questions
1. At what power did living things appear that were
moving? How do you think power may have influenced
what early researchers saw and thought about when
using more primitive microscopes?
2. How does your lab result either support or refute the idea
of spontaneous generation? Give supporting evidence.
Biogenesis or Abiogenesis, THAT is the Questions!
Background:
“A witch, a witch. Burn her!” My favorite movie, Monty Python
and the Holy Grail. During the pre-Enlightenment times, people
questioned why things happened just like today. They, however,
lacked the technology that we have today to help them find better
theories for why things happened. In order to explain phenomena
that they saw, they sometimes blamed bad things on supernatural
beings, such as ‘witches’. Sometimes, they explained what
happened by associating events that seemed to be cause and effect.
Remember sanitation wasn’t the best, there was no refrigeration,
and bacteria were unknown at this time. So it might be
understandable to come up with the following statement: “If
I…leave the rags that I used when butchering a pig in the corner
dirt floor of my hut, Then…several weeks later I see rat babies.”
Under these circumstances and with these observations, I might
conclude that “Rags give birth to rats”. Sounds like a winner to me.
This idea that living things may arise from non-living things is
called ‘Abiogenesis’.
Since the Age of Enlightenment, scientists have tried to be more
rigorous in crafting explanations for phenomena. We try to collect
as much evidence first using experiments that have controls and
specific variables before suggesting a theory for why rats appear in
rags. We now know, under specific circumstances, that only living
things can produce other living things; therefore, only rats can
produce more rats and dirty rags can produce nothing (unless you
consider the odor). This idea that only living things can produce
other living things is called ‘Biogenesis’. When it was first
proposed, it was a big deal. For a very long time in human history,
abiogenesis was the accepted explanation. Remember that the
NOS, ‘nature of science’, is called tentative. This means that
explanations that we make today may be pitched out tomorrow
when based on new knowledge, new evidence, or a new
interpretation of old evidence. When we watched Men in Black
and were told that, “Fifteen hundred years ago, everybody knew
the Earth was the center of the universe, and five hundred years
ago, everybody knew the Earth was flat. Imagine what we’ll know
tomorrow”. So we obviously change our ideas about things based
on evidence.
You will do a short lab using a hay-infusion. This is simply yard
clippings, flower pot dredgings, etc. left to sit in water at room
temperature. The clippings and dredgings are not alive, which
represent the same type of situation that the rags represented. The
rag fibers may have been flax, a plant commonly used to produce
cloth much like cotton fibers are used to make cloth. The clipping
fibers will be the rags in this experiment. I’ve left them sit for a
period of time and you will investigate what they have produced.
Do the Animacules Lab.
Graphic Organizer for Reading to Support Argumentation
for:
Does science really 'prove' anything (Yes or No)? The difference
between what we know because we see physical evidence (law)
and how we explain phenomena (theory) is differentiated.
Name_________________________________
*Number all of your reading sources. Use these numbers in the
Ref # block below.
Directions: As you read a variety of resources, write comments
(your questions or thoughts as you read), supporting evidence,
refuting evidence, and references relative to the topic.
Questions or
Comments
Supporting
Evidence
Refuting Evidence Ref #
Questions or
Comments
Page 2
Supporting
Evidence
Questions or
Page 3
Supporting
Refuting Evidence Ref #
Refuting Evidence Ref #
Comments
Evidence
Page 4
Use the graphic organizer below to summarize and make
inferences from what you read.
Inferences
Summary of
Summary of
Ref #
Supporting Ideas
Refuting Ideas
Page 5
Make a quick graphic organizer of how your ideas relate and
will be used in your argument paper.
Reference Key:
#
1
2
Title
3
4
5
6
7
Writing ideas:
1. Write as if…’You are there’.
2. Interview the participants on different sides of the
argument.
3. Include quotes from both sides.
4. Use specific statistics if possible.
5. Stay focused and answer the question.
6. Use expert opinion.
7. Point out inconsistencies.
Nature of Science—Word Bank
Wronger Than Wrong
1. Genre – A group of things (books) based on like
characteristics or traits.
2. Invectives – Insult or abuse.
3. Canonical – An accepted principle or rule
4. Ne – Originally, or formerly called…
5. Proverb – A saying with a moral or ethical point to it.
6. String Theory – Theory that may describe gravity and
weak electromagnetic forces, provides for up to 11
dimensions (such as time, length, width, height).
7. Eminence – Position of prominence, superiority.
8. Axiom – An statement accepted as true.
9. Attenuate – Reduced, cut off.
10.
Inextricable – Tangled, incapable of being freed.
11.
Predilection – Preference for something.
12.
Capitalist – Production of goods and services is
primarily privately owned, operated in a free-market.
13.
Hegemony – Influence of authority over others.
14.
Egregious- Flagrant, conspicuous.
15.
Elucidate – Explain in plain terms.
16.
Law – Generalization that describes a phenomenon.
17.
Theory – A statement that explains a phenomenon.
What Is Science
1.
2.
3.
4.
Iterate – To say or do again and again.
Dogma – Something held as an established opinion.
Mechanism – How a thing happens.
Scientific Metaphysics – An idea that originates in
scientific knowledge, but has not been subjected to the
full scientific testing and review process to make it a
theory.
5. Pejorative – Something written or spoken in order to put
forth a negative opinion.
Falsifiability- Testable. A quality or characteristic of a
scientific hypothesis or theory. Falsifiability is considered a
positive (and often essential) quality of a hypothesis because it
means that the hypothesis is testable by empirical experiment
and thus conforms to the standards of scientific method. That
something is ‘falsifiable’ does not mean it is false, rather it
means that if it is false, then observation or experiment will at
some point demonstrate its falsehood. For example: the
assertion that all ‘all swans are white’ is falsifiable, because it is
logically possible that a swan can be found that is not white. Not
all statements that are falsifiable in principle are falsifiable in
practice. For example, ‘It will be raining here in one million
years’ is theoretically falsifiable, but not practically so.
Spontaneous Generation
Spontaneous Generation



The idea that organisms originate directly from nonliving
matter.
"life from nonlife"
abiogenesis - (a-not bio-life genesis-origin)
The Scientist below ran experiments to prove or disprove the
theory of spontaneous generation. Review their experiments and
attempt to answer the questions on the bottom of this page.
Francesco Redi - One of the first to disprove spontaneous
generation. An Italian doctor who proved maggots came from flies.
(Italian 1668)
Lazzaro Spallanzani - One of the first to disprove spontaneous
generation. An Italian scientist who proved microorganisms could
be killed by boiling. (Italian 1767)
Louis Pasteur - One of the first to disprove spontaneous
generation. A French scientist who proved that micro organisms
was carried by dust not air. (French 1864)
Questions: If you can answer the following questions you indicate
a good understanding of this material.
Why did early people believe in spontaneous generation?
In Redi's experiment why did the flies lay their eggs on the
netting?
What important process in canning did Spallanzani teach us?
How has the information from these scientists been used to protect
our food from going bad? (application of information-technology)
What process was named after Pasteur?
Approximately how many years apart were the experiments of
these three famous scientists?
What does the phrase "Life From Life" Mean?
Is the theory of spontaneous generation considered to be correct or
incorrect? Why?
If you accept the idea that spontaneous is incorrect - explain how
life started on the earth? Geologists have evidence that there was a
very long period of time when the earth had no living organisms.
If you would like to comment or ask questions, contact:
Webmaster
Copyright ©, 1998 Tim Lynch
Redi's Experiment
Francesco Redi - One of the first to disprove spontaneous
generation. An Italian doctor who proved maggots came from flies.
(Italian 1668)
Spontaneous Generation



The idea that organisms originate directly from nonliving
matter.
"life from nonlife"
abiogenisis - (a-not bio-life genesis-origin)
Redi's Problem
Where do maggots
come from?
Hypothesis: Maggots
come from flies.
Redi put meat into
three separate jars.
Jar 1 was left open
Jar 2 was covered
with netting
Jar 3 was sealed from
the outside
Redi's Experiment
Step 1
Jar-1
Left open
Maggots developed
Flies were observed
laying eggs on the
meat in the open jar
Redi's Experiment
Step 2
Jar-2
Covered with netting
Maggots appeared on
the netting
Flies were observed
laying eggs on the
netting
Redi's Experiment
Step 3
Jar-3
Sealed
No maggots
developed
Redi's Experiment
Results
What did Redi's
experiment show?
Was his hypothesis
correct or incorrect?
Return to Spontaneous Generation Page
If you would like to comment or ask questions, contact:
Webmaster
Copyright ©, 1998 Tim Lynch
Lazzaro Spallanzani's Experiment
Lazzaro Spallanzani - One of the first to disprove spontaneous
generation. An Italian scientist who proved microorganisms could
be killed by boiling. (Italian 1767)
Spontaneous Generation



The idea that organisms originate directly from nonliving
matter.
"life from nonlife"
abiogenisis - (a-not bio-life genesis-origin)
Spallanzani's Problem
What causes microbes to form in decaying
broth?
Hypothesis: Microbes come from the air.
Boiling will kill microorganisms.
Spallanzani put broth into four flasks
Flask 1 was left open
Flask 2 was sealed
Flask 3 was boiled and then left open
Flask 4 was boiled and then sealed
Spallanzani's Experiment Step 1
Flask-1
Left Open
Turned cloudy
Microbes were found
Spallanzani's Experiment Step 2
Flask-2
Sealed
Turned cloudy
Microbes were found
Spallanzani's Experiment Step 3
Flask-3
Boiled and left open
Turned cloudy
Microbes were found
Spallanzani's Experiment Step 4
Flask-4
Boiled and sealed
Did not turn cloudy
Microbes not found
Spallanzani's Experiment Results
What did Spallanzani's experiment show?
Was his hypothesis correct or incorrect?
Return to Spontaneous Generation Page
If you would like to comment or ask questions, contact:
Webmaster
Copyright ©, 1998 Tim Lynch
Louis Pasteur 's Experiment
Louis Pasteur - One of the first to disprove spontaneous
generation. A French scientist who proved that micro organisms
was carried by dust not air. (French 1864)
Spontaneous Generation



The idea that organisms originate directly from nonliving
matter.
"life from nonlife"
abiogenisis - (a-not bio-life genesis-origin)
Pasteur's Problem
Where do the microbes come from
to cause broth to decay.
Hypothesis: Microbes come from
cells of organisms on dust
particles in the air; not the air
itself.
Pasteur put broth into several
special S-shaped flasks
Each flask was boiled and placed
at various locations
Pasteur's Experiment Step 1
S-shaped Flask
Filled with broth
The special shaped was intended
to trap any dust particles coming
in.
Pasteur's Experiment Step 2
Flasks boiled
Flasks boiled
Micropes Killed
Pasteur's Experiment Step 3
Flask Left Out
Flask left at various locations
Did not turn cloudy
Microbes not found
Pasteur's Experiment Step 3
Flask Left Out
Notice the dust that collected in
the neck of the flask
Pasteur's Experiment Results
What did Pasteur's experiment
show?
Was his hypothesis correct or
incorrect?
Return to Spontaneous Generation Page
If you would like to comment or ask questions, contact:
Webmaster
Copyright ©, 1998 Tim Lynch
http://www.biology-online.org/dictionary/Spontaneous_generation
Spontaneous generation
Definition
The previously popular notion that living organisms arise or
develop from nonliving matter.
Supplement
The theory of spontaneous generation held that complex, living
organisms may be produced from nonliving matter. It was a
popular belief that mice occur spontaneously from stored grain, or
maggots spontaneously appear in meat.
Related phrases: theory of spontaneous generation.
Synonym: autogenesis, autogeny, abiogenesis.
Compare: biogenesis.