Transcript 1.2 Scientific Method - Hudson City School District

1.2 Scientific Method
Initial Observation
• Use your senses to
observe
– See, hear, touch, taste,
smell, etc.
• Can also use tools to
measure
– Temperature, length,
volume, etc.
State the Question
• “What is
the effect
of…”
Hypothesis
• “If…then…” If producing oxygen
bubbles in photosynthesis is
related to light color, then green
light will increase photosynthesis
oxygen bubbles to form.
Writing a Hypothesis
• Hypothesis – educated guess
•
- the general statement
• Write in If … and then…format
• DO WORKSHEET
Experiment
A. Manipulated Variable = Independent
Variable -what you change
goes on the X-axis of the graph
B. Responding Variable =
Dependent Variable -what changes as a
result of what you did – goes on the Y-axis
of the graph
Experiment
• Constants-all the things in the
experiment that stay the same
• In the yeast lab:
same size test tubes
same size rubber tubing
same yeast type
same amount of sugar
Your book called them “controlled variables.”
What constants could there be in this
experiment?
Experiment
• Control – the part of the
experiment that does not have the
independent variable in it
• Use for reference, comparison
• Often the normal condition
Run the tests
Record the data
graphs
charts
video
write observations
measurements
Conclusion
• Agree or disagree
with the hypothesis
• The green light did
not produce the
most oxygen
bubbles.
Remember
NO food or
drink in the
lab
Independent Variable?
Dependent Variable?
How About Maggots?
• Maggot Medicine - MSN Video
Designing an Experiment
1668 refuted
"spontaneous generation"
– life could come from nonlife OR a theory also known
as Aristotelian abiogenesis
(maggots came from rotting
meat, flooded Nile gave rise
to frogs, mice came from
moldy grain)
A Controlled Experiment
• Only one tested variable at a time
• Manipulated Variable (Independent
Variable) – one you change
• Responding Variable – (Dependent
Variable)- one that changes as a result
OBSERVATION
• Flies land on meat that is left uncovered.
Later, maggots appear on the meat.
HYPOTHESIS
• Flies produce maggots.
Redi’s Experiment
• CONSTANTS: all the things kept the same
in an experiment
Size of jars
Type of meat
Location
Temperature
Time
Redi’s Experiment
• CONSTANTS: all the things kept the same
in an experiment
Size of jars
Type of meat
Location
Temperature
Time
Redi’s Experiment
• Independent Variable
Type of covering:
Gauze covering to
keep flies away
from the meat or
solid cover
Redi’s Experiment
Maggots on
netting
Open jar-maggots
on meat
Sealed-no maggots
Conclusion
• Maggots form only when
flies come in contact with
meat.
Repeat the Experiments
Other scientists must be able to
repeat your experiment with
similar results to prove it true.
Maggot Experiments Reproduced
• Anton von Leeuwenhoek
• Saw “animacules” with his
first microscope
Maggot Experiment Reproduced?
• John Needham
• Boiled sealed gravy
• Said heat killed any
organisms
• After several days little
animals came from the gravy
Maggot Experiment Reproduced
• Lazzaro Spallanzani
Nonliving
gravy did not
produce
living things.
Maggot Experiment Reproduced
• Louis Pasteur Flask was open to air,
but microorganisms could not make
their way into the flask
Maggot Experiment Reproduced
Proved
• Louis Pasteur Flask was open to air,
spontaneous
but
microorganisms could not make
their way into the flask
generation was not
correct.
When Experiments
are Not Possible
• Observing animals in
the wild without
disturbing them
• Determining the effect
of a chemical on a
cancer patient
THEORY
• Well-tested explanation that
unifies a broad range of
observations
• EX: biogenesis = life
generating from life
Theory is not..
• Considered absolute truth.
• Often revised or replaced as new
evidence appears.
rtame is marketed as
Sweet, Equal Spoonful,
via, NatraTaste
So refreshing, so delicious, so fun
• Coke and Mentos Fountain at
EepyBird.com (click here)
Aspartame is made of:
• 50% phenylalanine
• 40% aspartic acid
• 10% methanol (wood alcohol).
– In the body methanol breaks down into
formaldehyde (embalming fluid) and formic
acid.
Possible Side Effects
•
•
•
•
•
Blurred vison
Ringing in ears
Dizziness
Anxiety
Headaches/
migraines
• MS, lupus,
fibromyalgia, ADD
How to get rid of the aspartame
that is in the body.
• Milk thistle, vitamin C, selenium,
beta carotene , vitamin E, and Nacetyl-cysteine (NAC) are all
powerful antioxidants which are
helpful in liver detoxification.
Research
• Ralph G. Walton, M.D.
NEOUCOM
• Peer Reviewed aspartame studies
• (you analyze the studies)
How can we find what is true about
aspartame
• Inductive reasoning
• moving from the
specific to the general
• EX: Every time I drink
Diet Coke, I get a
headache.
• Deductive reasoning
• begins with the
general and ends with
the specific
• Diet Coke is
unhealthy due to the
aspartame breaking
down to
formaldehyde.