Unit 1a The scientific method Or never say I have a theory The scientific method Pattern of logical investigation involving stating a problem forming a hypothesis researching and gathering information testing a hypothesis analyzing data drawing conclusions ID: 779563
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Slide1
Warm-up
What should you do if you see a fire in the lab?
Slide2Unit 1a: The scientific method
Or, never say, “I have a theory!”
Slide3The scientific method
Pattern of
logical
investigation
involving stating a problem, forming a
hypothesis
, researching and gathering information, testing a hypothesis, analyzing data, drawing conclusions.
A way of
thinking
Not restricted to
science
Can’t use the scientific method for
everything
Slide4hypothesis
A
testable
, possible
explanation
for a problem using what is known and what is observed.
An untestable hypothesis = a
BAD hypothesisExample: “I think this electronic box on the wall controls the room temperature”
Slide5Good or Bad hypothesis?
Love is the most important thing in the universe.
Love is claimed by most people to be the most important thing in the universe.
Chocolate is the best tasting substance in the world.
People exposed to chocolate in their culture are more likely to enjoy it.
Bananas outperform Gatorade as a recovery food/drink after a marathon.
Before the universe existed, there was a giant walrus whose consciousness was the only thing that existed.
Slide6experiment
Organized procedure for
testing
a hypothesis; tests the effect of one thing on another under
controlled
conditions
Slide7variable
Quantity
that can have more one value. Can
change
in an experiment.
Examples: thermostat settings, room temperature, humidity, etc.
OFF
65°
85°
Slide8Dependent variable
Factor that
changes
as a result of changes in
other
variables
Example: the temperature of the room
72°
Slide9Independent variable
Factor that, as it changes,
affects
the measure of
another variable
Usually what
you manipulate
Example: thermostat setting
Slide10Graphing variables
Use “DRY MIX” to remember
D
:
Dependent
M
: Manipulated
R
: Responds
I
:
Independent
Y
: Y-axis
X
: X-axis
Set temperature
Actual temperature
Slide11constant
In an experiment, the variable that
does not change
Example: humidity,
size of room
. Size of AC unit.
Room 2
Room 1
Slide12control
Standard
used for
comparison
of test results in an experiment.
Example: room with no thermostat.
Room 2
Room 1
Slide13bias
Occurs when a scientist’s
expectations
change how the results of an experiment are
measured
or
viewed
.Example: scientist subconsciously ignores or exaggerates data
Slide14model
Used to
represent
an idea object, or event that is too big, too small, too complex, or too dangerous to observe or test directly.
Example: a circuit
diagram
of the thermostat or a computer
simulation of a thermostat controlling the temp.
Slide15Scientific theory
Explanation
of things or events based on knowledge gained from
many
observations, investigations, and experiments.
A theory is NOT a hunch!!!
Explains
the how
or the
why
.
Slide16Scientific law
Statement about
what
happens in nature that seems to be
always
true
under certain conditions; does not explain why or how
something happens.
Examples: the law of gravity versus the theory of gravity.
Slide17Theories
DO NOT
become laws!
Laws
are not
“better” than theories
Slide18GRAPHICAL REPRESENTATION OF DATA
How to make your data speak, and how to read it
Slide19Cartesian plots
Remember “DRY MIX”:
X-axis:
maniupulated
, independent
Y-axis: responding, dependent, what is measured
Slide20Line graphs
Data points are connected by lines
Used for
many
data points of
continuous
data (often time) on the x-axis
Slide21Line graphs
Slide22Bar graphs
data point magnitude on
y-axis
represented as
vertical bar
/line
Used for plotting
non-continuous data, or continuous data with
few
data points, on x-axis, such as ice cream flavors, brands of shoes, color of light, seasons of year
Sometimes a bar graph or a line graph could be used to represent the same data
Slide23Bar graphs
Slide24Bar graphs
Slide25histograms
special line/bar graphs where y-axis represents the
frequency
of a measure (
how common something is
)
Frequency can be represented as number, fraction, percentage, proportion
Usually dependent variable values are put on the y-axis, but here the
frequency
of values (or a range of values) is placed on the y-axis. [“DRY MIX “does NOT apply]
Typically there is no space between the bars
Examples: IQ chart, height of people in population, grades on an exam, lifespan, “bell curve”
Slide26histograms
Slide27histograms
Slide28histograms