Transcript The Scientific Method

The Scientific Method
The Scientific Method
• An organized way to solve a
problem through experimentation &
observation.
The 6 Steps of the Scientific Method
1. State the Problem
• Form a question about a
specific event
Example: Mouthwash kills
bacteria. Which brand
works best?
2. Collect Information
• Research the problem
Example:
Read the labels of types of mouthwash
Which has the most antiseptic (germkilling) ingredients.
3. Form a hypothesis
• Make a testable educated
prediction based on your
research.
A hypothesis can be recognized
by an “if, then” statement.
Example: IF Listerine has more antiseptic
ingredients than Crest or the Wal-Mart brand,
THEN it will kill more bacteria.
4. Design an Experiment
• Create a way to test your
hypothesis.
Create a CONTROLLED experiment.
• A controlled experiment MUST have
2 groups.
CONTROL GROUP: all conditions
remain the SAME! It is a group you do
not do anything to.
EXPERIMENTAL GROUP: a group or
many groups who you test.
The experiment is performed on this
group.
• Establish the variables for your
experiment.
INDEPENDENT VARIABLE: the
variable that you change or
manipulate (X axis for graphing)
DEPENDENT VARIABLE: the
change or result that happens when
the independent variable is used (Y
axis for graphing)
Mouthwash Experiment
Control Group
-no mouthwash
Petri dish
Bacteria grown
from swab
Listerine
Experimental
Group
Crest
Brand
Wal-Mart
brand
Mouthwash Experiment
INDEPENDENT VARIABLE:
Type of Mouthwash
DEPENDENT VARIABLE:
Amount of bacteria killed
5. Collect & Analyze Data
• Run the experiment &
document the data
• 2 Types of Data
QUANTITATIVE: numerical data,
deals with specific quantities, usually
in the form of a graph or chart
QUALITATIVE: descriptive data,
describes how something looks,
smells, sounds, or feels; deals with
qualities
QUALITATIVE EX: The control group and
the Wal-Mart brand have a strong smell;
the Listerine & Scope don’t smell as bad.
QUANITATIVE EX:
Area of Inhibition for Mouthwash Brands
5 min
10 min
15 min
20 min
Control
Listerine Scope
Wal-Mart
0 mm
0 mm
0 mm
0 mm
3 mm
4 mm
6 mm
8 mm
1 mm
3 mm
4 mm
4 mm
2 mm
3 mm
5 mm
6 mm
6. Draw Conclusions
• Determine from the data collected if
the hypothesis was correct or
incorrect
EX: Listerine did kill more bacteria
than the other brands because it had
more antiseptic ingredients.
Scientific Method Vocabulary
• Observation- the act of observing
(touch, taste, smell, feel, see, etc.)
• Inference- a quick conclusion that
attempts to explain an observation
• Prediction- to forecast; to guess the
outcome of a situation beforehand
• Analysis- to separate or break apart
into smaller sections for study
Scientific Method Vocabulary
• Conclusion- to close or bring to an
end; to accept or reject a hypothesis
in an experiment
• Data- recorded observations or
measurements
• Hypothesis- a tentative explanation
that accounts for a set of facts & that
can be tested by further investigation
Scientific Method Vocabulary
• Controlled Experiment- an
experiment in which all variables
except the ONE being tested are
identical in order to make the
experiment fair & the results reliable
• Variable- any factor in an
experiment that could affect the
results & is therefore tested
separately
Scientific Method Vocabulary
• Controlled Variable- a variable that
is not changed
• Independent Variable – a variable
that you purposely manipulate
(manipulated variable)
• Dependent Variable- the variable
being observed that changes in
response to the independent
variable (responding variable)
Scientific Method Vocabulary
• Quantitative Data- data that
involves numbers or measurement
usually in the form of a chart or
graph
• Qualitative Data- anecdotal or
descriptive data that does NOT
involve numbers or measurement