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Scientific Method
Scientific Method Steps
• State the problem.• Research the problem• Make a hypothesis.• Conduct the experiment.• Collect/analyze data.• Draw a conclusion.• Share your results
State the problem
• Problems arise from observations we make
Observations
• Observations: We use our senses to gather information about the world around us.
Hypothesis
• An educated guess• A prediction• Use “If”, “then” format
– We predict that if we drop a ball from a higher height, then it will bounce higher.• “If” is the Independent variable.• “Then” is the Dependent variable.
Experiment
• Must have a procedure– Step by step directions
• Must have only one variable– Thing that changes in experiment
• Everything else must be kept the same – Controls
Collect/Analyze Data
• Make a data table to collect results of experiment
• Make a graph (if possible)
Draw a Conclusion
• Use the data to either prove or disprove your hypothesis
Theory
• Has a very different meaning in science than in everyday life.
• “The detective has a theory about who robbed the bank.” This is a guess.
• When scientists use the word theory it is not used as a guess.
Theory defined
• An explanation based on many observations during repeated experiments that is valid only if:– it is consistent with observations – makes predictions that can be tested – It is the simplest explanation.
• A logical, time tested explanation for events that occur in nature.
Graphing
• The visual characteristics of a graph make trends in data easy to see.
• One of the most valuable uses for graphs is to "predict" data that is not measured on the graph.
Graphing Steps
• Identify the Variables
INDEPENDENT VARIABLE
D
E
P
E
N
D
E
N
T
V
A
R
I
A
B
L
E
Graphing Steps
• Identify the Variables• Determine the scale
INDEPENDENT VARIABLE
D
E
P
E
N
D
E
N
T
V
A
R
I
A
B
L
E
Graphing Steps
• Identify the Variables
• Determine the scale
• Number and label each axis
• Plot the points• Draw the graph
INDEPENDENT VARIABLE
D
E
P
E
N
D
E
N
T
V
A
R
I
A
B
L
E
Graphing Steps
• Identify the Variables
• Determine the scale
• Number and label each axis
• Plot the points• Draw the graph• Give graph a title
INDEPENDENT VARIABLE
D
E
P
E
N
D
E
N
T
V
A
R
I
A
B
L
E
TITLE
Identify the Variables
– Independent Variable - (the thing you changed)
Goes on the X axis (horizontal) Should be on the left side of a data
table.
– Dependent Variable - (changes with the independent variable)
Goes on the Y axis (vertical) Should be on the right side of a data
table.
Scale
– Determine a scale,(the numerical value for each square),that best fits the range of each variable.
– Spread the graph to use MOST of the available space.
Label Axis's
• You need to tell everyone reading your graph what the graph means.
• Be sure to include units.
Plotting
• Plot each data value on the graph with a dot. You can put the data number by the dot, if it does not clutter your graph.
Drawing
–Draw a curve or a line that best fits the data points.
–Most graphs of experimental data are not drawn as "connect-the-dots".
Title• Your title should clearly tell what
the graph is about.
• If your graph has more than one set of data, provide a "key" to identify the different lines
Interpolation
• Interpolate: predicting data between two measured points on the graph.
Extrapolation
• Extrapolate: extending the graph, along the same slope, above or below measured data.