Steps of Experimental Design:

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Steps of Experimental Design

• MM Investigation

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Well-Defined Questions
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Is it a WELL-DEFINED QUESTION??
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Is it a WELL-DEFINED QUESTION??
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Is it a WELL-DEFINED QUESTION??
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Is it a WELL-DEFINED QUESTION??
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Is it a WELL-DEFINED QUESTION??
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Is it a WELL-DEFINED QUESTION??
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Experimental DesignMM Investigation
HYPOTHESIS A hypothesis is an educated guess
about how things work.

• Most of the time a hypothesis is written like
  this "If _____I do this, then
  _____this_____ will happen.
• For example IF a plant receives fertilizer,
  THEN it will grow bigger than
• a plant that did not receive fertilizer.
• Other ways to write a hypothesis
• - I predict that ______________ because
  _______________.
• - I hypothesize that __________________
  because______________.
• Your hypothesis should be something that you can
  actually test.
• The word HYPOTHESES is plural for hypothesis.

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HYPOTHESIS

• Now write your own hypothesis based on the
  question
• Do some MM colors dissolve faster in water
  than others?
• Write your hypothesis behind the Hypothesis
  tab
• in your foldable.
• Remember
• - your hypothesis needs to be in an
  if/then statement
• - your hypothesis must be testable

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Examples of Possible Hypotheses

• IF the MM has a darker color, THEN it will
  dissolve faster.
• IF the MM has a lighter color, THEN it will
  dissolve faster.

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MATERIALS

• A materials list is important in
  organization and planning.
• It is important to list all materials you
  will need in order to carry out the experiment.

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MATERIALS

• Behind the Materials tab in your
  foldable, list all of the materials that you will
  be using in the MM Investigation lab.
• Materials
• White plastic plates
• Different colored MMs
• Water
• colored pencils
• a quarter
• Plastic cup, 3 ½ ounces
• Permanent marker
• Stopwatches

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VARIABLES

• Scientists use an experiment to search for cause
  and effect relationships in nature. In other
  words, they design an experiment so that changes
  to one item cause something else to change in a
  predictable way.
• These changing quantities are called VARIABLES.
• An experiment has 3 kinds of variables
• independent (manipulated), dependent
  (responding) and controlled (constants)

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INDEPENDENT VARIABLE

• The independent variable is the one that is
  purposely changed or manipulated by the
  scientist. To ensure a fair test, a good
  experiment has only one independent variable. As
  the scientist changes the independent variable,
  he or she observes the changes.
• Example
• Does the amount of fertilizer affect plant
  growth?
• The amount of fertilizer is the independent
  variable
• because the scientist has control over how
  much
• fertilizer is used in the experiment.

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EXPERIMENTS CAN HAVE ONLY 1 INDEPENDENT VARIABLE
Suppose that you wonder whether you can run a
marathon faster when you eat pasta the night
before or when you drink coffee the morning of
the race. Your hunch is that loading up on pasta
will give you the energy to run faster the next
day. The independent variable is the consumption
of pasta, and the dependent variable is how fast
you run the race. Now, if you eat several plates
of spaghetti the night before you race, but then
get up the next morning and drink two cups of
coffee before you head to the start line, your
experiment is useless. Why is it useless? By
drinking the coffee, you introduce a second
independent variable, so you will not know
whether the faster race time is due to the pasta
or the coffee. Experiments can have only one
independent variable. If you want to know the
effect of caffeine (or extra sleep or improved
training) on your race time, you would have to
design a second (or third or fourth) experiment.
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• What is the
• independent variable
• in your MM investigation?

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• Independent Variable
• MM Color

Why is MM color the independent variable?
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DEPENDENT VARIABLE

• The dependent variable is what is measured in the
  experiment.
• The scientist focuses their observations on the
  dependent variable to see how it responds to the
  change made to the independent variable.
• Example
• Does the amount of fertilizer affect plant
  growth?
• The dependent variable is plant growth.
• This can be MEASURED, and it RESPONDS to the
• change made to the independent variable.
• (amount of fertilizer)

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• What is the
• dependent variable
• in your MM investigation?

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• Dependent Variable
• how fast the MM colors dissolve

Why is the speed that the MM colors dissolve
the dependent variable?
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CONTROLLED VARIABLE (CONSTANTS)

• When conducting an experiment, all other
  variables must be kept the same throughout the
  investigation they should be controlled. The
  variables that are not changed are called
  controlled variables. (constants)
• Example
• Does the amount of fertilizer affect plant
  growth?
• Independent variable amount of fertilizer
• Dependent variable plant growth
• Controlled variables same type of plant, same
  pot size, same amount of water, same amount of
  sunlight

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DATA TABLES

• Tables are an excellent way to display data or
  information in an organized fashion.
• By putting data in tables one can easily from
  there set up a graph to illustrate the data.

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Tables have several features in commonFirst,
all tables as well as graphs should have a title
to let the reader know the subject of the table
or graph. Most tables consist of a series of
rows and columns.
TITLE
ROWS
COLUMNS
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GRAPHS

• A graph is a chart or drawing that shows the
  relationship between changing things
• Common graphs use bars, lines, or parts of a
  circle to display data.
• Graphs must include a title and labels on the x
  and y axis.
• Why will we use a bar graph in our MM
  investigation?

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Example of a Bar Graph
TITLE
Y-Axis Dependent Variable
X-Axis Independent Variable
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DRY MIX

• DRY MIX is an acronym to help you remember how
  variables are plotted on a graph. D dependent
  variableR responding variableY graph
  information on the Y-axis (vertical, up and
  down)M manipulated variable I   independent
  variableX  graph information on the X-axis
  (horizontal, side to side)