Experimental Design Objectives 8'22'07

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Experimental Design Objectives8.22.07

• Students will be able to construct a line graph
  and a bar graph.
• Students will be able to determine which type of
  graph is most appropriate for graphing their
  data.
• Students will be able to explain the difference
  between a line graph and a bar graph.

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Analyzing and Graphing DataAgenda 8.22.07

• Complete the two starter activities (Analyzing a
  Data Table a Graph)
• Pass out a sheet of graph paper
• Objectives
• The Great Tomato Race-Collect Data Charts
• Four Corners Reading about Types of Graphs
  Activity
• Analyzing Data Activity (Reading a Chart and
  Graph)
• Describe whats happening in each trial
• Do you notice any patterns?
• Graphing Data Activity (Designing Graph)
• Drawing a Conclusion from the data
• Homework Refining Experiments Assignment, Graph
  Tomato Experiment data

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The Great Tomato Race

• Describe whats happening to the ketchup in all
  three trials.
• Do you notice any other patterns occurring.

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Four Corners-

• First you will be given 10 minutes to read an
  article about graphs
• Then, you will answer one question about graphs
  and then you will rotate counter clockwise to
  another area of the room where you will answer
  another question about graphs until you have
  completed all of the questions.
• You will be given 4 minutes to answer the first
  question, 3 minutes to answer the second
  question, and 2 minutes to answer the third
  question and one minute to answer the fourth
  question.
• After you finish, we will spend 4 minutes
  discussing your answer.
• You cannot repeat any information.

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The Four Questions about Graphs

• Tell me how to construct or make a line graph.
  (5)
• Draw an example of a line graph. (4)
• Tell me how to construct a bar graph. (3)
• Draw an example of a bar graph (2)
• When graphing data from an experiment, how do I
  know when to construct a bar graph? (1)
• When graphing data form an experiment, how do I
  know when to construct a line graph? (1)

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Construct a line graph together Homework on
8.22.07
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Construct Your Own Line Graph Homework on 8.22.07
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Constructing a Bar Graph Starter 8.23.07

• Would you use a bar graph or line graph to
  display the data above? Explain.
• Ask yourself the following questions
• Is the data comparing something?
• Is the change in color of the M Ms the direct
  cause for one color tasting better than the
  other?

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Steps in Constructing a Line GraphCopy these
into your notebook

• Identify the variables (I.V goes on the x-axis
  D.V. goes on the y-axis)
• Determine the range of the variables
• Determine the range of the two variables
• Determine the scale of the graph
• Number each axis
• Label each axis (include the appropriate units)
• Plot the data points
• Draw the line
• Add a title

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Determining When to Construct a line graph

• You must notice a cause and effect relationship
  between the two variables.
• A change in one variable must cause a change in
  the other.
• For example, dropping the tennis ball from
  different heights causes a change in the number
  of times that the ball bounces.
• The amount of time that a car is traveling causes
  the distance that a car travels to change.
• In determining whether or not you should
  construct a line graph, you must ask yourself one
  question?
• Does the independent variable cause the dependent
  variable to change?

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What do you think?

• Does the change in time in minutes (I.V.) cause
  the change in the adults pulse rate?
• Did this choose the right kind of graph to
  display the data?

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A line graph

• A line graph is used to show continuing data it
  shows how one thing is affected by another. It's
  clear to see how things are going by the rises
  and falls a line graph shows. This kind of graph
  is needed to show the effect of an independent
  variable on a dependent variable. In the sample
  below, the pulse rate of a person is shown to
  change over time. As time continues, the pulse
  rate changes.
• A typical chart or table for this graph might
  look like this

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Steps in Constructing a Bar Graph

• Identify the variables (I.V goes on the x-axis
  D.V. goes on the y-axis)
• Determine the range of the variables
• Determine the range of the two variables
• Determine the scale of the graph
• Number each axis
• Label each axis (include the appropriate units)
• Draw a vertical bar from the independent variable
  to the value matching the dependent variable.
• Draw the line
• Add a title

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How can I determine when to construct a bar graph?

• There is no direct relationship between the
  independent variable and the dependent variable.
• Data that compares information can typically be
  displayed as a bar graph. For example, a survey
  gathering information about which soda taste the
  best would be a good example of data that could
  be displayed as a bar graph.
• For example, the M Ms did not change whether
  people liked them or not. People have taste buds,
  which are sensitive to different taste. Some
  people like sour candy better than sweet candy.
  There is no direct relationship between the color
  of the M Ms and whether people like them or
  not. The color of the M Ms will exist whether
  people like them or not.

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Constructing A Bar Graphs

• Compare two unrelated things (Discrete)
• Bars typically dont touch

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What do you think?

• Does the independent variable cause a change in
  the dependent variable?
• Does the brand of fertilizer directly cause the
  bean plant to grow taller?

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The Answer Is.

• No, the fertilizer does not directly cause the
  bean plant to grow.
• Honestly if you placed the bean plant in the
  fertilizer without soil, sunlight, or water, the
  bean plant probably wouldnt grow.
• By mixing the fertilizer with water, soil, and
  sunlight, the plant changes the fertilizer into
  food that it needs to grow.
• So, bar graphs show how an independent variable
  can affect something indirectly.

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Conclusion of Lesson 8.23.07

• When constructing or making a line graph or bar
  graph, the independent variable is written along
  the x-axis. The dependent variable is written
  along the y-axis.
• In addition, the units of measurement must be
  recorded.
• When constructing or making a line graph or bar
  graph, the units or distance between each unit of
  measurement on the x-axis must be the same.
• When constructing or making a line graph or bar
  graph, the units or distance between each unit of
  measurement on the y-axis must be the same.

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How can I determine when to construct a line
graph or a bar graph?

• You will always construct a line graph when the
  independent variable causes a change in the
  dependent variable. This means that there is a
  direct relationship between the independent and
  dependent variables.
• You will always construct a bar graph when you
  are comparing information about two or more
  variables. This means that the independent
  variable may cause a change in the dependent
  indirectly. (Think about it. The fertilizer had
  to be turned into food before the plant could use
  it to grow.)

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Homework Graphing the dataExit Slip Turn in
before you leave (8.23.07)

• 4. Which type of graph would you use to graph the
  data? (line, bar, or pie graph) Explain your
  answer.
• 5. On a small sheet of graph paper, graph the
  data in the chart.

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Homework 8.23.07

• Remember to graph the Average, only
• Complete Practice Problems
• 1 A page 105
• 2 A page 106