Are You Afraid Of the Dark?

Maxine Edwards and Mary Teal
The Center for Advancement of Teaching

Are You Afraid Of the Dark?
Lesson Plan
Algebra 1 Level

Objective:The student will be able to plot data on a scatter plot graph and interpret the information found there. The student will observe the change in light intensity over the given time interval.

Engage: Discuss with the students the different amounts of sunlight received on the earth during a 24 hour period. Discuss how you see and the reactions of the eyes depending on the amount of light present. Examples - Movie theaters- Do the lights in the theater get suddenly dark or is there a gradual lessening of the light? Can you see better in a dark room as the length of time spent in the room increases?

  1. Have students stand in a large circle . Try to keep all students equal distance from the instructor who is standing in the middle of the circle
  2. Give each student a piece of black construction paper with white letters pasted to it. Give the paper to the students FACE DOWN, so that the students do not know what the word is. Student should also have writing utensil and the attached data sheet.
  3. The instructor will stand in the center of the circle holding a light source with a dimmer switch attached to it. Initially the light should be set at the lowest level of light.
  4. Turn off classroom lights.
  5. Students should turn their construction paper over to be face up.
  6. The instructor should begin counting ( as evenly as possible to simulate passing seconds), beginning with 0 and ending with 29. With each increase in numeric value, the light intensity should increase. At the number 9, the light should be at its highest intensity. As the instructor continues to count, the light intensity should decrease, reaching its lowest level at 19. The instructor should continue to count, increasing the intensity to its fullest, to the maximum of 29. (Note: Since this experiment deals with light intensity, it is important that the instructor be seated with the light source unblocked for all students)
  7. As the instructor counts, using the data sheet, the students should individually record either Y or N at each number level to determine if they are able to read the written words or letter on their piece of construction paper. Each student should have a list of 30 numbers and answers at the end of the experiment.

Explain: Discuss light intensity.
Break students into groups of 4. Each group will be responsible for collecting all data and making scatter plot graphs for each column of data from all members of the class. Scatter plot graphs could be done on transparencies to share with the class as well as overlaid to see any differences and similarities. This would confirm to all students whether they have correctly graphed the data.

Elaborate: Discuss light intensity. Upon completion of the experiment, have the students break into groups of 4 to plot their individual data. All graphs should be marked using the x-axis for the time in seconds as given by the instructor, and the intensity of the light as the y-axis.
(Note: So as not to confuse the students, the instructor will note that the data sheets have been premarked with intensity levels . The levels have been marked using letters of the alphabet. These could easily be replaced by actual wattage amounts if known . For this particular experiment the resultant graph was the topic for discussion, therefore the labels for the y-axis needed to be predetermined to ensure the configuration of the graph.) Each group will be responsible for presenting scatter plot graphs on transparencies to share with the class. Each transparency would represent data for the combined group with the line of best fit drawn in. Each group graph could be overlaid to see any differences and similarities. This would confirm to all students whether they have correctly graphed the data. Conduct activity using the EA-100 and CFX-9850G.
    light probe
    Wooden block
    light source with dimmer switch attached
    blankets or black garbage bags - for tunnel
    meter stick
    Data communication cable

  1. Perform the experiment as follows:
  2. Retrieve the data from the EA-100:
    a. Connect EA-100 to CFX-9850G using the data communication link.
    b. Turn on CFX-9850G and choose Run (1) from the menu.
    c. Press SHIFT VARS {PRGM}
    d. Press F6 (>) , then I/O {F4}
    e. Press Recu (F4) {Receive( }
    f. Press OPTN, List {F1}, List {F1} ,1, close Parenthesis { ) }
    g. Press SHIFT EXE { }
    h. Press Recu (F4) {Receive( }
    i. Press OPTN, List {F1}, List {F1} ,2, close Parenthesis { ) }
    j. Press EXE
  3. The data should now be listed in List 1 and List 2
  4. For the next part of the procedure you will be operating in the STAT menu.
    e. After entering the STAT menu, you should find List 1 and List 2. Press GRAPH {F1}
    f. Press SEL {F4}
    g. StatGraph 1 : DrawOn
    h. EXIT i. Press SET {F6}
    Graph Type: xyline
    Xlist : List 1
    Ylist : List 2
    Frequency : 1
    Mark Type :
    Graph Color: CHOICE
    f. EXIT
    g. GRPH 1 {F1}

    Evaluate: Students will write and explain the intensity of the light with respect to the time the light is recorded. Also the students will be able to explain the relationship of the x and y axis and why the data is only in the first quadrant. Students will explain the relationship of the intensity of the light and the wattage of the light source. Further experiments could be conducted by changing the wattage of the light source . The students will be given new data and asked to create a new scatterplot graph and draw the line of best fit.

    Developed by:
    Maxine Edwards and Mary Teal
    Butler High School Matthews, NC

    additional help from:
    Neal Farley
    Independence High School
    Charlotte, NC