University of Virginia
Physics Department

Reflection

A Physical Science Activity

Student Activity

Materials

 

Procedure

  1. Divide students into groups of four. Throughout the exercise, each student will be assigned a specific job. It is the teacher's discretion to assign or to allow student choice with group jobs. The jobs include:
    • Mirror Holder - holds the mirror, maintaining the 90° angle; also reads lab instructions.
    • Recorder - writes for the group during the actual performance of the lab.
    • Penlight Operator - operates the penlight flashlight, maintains it at safe distances and angles away from eyes of group members; also is responsible for asking the teacher any questions that the group cannot figure out.
    • Chalkboard Eraser Operator - gently and lightly taps erasers together to illuminate the beam of light from the penlight; also picks up and returns all lab materials for the group.
  2. Neatly arrange materials at your lab stations and know object locations as this lab will be performed in a darkened room.
  3. Turn on penlights.
  4. Teacher darkens the room.
  5. One blank sheet of paper should be laid down on the table first and labeled #1 to indicate it is the first set of data.
  6. The Mirror Holder will rest one edge of the mirror on the sheet of paper, holding it perpendicular to the table at all times. (Use the protractor to measure and maintain the angle if necessary.)

  7. The Recorder will draw a line on the paper indicating the location of the front edge of the mirror, as indicated in the diagram below.
  8. The Penlight Operator will then hold the light a distance of one half the mirror's height above the paper's edge and shine the beam onto the center of the mirror at an angle.

  9. The Chalkboard Eraser Operator will gently and lightly tap the erasers over top of the experimental set up, allowing the dust to fall down into and illuminate the beam from the penlight.
  10. Looking down over the top of the experimental set up, the Recorder will quickly trace the path the beam takes onto the paper beneath it.

  11. Turn the paper over to the clean side and perform another trial by repeating steps 5-10. This time, label the data with a number 2, for the second set of data.
  12. Using the second sheet, repeat steps 5-9 two more times to obtain data sets 3 and 4.
  13. After all four sets of data have been collected, clean up your lab station and return to your group for analysis of the data.

 

Data Sheet

 

Discuss lab data with fellow group members, then record your answers in your own words.

*NOTE: For #s 1-4, allow a different member of the group to measure the angles in each question. The group will share this data.

 

  1. Using the protractor, measure the angle of incidence and the angle of reflection for data set #1. Record your measurements.

    Angle of incidence = ____________

    Angle of reflection = ____________

     

  2. Using the protractor, measure the angle of incidence and the angle of reflection for data set #2. Record your measurements.

    Angle of incidence = ____________

    Angle of reflection = ____________

     

  3. Using the protractor, measure the angle of incidence and the angle of reflection for data set #3. Record your measurements.

    Angle of incidence = ____________

    Angle of reflection = ____________

     

  4. Using the protractor, measure the angle of incidence and the angle of reflection for data set #4. Record your measurements.

    Angle of incidence = ____________

    Angle of reflection = ____________

     

  5. Reporting your results: On the back of this sheet, create a chart which will adequately display your lab results.

     

     

  6. What mathematical principal or truth can you arrive at using your data and that of your classmates?

     

     

     

  7. In a well written paragraph, explain how the basketball model relates to the behavior of light that you observed in the lab.