# This Little Light of Mine

### This Little Light of Mine 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 be able to determine the line of best fit and eliminate incorrect equations. The student will observe the distance between the light source and the light probe which measures intensity.

Engage:Discuss with students the brightness of the city lights at night. Have students describe the purpose of sunglasses. Have students describe the differences in highway roads at night and the city streets at night.

Explore:
1. Students will mark off the sidewalk with colored chalk in 5 ft. increments for a total of 50 ft.
2. The teacher will move a car to the end of the markings( at 0 ft.) and turn on the low beam headlights.
3. Students will begin at the 50 ft. mark and move towards the car in 5 ft. increments until they are able to see that the bulb of the headlights is on. The student will then mark that distance on their data sheets. Each student will perform the activity.
4. After completion, the students will return to the 50 ft. mark and put on their sunglasses and repeat the experiment.
5. Next, the students will remove sunglasses, return to the beginning and the headlights will be increased to high beam.
6. Students will repeat numbers 3 and 4. NOTE: The experiment could be expanded by using different types of sunglasses and comparing the strengths of the shading of the sunglasses.
7. Students will have collected 4 columns of data at the end of the activity.

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: Students will perform the following experiment using the EA-100.
Equipment
meter stick
light source with dimmer switch
tape
light probe
wooden block 2" x 4"
EA-100
CFX-9850G
data communication cable
moving device - i.e. skateboard
blankets or black garbage bags for tunnel

1. Perform the experiment as follows:
• Have students use classroom furniture and blankets(or black garbage bags) to form a tunnel whose interior is completley dark and one end is open. The tunnel must be 2 m long.
• Place light source inside the tunnel in the middle of the darkened end. This is the rear of the tunnel.
• Place light source inside the tunnel in the middle of the darkened end. This is the rear of the tunnel.
• Mount the motion detector on the block of wood .
• Attach motion detector (on the block of wood ) securely to the moving device.
• Align the motion detector with the center of the light bulb so that the moving device always remains perpendicular to the rear of the tunnel and the cone of detection is aimed at the rear of the tunnel.
• Place a 2m piece of tape on the floor, perpendicular to the light source and rear of the tunnel.
• With another piece of tape, mark a starting line at 130cm from the light source. Mark an ending line at 50 cm. DO NOT CROSS THIS LINE!!!
• Put the moving device on the start line
• Turn on light.
• Connect the motion detector in the SONIC port of the EA-100.
• To operate the EA-100 manually, use the following keystrokes:
```KEYSTROKE 			EXPLANATION
a.  Press[SHIFT][MODE]		"Set-up"
b.Press [DATALOG] until "5 Sec" appears	"Next"  Press [DATALOG] several
times until the sample time you want
appears (5 Sec)
c.  Press[TRIGGER]		Chooses the 5 Sec as the time
d.  Press[DATALOG] until
"50" appears			Press [DATALOG] several times until
the number of sample points you want
appears (50)
e.  Press[TRIGGER]		Chooses 50 as the number of samples
f.    Press [DATALOG] until 1 appears	"Next" Press [DATALOG] until you see
the time consideration you want.  In this
case, the time will be collected as data.
g.   Press[TRIGGER]		Selects time consideration.
h.   Press[TRIGGER]		Begins sampling.  This means that it is time to move the moving device as directed.
```
2. When the student is directed to push the TRIGGER, IMMEDIATELY start rolling the moving device FORWARD, BACKWARD, FORWARD as many times as possible during the 5 second time interval.
3. Experiment is completed when EA-100 displays DONE.
4. 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
5. The data should now be listed in List 1 and List 2.
6. For the next part of the procedure you will be operating in the STAT menu.
a. After entering the STAT menu, you should find List 1 through List 2. Press GRAPH {F1}
b. Press SEL {F4}
c. StatGraph 1 : DrawOn
d. EXIT
e. 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 distance they are from the light source. 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. The students will be given new data and asked to create a new scatterplot graph and draw the line of best fit. Students will discuss the differences in light intensity as respect to sunglass usage and nonusage. For further classroom discussion, the different groups of students could each be given a different wattage of light and asked to plot the data using the same differences. Each group could be given an overhead transparency to plot their data and report it to the rest of the class.

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