Name:________________________________
COLOR LAB
Introduction
Our ability to perceive color depends on the physical properties on the object being observed
and the light environment the object is in. Additionally, the cells in the retinas of our eyes and the
interpretation of this information by our brains influences what colors we see. White lights – such as
sunlight and many types of indoor lighting – contain all the colors of the visible spectrum. As light is
reflected or absorbed, the reflected wavelength determines the perceived color. For example, a red
object reflects red light frequency and absorbs all others.
If the light environment has only a limited spectrum, colored objects will appear differently.
Under a blue light, a red object will absorb the blue light and appear black because there is no red light
to reflect back to the eyes.
Specialized cells for vision in the retinas of our eyes sense the reflected light: Rod cells sense
light intensity and cone cells sense color. The presence and distribution of retinal cone cells affect color
vision and differences in these cells explain color blindness, the decreased ability to perceive color
differences. Approximately 8% of men and 1% of women are affected by some degree of color
blindness. After perception in the retina, the light signal is conveyed as a nerve impulse back to the
brain’s visual centers.
Which of the above circles do you think would be difficult for someone with red-green color blindness to
see accurately?
TRIVIA: John Dalton, a famous scientist from the 18th century, was born with a rare form of color
blindness in which he was only able to perceive yellows. He was a pioneer in the research of color
blindness and was so passionate about his studies that he donated his eyes to science upon his death for
others to study. One of his eyes still exists today and is owned by the Manchester Literary and
Philosophical Society.
LAB PROCEDURES
There will be three stations set up with two to three marked cups of M&Ms (no eating please!), a
colored light, a stop watch, a paper plate and a flashlight. You will pair up with up to five other students
for the following procedures:
1. Predict what red will look like under different conditions. (Questions included below)
2. Once the lights in the room are off, turn on the lamp at your station.
3. Designate a group member to take the first turn sorting. Pick up the first cup and pour its
contents onto the paper plate, which should be positioned under the lamp.
4. When the sorter is ready, another student should start the timer while the sorter begins
removing the red M&Ms from the pile as fast as he can.
5. Stop the timer when the sorter thinks he has removed all the red M&Ms.
6. Using the flashlight, check to see if you have correctly identified all the red M&Ms or if you
missed a few.
7. Record the cup number, time, # of red removed, # of non-red removed, total removed and total
red in the data table.
8. Repeat these steps with each group member and for each different cup.
9. When instructed, move on to the next station and repeat these steps under a different light
condition.
DATA TABLE
AS A CLASS: WHITE LIGHT
Cup #
# of red
# of
nonred
Total
removed
Total red
Time
Selection
accuracy
%
Completion
accuracy %
PREDICT: What color do you predict the red candies will look like under red light?
STATION 2: RED LIGHT
Cup #
# of red
# of
nonred
Total
removed
Total red
Time
Selection
accuracy
%
Completion
accuracy %
PREDICT: What color do you predict the red candies will look like under blue light?
STATION 3: BLUE LIGHT
Cup #
# of red
# of
nonred
Total
removed
Total red
Time
Selection
accuracy
%
Completion
accuracy %
PREDICT: What color do you predict the red candies will look like under green light?
STATION 4: GREEN LIGHT
Cup #
# of red
# of
nonred
Total
removed
Total red
Time
Selection
accuracy
%
Completion
accuracy %
Name:_____________________________
COLOR LAB ANALYSIS
Directions: After finishing every station calculate Selection % Accuracy (# of red removed/ Total
removed) and Completion % Accuracy (# of red removed/ Total red) for each cup. Answer
questions and fill in the table below using the data your group collected.
Were your predictions about the apparent color of the red candy correct? If not, how did your
observations differ from your predictions?
Data Analysis Table
Light Color
Average
Time/Attempt
Average Time/Red
mm
Average Selection
% Accuracy
White
Red
Green
Blue
Average Time/Attempt = sum of time at station / # of attempts
Average Time/Red mm = sum of time at station / sum of total red mm’s
Average % Accuracy = sum of % Accuracy / # of attempts
Average % Total Red = sum of % Total Red / # of attempts
Average
Completion %
Accuracy
Directions: In Graph 1, use a line graph to graph Time vs. Cup # for each station. Label and
differentiate each line.
Directions: In Graph 2 use a line graph to graph Selection % Accuracy vs Cup # for each station
below. Label and differentiate each line.
Directions: In Graph 3 use a line graph to graph Completion % Accuracy vs. Cup # for each
station. Label and differentiate each line.
Directions: Use the data you collected and the graphs you’ve just created to answer the
following questions.
On average which station took the most time per attempt? Is this a good measure of how
difficult the station was? Why or why not?
On average which station took the most time per red candy? Why might this be a better
measure of the difficulty at this station?
Do you notice any trends in Graph 1? Hypothesize why there is or isn’t any noticeable trends
between time and cup #.