## Mixing Colors

Science, Physical Science, Art, Mediums

### Objective

Students discover the possible combinations which result from mixing primary colors.

### Directions

Some objects, such as traffic lights and neon signs. appear colored because the light they give off contains a limited range of wavelengths. Most objects appear colored because their chemical structure absorbs certain wavelengths of light and reflects others. When white light strikes a banana, for example, it absorbs all other colors except yellow, which is reflected back to our eyes. The light entering the eye falls on the retina that lines the back and sides of the eyeball. Cells in the layers absorb the light and convert it to electrical signals. These travel through nerves to the brain where they are interpreted as color.
To prepare for the lesson, make sets of six plastic cups for each group, labeled as follows: red + green, green + blue, blue + yellow, red + yellow, blue + red, and yellow + green. Fill the cups nearly full of water. For each group, make a tray of the following materials: set of six cups of water, labeled with colors; six toothpicks; paper towel; one green and one yellow crayon; and two blue and two red crayons.
(If the activity is too complex for this class, arrange for adults or older students to work with each group as needed.)
Show the students red, green, blue, and yellow food coloring and have them tell you the names of the colors. Explain that they are going to use the food coloring in water and explain what they see happening. Divide the students into small groups and distribute a tray of materials to each group. Distribute a copy of the What Color Do You See? data sheet to each student and review it with them before they begin.
Divide the cups of water among the members of each group along with the food coloring and crayons which match the first color to be added to each cup. Assign each member of the group to do a different color combination in his or her cup of water, and then show the results to the other members so they can complete their records.
Have students compare the results of their experiments and complete the Color Chart work sheet as a culmination of the activity. After they complete the chart, students will use the cups of colored water they just created and add the third color as shown in the equation. To help them understand how to do this, have each group do the first combination as you monitor their progress. They will need to add yellow to the red + green cup and green to the red + yellow cup and compare the new color before writing the answer to the equation.

### Resources

• dropper bottles of red, green, blue, and yellow food coloring (one set per group)
• 9 oz. (260 mL) clear plastic cups (set of 6 per group)
• red, blue, green, yellow crayons
• toothpicks
• paper towels
• black permanent marker
• What Color Do You See? data sheet
• Color Chart work sheet