How Does the Ratio of Two Dyes in a Mixture Affect its Color?

Category: Mathematics—Ratio

Project Idea by: Easton and Weston Walker

Question: How Does the Ratio of Two Dyes in a Mixture Affect Its Color?

A ratio is a pair of numbers used to compare quantities. It can be expressed in three different ways: (1) in words, (2) with a colon, or (3) as a fraction. For example, the mixture of three parts of blue paint with ten parts of yellow paint would look like this:

A ratio is generally written as a simplified fraction. For the comparison of eyes to toes, you have two eyes and ten toes. The comparison of 2 to 10 would be simplified, so the ratio would be 1 to 5, 1:5, or 1/5. Order is important when writing a ratio. For the blue paint to yellow paint, the ratio is 3 to 10, not 10 to 3. Eyes to toes is 1 to 5, 5 to 1.

Paints, like other coloring materials, contain colorants. A colorant that dissolves in a liquid is called a dye. When dyes are mixed, a new color is produced. A project question might be, "How does the ratio of two dyes in a mixture affect its color?"

Clues for Your Investigation

Prepare two solutions using distilled water and two colors of food coloring. For example, if the dye colors to be used are blue and yellow, make testing solutions by mixing different ratios of blue and yellow. Make sure that each solution has the same amount of water. Design a method for mixing the dyes together in specific ratios such as by measuring out spoons of dye and pouring them into transparent cups. If the mixture is blue to yellow and the ratio is 1:2, then mix 1 spoon of blue dye and 2 spoons of yellow dye. Design a method of describing the color produced. One way is to compare the dyes with the color of the control, which is a 1:1 mixture. For example, a mixture of blue to yellow with a ratio of 1:1 is green. A mixture of blue to yellow with ratios of 2:1, 3:1, and 4:1 could be called light blue-green, medium blue-green, and dark blue-green, respectively.

Independent Variable: Ratio of dyes

Dependent Variable: Color of mixture

Controlled Variables: Measuring instrument, method of measuring color, dye solutions

Control: 1:1 dye ratio

Other Questions to Explore

1. What effect does the ratio of three or more dyes have on the resultant color of the mixture?
2. What effect does the ratio of dry colorants, such as colored sand, have on the resultant color of the mixture?

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