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Mixing Food Coloring: Blue and Yellow

Mix two colors of water—what happens?

Materials and Preparation

  • food coloring: Add blue food coloring to one bottle of water and yellow food coloring to another bottle of water
  • for each child: an ice cube tray, a cup of clear water, and two eyedroppers (one for each color)
  • paper towels or coffee filters (optional)

Key Science Concepts

  • A single color can have different shades, from very light to very dark.
  • Two or more colors can be combined to make a new color.
  • Diluting colored water with clear water creates a lighter shade of the same color.


Encourage children to use color names, as well as key terms such as color and shade; descriptive words such as light, lighter, dark, and darker; action words such as describe, drop, and mix; and science process words such as change, compare, dilute, observe, and predict. As they mix these colors, they may come up with names that reflect their observations, such as yellowish green or blue-ish green.


Tell children they will explore mixing two colors of water as they did yesterday—but this time they’ll mix blue and yellow; the colors in the story that they read earlier in the day. Ask them to predict what color will result, and why they predict that.

  1. Put the two colors of water into two different compartments at opposite ends of each child’s tray.
  2. Invite children to create different colors in their ice cube trays by using the eyedroppers to move drops of both colors into one compartment and watch the colors mix. As children work, ask:
    • What happened? How did the color change?
    • How did you make that color? How much (yellow) did you use?
    • Do you have any colors that are exactly the same? How are these two colors different? 

If they want, children can also add clear water to a compartment—a little bit or a lot. Talk with them about what they notice.

Reflect and Share

Talk about what children discovered in their color-mixing explorations. Have one or more of the ice cube trays containing the mixed-color water nearby so children can demonstrate their ideas.

Extension Idea

Children can place drops of blue and yellow food coloring on paper towels or coffee filters, recreating the image on the cover of Little Blue and Little Yellow.