Buddy and Mr. Pteranodon

Testing Hypotheses While Color Mixing

Investigate the science of color while learning and using the word “hypothesis.”

Before You Play

Explain to your child that “hypothesis” is a word that scientists use for “an idea that you can test.” You could also add, “A hypothesis is a kind of prediction.” Give some examples, such as, “If I drop this rubber ball on the floor, my hypothesis is that it will bounce.” Or, “When I see dark clouds in the sky, I have a hypothesis that it will rain soon.” Encourage your child to come up with a simple hypothesis or two, then ask, “How could you test your hypothesis?”


  • Primary color food coloring (red, blue, yellow)
  • Water
  • Six empty, clean baby food jars (or similar clear containers)
  • Three eye droppers
  • Rimmed cookie sheet
  • Colored markers (at least 8 colors)
  • Plastic spoon
  • A Colorful Hypothesis (PDF)


  1. Begin by filling three empty baby food jars with water. Add drops of food coloring to each jar until each is a primary color: red, blue, and yellow. Fill the other three jars with water. Put all materials on a rimmed cookie sheet.
  2. Invite your child to join you for a color experiment: mixing different colored water together to find what new color is made. Before your child mixes any color, ask them to make a hypothesis about the new color. In other words, they will guess what the new color will be. Point out that sometimes a hypothesis is right, and sometimes it is wrong. Either way is no big deal. Remind your child that Buddy sometimes tests his hypotheses and discovers that his guess was wrong. The important thing is to make your best guess and learn from the results.
  3. Use the “A Colorful Hypothesis” printable to explain that you will be recording your experiment and hypotheses together. Show your child the chart’s example of mixing five drops of blue with five drops of yellow.
  4. Time to start mixing and hypothesizing! Use markers to write your experiments and hypotheses on the observation chart. Then help your child to put drops of each colored water in the clean water jars and see the results. Repeat until the chart is full.
  5. Optional: An older child can try this experiment backwards by first creating a new shade of colored water. Then you, another adult, a sibling, or friend can try to figure out how this color was created.

This activity comes to you from the creators of Dinosaur Train.

Iowa PBS STEAM Activities and Crafts provided by PBS KIDS Parents.