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Color Taste Test—Do You Taste with Your Eyes?

20 reviews


Active Time
20-30 minutes
Total Project Time
20-30 minutes
Key Concepts
Sensation, perception, taste
Megan Arnett, PhD, Science Buddies
Ben Finio, PhD, Science Buddies
Three cups filled with red, green, and blue liquid


Have you ever tried adding green food coloring to your milk? Or blue coloring to the butter you spread on your bread? You may not have tried this, but for years, scientists have studied the effect of color and food appearance on how food tastes. Believe it or not, our eyes are an important part of how we taste and perceive food! In this activity, you will learn about how you can trick your taste buds—with just a little food coloring!

This activity is not recommended for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


  • Apple juice
  • Red, green, and blue food coloring
  • Drinking glasses (at least 5)
  • Water
  • Volunteers

Prep Work

Note: It is important that your volunteers do not know that there is apple juice in each cup! The idea is that your volunteer should expect something different in each cup. Therefore, do not let them see you prepare the drinks ahead of time!
  1. Pour a small amount of apple juice into each of four drinking glasses.
  2. Put a drop of red food coloring into one glass, a drop of blue food coloring into the second glass, and a drop of green food coloring into the third glass.
  3. Swirl the glasses to mix the food coloring in. Add another drop of food coloring if the colors are not dark enough.
  4. Leave the fourth glass with no food coloring.
  5. Fill the fifth glass with water.
If you have more drinking glasses, prepare them the same way in sets of five (five for each volunteer). Otherwise, you will need to wash, rinse, and dry them in between volunteers


  1. Set out all five glasses for your first volunteer.
  2. Ask them to start by drinking some water to cleanse their palate.
  3. Tell your volunteer to sample the colored drink in each glass one at a time, drinking water in between each one.
  4. Ask your volunteer which drink was their favorite.
  5. Now ask your volunteer to close their eyes. Hand them the cups one at a time to taste again, in a random order. Ask them which one is their favorite (based on the initial order—e.g. first cup, second cup...).
    Think about:
    Did they pick the same cup as the first time?
  6. Now, reveal your secret! Tell the volunteer that each cup contains apple juice. Ask them to sample each cup one more time, with their eyes open.
    Think about:
    Do they still have a favorite, or do they all taste the same?
  7. Repeat steps 1–6; with your other volunteers.
    Think about:
    Does one color seem to consistently be the favorite for your volunteers? How do they react when they find out all the cups are apple juice? Did anyone figure it out on their own?

What Happened?

In this activity, you tested whether the color of a liquid impacted your volunteer's perception of the liquid's taste. Despite the fact that each cup contained the same thing (apple juice), you probably found that your volunteers preferred the taste of one cup over the others. Since the only difference between the liquids was color, we can determine from this activity that the appearance of the liquid does affect how it tastes.

If your volunteer noticed that the cups all contained the same thing, compliment them on their acute taste perception! We rely so heavily on visual information, it often influences how we perceive information coming from all of our other senses. If your volunteer was able to separate the visual information from what they were tasting, their perceptions are especially sharp!

Digging Deeper

The taste buds on your tongue detect flavors and food groups, and help you identify the foods you eat. However, other senses play a role in how we experience food. You probably know that the aroma of foods can have a strong effect on how they taste, but did you know that the appearance of food also changes how we experience it? Because we usually look at food before we put it in our mouths, the very first information your brain gets about any particular food comes from your eyes!

From an early age, we learn to associate colors with flavors. When something is orange, we expect an orange flavor. If you tasted green pudding, you would be surprised to find that it had a cherry flavor. Discrepancies between the appearance of food and their taste can make it more difficult to identify the flavoring.

Research has shown that the appearance of food can dramatically affect how it tastes. In one study, participants ate a plate of normal-looking steak and French fries. All the participants said they enjoyed the food, and it tasted fine. However, when the lights were brightened, it was revealed that the steak was dyed blue, and the fries were dyed green. When they saw this, many of the participants refused to eat any more of the food, and a few even grew sick!

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For Further Exploration

  • Ask your volunteers to rate their favorite and their least favorite drink. Are some colors more appetizing than others?
  • Try this experiment with other liquids like milk, or with solid foods.

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