Taste Buds

Objectives

Concepts:

• “Taste” has to do with the kinds of flavors we experience in the foods we eat and the liquids we drink.

• “Taste buds” are little organs all over our tongues that interpret or pick up the sense of what flavors are in our food and drinks.

Facts:

• Our tongues have four basic types of taste buds: bitter, sour, salty, and sweet.

• Our taste buds are located in specific areas on our tongues.

Principles:

• Eating would be pretty boring if we didn’t have taste buds! Everything would taste the same.

• Most insects use their mouths to taste flavors just as we do. But some insects can use other parts of their bodies to taste with, too! For example, a butterfly tastes food with its mouth and its feet. Ants can taste food with their mouths and with their antennae.

• People can only taste food and liquids with the taste buds in their mouths. But we sense flavors by using our sense of smell, too!

• We also have a few taste buds on the lips (especially salt-sensitive ones), the inside of the cheeks, the underside of the tongue, the roof of the mouth, and the back of the throat.

Skills:

• Making Observations
• Communicating Findings
• Making Inferences
• Drawing Conclusions

Materials:

1. Lemon juice
2. Sugar
3. Salt
4. Powdered instant coffee
5. Cups to label and put these food materials in
6. Toothpicks
7. Handout
8. Pencils

Room Preparation

Just need elbow room!

Safety Precautions

Be careful not to get the food items in your eyes. If you do, rinse out thoroughly with cold water.

Procedures and Activity

Introduction

Ask the guiding questions:

1. What are taste buds?

   First, talk about taste. Share information about different foods and liquids that are sweet, salty, sour, and bitter. You might write down these categories on a blackboard or piece of paper and jot down their examples.

   Why don’t all foods and liquids taste the same? Wouldn’t it be boring if everything did taste the same?

   Introduce concept of little organs on our tongues called taste buds and how these sense and communicate to us different flavors.

2. Where are the buds for particular tastes located?

   Our experimentation will show that taste buds are not evenly distributed over the tongue. Certain tastes are experienced more intensely in some areas than others.

Today, we are doing an experiment to help us figure out where our different taste buds are located on our tongues.

Activity

1. Give each person or pair:

   • 4 cups labeled and containing salt, sugar, lemon juice, and instant coffee
   • Toothpicks
   • Handout
   • Pencil

2. Look at the handout and talk about the shape of our tongues. Take time to think about how we are going to describe where we taste different flavors—tip of tongue, back of tongue, sides or edges of tongues. On the sides or edges, we can break it down to more towards the front or more towards the back of the tongue.

3. Use a toothpick to apply lemon juice to the tip, back and sides of the tongue. Think about what area of the tongue responds to the sour flavor of the lemon juice. Put a check in the box on the chart on the handout where you think you sensed the sour flavor of the lemon juice.

4. For powdered materials, you may need to lick your toothpick before you dip it into a cup to get a sample. Dip the toothpick into the powdered coffee and experiment with dabbing it on your tongue in different locations. Where do you pick up the bitter flavor of coffee? Put a check in the box on the chart where you sensed the coffee’s bitter flavo.

5. Dip the toothpick into sugar. Again, experiment with dabbing sugar on different locations of your tongue. Where do you pick up a sweet flavor? Put a check on the box on your chart.

6. Dip toothpick into salt (you may need to lick the toothpick first!) Try dabbing salt on your tongue. Where do you really pick up a salty flavor and taste? Check the box on your chart.

Closing - Original Question

Ask again,

1. What are taste buds?

2. Where are our taste buds located on our tongues?

Share the information they gathered from doing their experiments. On what part of the tongue did we sense salty, sweet, bitter, and sour flavors?

Evaluation

1. Let them share their information about taste buds with someone else. Encourage them to help others repeat the experiment.

2. During discussions, listen for evidence that they understand we sense flavors due to taste buds located on our tongues and that taste buds are located in special areas of the tongue.

Extension Ideas

1. Repeat the experiment, but this time plug your nose! You will find that our noses help us detect flavors.

2. Pick out an insect or other animal to research and study. How does it detect flavors in foods and liquids? Ants and butterflies are fun to learn about.

3. Find further information at these sites:

   • That’s Tasty from U. Washington’s Neuroscience for Kids site also has links to other, more technical info about taste.
   • Stick Out Your Tongue and Say Aah!
   • Check out the fifth kind of taste bud that the Japanese call umami, described as the taste of meat, for which researchers have recently found molecular evidence: “Discovery Supports Fifth Taste Bud” from the University of Miami, “A taste for umami” (very technical!) from Nature Neuroscience, and the Wikipedia article on it. There is even an Umami Information Center!

Careers Related to Lesson Topic

• Chef
• Dietitian/Nutritionist
• Food Processor
• Agricultural and Food Scientist
• Food Service Manager
• Biologist

Prerequisite Vocabulary

Taste

The flavor and sensation of food and liquid.

Taste buds

Little organs found on the tongue that sense and communicate different flavors in foods and liquids. The main types of flavors and sensations are sweet, salty, bitter, and sour.

Why is there no “Answer Key”?

Such maps of our tongues do exist, but we choose not to provide one. First, there is too much individual variation (and variation over the course of your life, as you lose taste buds) for a single, accurate answer key. But primarily, we choose not to provide the “right answers” because that would undermine the purpose of these activities, which is to communicate not so much specific knowledge as the process of doing science: observing carefully, forming hypotheses, and drawing conclusions based upon your own experimental data. A good scientist does not waste time asking questions that she already knows the answers to, and she tries mightily to avoid interpreting her data to fit a foregone conclusion.