Our Sense of Taste
© Keddie De Cojon.
- Grades:
- K-2
- Length: Variable
Overview
Students taste four mystery substances and learn that the tongue is covered with taste buds, which contain taste receptors that communicate with the brain, and that the brain determines the flavors we experience.
This activity is from K-1: The Senses Teacher's Guide. While designed for students in grades K-1, it may be used with students in Pre-K and grade 2.
- Teacher
Background - Objectives and Standards
- Materials and
Setup - Procedure and
Extensions - Handouts and
Downloads
Teacher Background
Why does chocolate ice cream taste delicious and sour milk taste awful? Scientists believe that taste evolved to help identify potentially nutritious foods and avoid eating things that are harmful.
Taste begins in our mouths, with the chemical receptors that dot our tongues. The tongue’s surface is coated with thousands of small bumps, called papillae. Each papilla holds approximately 10,000 taste buds, which renew themselves about every 10 days, unless they are damaged by infection or smoking. Each taste bud contains 50–150 taste receptor cells.
When you eat, saliva dissolves certain chemicals from the food. The chemicals enter openings in your taste buds and interact with taste receptor cells. The receptor cells send signals to the brain, where they are combined with information from the sense of smell to create what you experience as flavor.
We generally recognize four tastes: sweet, sour, salty and bitter. A fifth taste, umami (savory) occurs when we eat foods with glutamate (like MSG). Bacon, mushrooms and fermented foods, such as cheese and soy sauce, are rich in umami. Beyond allowing us to taste, the tongue can sense pressure, temperature and pain. That’s why we are able to experience certain
foods as spicy or minty, and distinguish among different food textures. The sense of smell also contributes to the flavors we experience. Odor qualities, such as floral, fruit, burnt or putrid, shape our food-related sensory experiences.
Some people, called “supertasters,” have more taste buds than average and are highly sensitive to certain tastes. One’s genes can make him or her more sensitive
to certain tastes, as well. And over time, many people experience a change in taste sensitivities. That’s why adults sometimes become more tolerant of—and even enjoy— foods, such as broccoli or Brussels spouts, that they avoided as children.
Many older textbooks feature a “map” of the tongue with different regions specialized for particular tastes, such as sweet or sour. This interpretation of the distribution of taste receptors is inaccurate. In fact, receptors for all tastes are distributed throughout the tongue, and even are present in other areas of the mouth.
Objectives and Standards
Guiding Questions
What are the basic tastes? Where is information about taste detected in the body?
Concepts
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All of the senses are connected to the brain.
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Our senses let us know what is going on inside and outside our bodies.
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One of our senses is taste.
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The tongue is covered with taste buds, which contains taste receptors.
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Taste receptors communicate with the brain, which determines the flavors we experience.
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Taste buds detect sweet, sour, salty, bitter and umami (savory) tastes.
Materials and Setup
Part 1
Teacher Materials (See Setup)
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16-oz bottle of lemon juice
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1/4 cup of sugar
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1/4 cup of salt
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Classroom human body diagram (see Activity 2, “The Brain: Protection”)
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Marker
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Water
Materials per Student
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4 crayons or markers
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Set of labeled portion cups containing 1/8 tsp of the following substances: salt in cup 1, sugar in cup 2, water in cup 3, and lemon juice in cup 4.
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2 cotton swabs (Q-tips® style)
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Plastic spoon
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Plain paper or foam plate
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Small hand mirror
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Science notebook
Part 2
Teacher Materials (See Setup)
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16-oz bottle of lemon juice
Materials per Student
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6 plastic spoons
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4 plastic cups half-filled with water
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1/2 cup of sugar
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1/4 cup of lemon juice
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Tray
Setup
Part 1
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Prepare a set of four portion cups, labeled 1, 2, 3 and 4. Place 1/8 teaspoon of each of the following substances into the cups: salt in cup 1, sugar in cup 2, water in cup 3, and lemon juice in cup 4.
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Place each set of cups, along with two cotton swabs, on a plate for each student.
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Have students work in groups of four, with their own set of materials.
Part 2
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Prepare a half-full cup of water for each student.
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Place the cups of water, 1/2 cup of sugar, 1/4 cup of lemon juice and six spoons on a tray for each group.
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Have students work with shared materials.
Safety
Have students wash their hands before and after the activity. Instruct students not to share cotton swabs.
Procedure and Extensions
Time
Two sessions of 30 minutes
Part 1
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Ask students to think about their favorite flavors. Conduct a short class discussion about the foods they mention. Students will probably share foods that are sweet, salty, and sour; but they may describe complex combinations of flavors. Explain that you will create a class “taste” chart. Draw a table on the board and list “Sweet,” “Sour” and “Salty” across the top. Note that the tongue can detect two additional tastes: bitter and umami (savory). Bitter is more common, and can be detected easily, so add a “bitter” column to the table. Then, have students assign the favorite foods they mentioned, or other examples, by adding words or drawings to each category of the class chart.
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Ask, Where is your flavor detector? Hopefully students will point to the tongue. Ask, Did you know your tongue is connected to the brain? Discuss how the brain receives and manages “taste” information (receptors in the tongue detect different chemicals and communicate with the brain; the brain interprets the messages as flavors).
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Ask, Have you ever really looked at your tongue? Give each student a mirror with which to exam his/her tongue. Ask, Do you notice little bumps on your tongue? Explain that these bumps contain taste buds, which detect the flavors of anything we place in our mouths. Write the number 10,000 on the board, and tell students that there are at least 10,000 taste buds on a typical person’s tongue!
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Have each student draw and color his/her life-sized tongue in his/her notebook.
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Tell students that they will be conducting an investigation using their sense of taste. Emphasize that scientists normally do not taste materials, but that, in this case, tasting is necessary and completely safe.
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Give each student a disposable plate (paper or foam) and a set of small portion cups that are pre-numbered (1 through 4) that contain the mystery substances. Tell students that they should test only the substances on their own plates and should not share with any other student.
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Give every student one cotton swab. Demonstrate how to dip the tip of a swab into a container and touch your tongue with the sample. Instruct students to test container 1. Ask, How did the substance taste?
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Instruct students to use the other end of the swab to test container 2. Ask, How did this substance taste? Encourage students to pair-share their observations.
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Give each student a second swab and have them test containers 3 and 4, using one end for each sample. Again have them share the taste with their partners.
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Ask students, How were you able to identify the contents of each container? What was the taste of the sample in container one? How about number two, etc.? Which part of the body allowed you to recognize the different tastes? [The brain]
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Remind students that taste buds in the bumps on our tongues collect information about the flavors of food, and then send that information to the brain. Add a piece of yarn to connect the tongue to the brain on the classroom human body diagram.
Part 2
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Give each student a plastic spoon and a clean, clear plastic cup half full of water. Tell the class that they will experiment with their senses of taste.
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Ask, What does lemon juice taste like without sugar? [Sour] Why do people add sugar to lemon juice? [To make it taste sweet] Do you like things very sweet or only slightly sweet? Give students time to respond. Then, direct each student to put one spoonful of lemon juice and one spoonful of sugar into his or her cup and stir gently. Be sure students understand that they should use only one spoon for each container.
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Prompt students to take a small sip. Ask, Was your lemonade sweet enough? Does the lemonade still taste sour? What other things have you tasted that were sweet and sour?
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Instruct students to add another spoonful of sugar to their cups, stir gently and taste again. Ask, Did you like the lemonade more or less after adding the second spoonful of sugar? Explain that preferences (likes and dislikes) are shaped by information in the brain, and differ from one person to the next. Also mention that preferences can change over time.
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Have students write a sentence in their notebooks about what they have learned.
Extensions
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If students have questions about the taste, “bitter,” allow them to sample small pieces of unsweetened(bitter) dark chocolate.
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Have students identify foods or drinks that have a combination of tastes. [For example, sweet and sour sauce, sweet and salty candy, or bittersweet chocolate.] Conduct a tasting session with some of these items.
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Take a class survey of favorite foods and record the answers on a chart. Determine which tastes are most and least popular. Make a class graph of the numbers of students who select each taste.
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Explore the connection between taste and smell by having students conduct a taste test of lemonade while pinching their noses.
Recommended Resources
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Cole, Joann. The Magic School Bus Explores the Senses. (2001) Scholastic, Inc., ISBN: 9780590446983
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Cuda-Kroen, Gretchen. “Baby’s Palette And Food Memories Shaped Before Birth.” NPR. Web. 02 Feb 2015. http://www.npr.org/2011/08/08/139033757/babys-palate-and-food-memories-shaped-before-birth
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Rissman, Rebecca. Tasting (The Five Senses). (2010) Heinemann Educational Books. ISBN: 9781432936891
Related Content
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Making Sense!
ReadingMaking Sense! is a colorful, engaging picture/storybook that introduces students to the brain and the five senses as they solve mystery picture puzzles.
Funding
National Institutes of Health: Blueprint for Neuroscience Education, National Institute on Drug Abuse and Science Education Partnership Award program, Office of the Director, Division of Program Coordination, Planning and Strategic Initiatives, Office of Research Infrastructure Programs.
The Learning Brain: Interactive Inquiry for Teachers and Students
Grant Number: RD25DA033006