EXPERIMENT OBJECTIVES AND CONTENT

In this activity, students are initiated into how thefive human senses–taste, smell, sight, touch, andhearing–are useful and complement each other.

ESSENTIAL KNOWLEDGE

Matter:• Organization of living things: anatomy

of animals, senses

Systems and interaction:• Interaction between humans

and their environment

Techniques and instrumentation:• Use of simple measuring instruments

Appropriate language:• Terminology related to an understanding

of living things• Drawings, sketches

SUGGESTED MATERIALS

Scientific equipment:• Anatomical chart• Droppers• Food thermometers

Perishable non-scientific materials:• Water• Solid or liquid foods• Food coloring• Suckers (lollipops)• Potpourris

Household materials:• Aprons• Head bands• Nose clip• Ear plugs• Plastic glasses and plates• Mixing bowls and spoons• Paper towels• Cotton swabs• Potato masher

School supplies:• Pencils

CONTEXT: SITUATIONAL PROBLEM OR RESEARCH QUESTION

Imagine that it is snack time and that you open your lunch box only to find strange foods.Their smells, colors and textures are differentfrom the food you usually eat. What would thatdo to your appetite? Do you think your snack willtaste like it usually does or will it taste different?What senses do you use to enjoy your snack?

ACTIVITY 5

WHAT SENSES PLAY

A ROLE IN THE

ENJOYMENT OF FOOD?

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BE ATTENTIVE TO FOOD ALLERGIES

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SUGGESTED PREPARATORY ACTIVITIES (INTRODUCTION)

The teacher suggests an activity on discoveringthe senses. Different stimuli are presented to thestudents: a potpourri, a lead pencil and a lollipop.The teacher asks the students to name the sensethey use to identify each item. With the help of a table drawn on the board, the students realizethat more than one sense can be used to recognizea single object. What about the foods and disheswe eat?

INITIAL IDEAS AND HYPOTHESES

Here are a few examples of hypotheses the studentsmight formulate based on their initial ideas:

Example 1I predict that the sense of sight plays a role in whetherI like a food or not. I predict this because the otherday my mother bought green pasta to make lasagnaand I couldn’t eat it until I closed my eyes.

Example 2I predict that if I pinch my nose I can swallow liquids I don’t like. I predict this because when I have to takecough syrup, my dad tells me to pinch my nose.

Example 3I predict that a food is tasted primarily on the tip ofthe tongue. I predict this because my grandmotheralways puts her finger on the tip of her tongue tocheck the flavor of her spaghetti sauce.

Example 4I predict that sound plays a role in whether I enjoya food or not. I predict this because sometimeswhen I hear someone eating potato chips, I feel likeeating them too.

Example 5I predict that the texture of a food affects whether I like it or not. I predict this because I hate anythingthat feels like gelatin, even if it tastes like chocolate.

WORK PLAN AND EXPERIMENTATION

Here are a few examples of experiments the studentscan carry out to verify their hypotheses:

Example ATeams of students pair up and change the color oftheir food by adding food coloring. Each team usesdifferent foods from the other team. The studentsexamine the transformed substance or food and tryto identify it. They also indicate in their experimentworkbooks whether they enjoy eating the foodunder normal circumstances. Then everyone tastesthe foods prepared by the other team and indicateson a chart how much they enjoyed it.

Example BWhile plugging their noses with a nose plug, thestudents taste different foods such as herbed rice,strawberry yogurt, or applesauce. Each containershould have the same amount of food. Then theytaste the foods a second time with their nosesunplugged. Do they observe a difference? Are thetastes more pronounced?

RECORD ALL YOUR IDEAS AND OBSERVATIONS

IN YOUR EXPERIMENT WORKBOOK.

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Example CThe students draw a tongue in their experimentworkbook and identify the sections of the tonguethey believe are responsible for the different tastes(sweet, salt, bitter, and sour). By placing foods onspecific areas of the tongue with a dropper or cottonswab, the students associate the parts of the tonguewith different tastes. Note: The students could alsotest the importance of saliva in determining thetastes of foods or dishes by drying out their tongueand seeing if there is a difference.

Example DThe students select foods or dishes that make noisewhen they are consumed: apples, carrots, potatochips or celery. With their back turned to the personeating the samples, the other members of the teamtry to identify the food or dish. The students shouldalso assess whether or not hearing the soundmakes them want to taste it.

Example EThe students take cookies, cereal and cooked oatmeal.They crush the cookies and cereal, add water to makethem into a puree. In this way they obtain threesubstances with a similar texture. They pour smallamounts into glasses and identify them. Then the teamcarries out a taste test to evaluate whether they stilllike the foods as much as in their original form.

Note: the temperature of a food or dish can also affectone’s perception of its taste. The students could alsoexperiment with this factor.

EXPERIMENTAL FACTORSTo ensure scientific rigor, the students should evaluatethe experimental factors that might influence theexperimental results.

• Hunger level

• Size and amount of samples

• Personal taste

• Having a cold or the flu

• Cleanliness of containers (to avoid mixing smells and tastes)

• Temperature of foods and dishes

DISCUSSION: SUGGESTED INTEGRATION ACTIVITIES (CONSOLIDATION)

The teacher leads a discussion on whether allteams obtained results that confirmed or invalidatedtheir hypothesis. Can the results of the other teamshelp provide an overall understanding of theproblem? A summary table entitled “The Senses I Use to Taste My Food” could be used to pool the results from all teams so that the class canpaint an overall picture of the senses we usewhen we eat. The use of anatomical drawings tovisualize the organs that play a role in sensoryanalysis could be used to complement the activity.

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SUGGESTED ACTIVITIES FOR APPLYING KNOWLEDGE (APPLICATION)

The teacher suggests that students explore theimportance of their senses when they engage in aphysical activity. The class is divided into two:a team of researchers and a team of athletes.The researchers objectively evaluate the sensesused by the athletes when performing a physicalactivity, and the athletes take note of how their senses were useful. The activity ends with discussion between the two groups to synthesizewhat they learned.

SCIENTIFIC CONCEPTUAL CONTENT

What are senses used for?Senses allow us to perceive the world around us.We have five senses: sight, touch, hearing, smell,and taste. Each sense uses a different organ (eyes,skin, ears, nose, and tongue) and tells us somethingabout our environment. These organs transmit thesensory information they gather to the brain via the nervous system. The brain analyzes the data andallows us to better understand the world.

SightSight is the sense humans use most. We see thanksto our eyes and our brain. Light travels into the eyethrough the pupil, and then through the lens, beforean image forms on the retina. The retina capturesthe image and transforms it into nervous signalsthat are interpreted by the brain. Humans can seeperfectly in three dimensions only from the age ofabout six.

Color visionOur eyes only sense three basic colors: green, redand blue. This is the function of cells in the retinacalled cones. The brain, which perceives variations in the intensity of these basic colors, mixes them to create the wide range of colors we experience.

TouchThe skin is the largest organ in the human body,reaching up to two square meters in area. We gathertactile information about our environment, or aboutthe foods we eat, by way of tiny receptors (internaland external) located all over and inside our body.Some parts of our body are more sensitive to touchthan others because they have a higher concentrationof receptors. Examples of such areas are the tips ofour fingers and our tongue.

HearingWe perceive sound thanks to our ears and our brain.However, sound takes a complicated path before itreaches the brain. In a fraction of a second, soundpasses through the eardrum, which vibrates like adrumhead. These vibrations make three tiny bones,called ossicles, move, which in turn vibrate a liquidin the cochlea (a spiral-shaped canal in the innerear). These vibrations are transformed into nervoussignals and sent to the brain.

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SmellThe human nose can distinguish over 10,000 differentsubstances and is one of the first sense to develop.A fetus can detect odors within its mother’s womb,which can affect its preferences after it is born. Mostof the air we breathe goes directly into the throatand lungs; only a small portion comes into contactwith cells in the upper portion of the nose that aresensitive to odors. This structure partially explainswhy the human sense of smell is less developed thanin most other mammals.

TasteThe tongue contains tiny organs called taste budsthat detect four major taste groups: sweet, salt,sour, and bitter. Humans have about 10,000 tastebuds. Of these, 9,000 are on the surface of thetongue. The back of the tongue is sensitive to bitter,the sides react to sour, the tip, where most taste budsare concentrated, perceives sweet, and the sides,between the sweet and sour, detects salt. As we getolder, our taste buds take more time to be replaced,which reduces our ability to distinguish tastes. Ingeneral, a taste bud has a life span of about ten days.

TastingWe use several senses when we taste a food or adish. In fact, our sense of smell is responsible forabout 80% of what we perceive as taste (aromasand fine distinctions), while the sense of touch perceives temperature, texture and spiciness. Hearingdetects the sound made by chewing, and sight stimulates (or not) our appetite. Hence, the fruity flavor of juice is “tasted” by way of the perfumes it emits, and the starchy feel of certain breads is perceived by the sense of touch.

CULTURAL REFERENCES

The pleasure of eatingWhile some animals such as chimpanzees or otterswash their food and use tools to prepare it, humansare the only animals to truly transform their food.From the time of the first civilizations, humans haveadded substances from natural sources to their foodto make them more appetizing and improve theirtaste. These include salt, sugar, herbs and spices.However, humans quickly turned to other types ofsolutions. For example, in Roman times, harmfulsubstances, notably chalk, were added to bread tomake it whiter, which was a sign of wealth.

Today, we constantly change the appearance, shelflife, taste, and even nutritional value of our food.We can now buy purple carrots, cookies that canstay fresh for months, lemon-pie-flavored yogurt,not to mention tomatoes with delayed maturationand softening. We are even trying to produce potatoes that absorb less frying grease to preventcardiovascular diseases.

CultureIn the perfume industry, a person who creates perfumes is called a perfumer, though they aresometimes also called “nez,” which is French for “nose.”

FOR MORE CULTURAL REFERENCES,

VISIT THE ÉCLAIRS DE SCIENCES WEBSITE:

www.eclairsdesciences.qc.ca

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ConceptionMontréal Science Centre

REFERENCES

Les Petits Débrouillards. Le goût et l’odorat. Des expériences faciles et amusantes.“Sciences en poche Les Petits Débrouillards 8-12 ans” collection. Paris: Albin Michel Jeunesse, 2001.

Les Petits Débrouillards. Les surprises du toucher. Des expériences faciles et amusantes.“Sciences en poche Les Petits Débrouillards 8-12 ans” collection. Paris: Albin Michel Jeunesse, 2001.

Parker, Steve. Atlas jeunesse du corps. Paris: Éditions du seuil, 1993.

Chudler, Eric H. “Brain facts and figures.” In Neuroscience for kids. [Website, 2006]http://faculty.washington.edu/chudler/facts.html. Consulted September 24, 2007.

INRA. “Gustation problématiques scientifiques.” In Biochimie de l’olfaction et de la gustation. [Website, 2007]www.jouy.inra.fr/unites/nopa/bog/problsci/gusta/index.htm. Consulted September 25, 2007.

Tesch, Cynthia. “The five senses.” In University of Saskatchewan. [Website, 2003] www.usask.ca/education/ideas/tplan/scilp/senses.htm. Consulted September 25, 2007.

Zamora, Antonio. “Human sense organs.” In Scientific psychic. [Website, 2006] www.scientificpsychic.com/workbook/chapter2.htm. Consulted September 25, 2007.

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process of active discovery general learning process in science and technology (in elementary school)

© 2011 /REV0202EN

My initial ideas:• I share my own ideas.

My hypothesis:• I predict that... I think that because…• I imagine my prototype.• I think it works like this…

My equipment:• I observe and handle the equipment.• How could this equipment be useful to me?• I choose my equipment and my materials.

Carrying out my process:• What will the steps be?• What precautions should I take?

My actions:• I carry out the steps of my protocol.• I note or draw what I observe, what I do and what I discover.

My results:• What is my answer to the problem, question or need?

• Situation problem or

• Discovery question or

• Need to be fulfilled

• Question related to the operation of an object (how does it work?)

My outcome:• Do my results confirm my hypothesis or not? • Are my results similar to those of the other teams?• Can the other teams' results help me to find answers to my problem, my question or my initial need?

• What could I communicate concerning my discoveries?

What I learned:• What do I retain from this activity?• What could I communicate concerning my results or my discoveries?

Context relatedto everyday life

Initial ideasand hypothesis

Planning and carrying out

Outcome

New question?