Taste, Smell, Touch

Rocenetta Jacobs               Roswell B. Mason Elementary School
                               4217 West 18th Street
                               Chicago IL 60623
                               (773) 534-1530

Objective:

     This lesson is designed for grades third through sixth, although it can be 
modified for any grade level.  The objective is to compare and describe objects 
by using the senses of touch, smell, and taste, and to demonstrate more clearly 
how a single sense works by eliminating one of the other senses. 

Materials Needed:

1 meter measuring stick
1 spray bottle of perfume (any brand)
dixie cups (number will vary depending upon class size)
hot water (not scalding)
ice cold water
vanilla extract
lemons or lemon juice (your choice)
plain water
vinegar
tonic water
Soda - Coke and Pepsi
Various fruits of different textures and flavors
Assorted items of varying textures i.e.; felt, fabric, carpet samples, piece of 
 marble, sandpaper, leather, wood, etc.
straight pins or tweezers (depending upon age of children)

     ACTIVITY #1: TOUCH

Strategy: Students will experience different sensations when the skin is
stimulated by touch, pressure, heat, and cold. 

To demonstrate the sensation of Pressure: Have the students place their index 
fingers together and push.  The fingers will create a sense of pressure on each 
other.

To demonstrate the sensation of Heat and Cold: The students will place their 
fingers into two cups of water simultaneously, one cup of ice water and one cup 
of hot water.  Observe the sensation that your body temperature will adjust to 
the temperature of the water after a few moments. 

To demonstrate the sensation of Touch:  Place items of varying textures into a 
bag or mystery box.  Have students close their eyes (or blindfold them), and 
have them pick an item.  They are to describe the item and attempt to identify 
it based only on the way it feels. 

To demonstrate how well the touch sensors are able to distinguish two or more 
closely spaced objects:  Cut three pieces of cardboard and push one straight pin 
into a piece; two into another; and three into a third.  Have students gently 
touch each pin with a finger and try to determine the number of pins, one, two 
or three.  Each child should be blindfolded or have eyes closed.  If children 
are too young you may substitute with the tweezers. 

     ACTIVITY #2: SMELL

STRATEGY: Students will investigate both the acuity of the sensation of 
smell by sniffing various items, and how scents diffuse through air. 

The instructor will place four bottles covered and labeled A, B, C, D on a 
table.  Each bottle will contain one of the following liquids: vinegar, vanilla 
flavoring, lemon juice, plain water.  The students will sniff each bottle and 
write down what they think the contents are.  After all students have sniffed 
the bottles the instructor can tabulate the guesses on the chalkboard or on a 
wall chart.  The accuracy of the student's guesses will depend upon previous 
experience.  Once they have smelled a scent they will never forget it.  If they 
have not smelled these scents they will have difficulty identifying the liquids. 

To demonstrate the Rate of Diffusion of a scent:  The instructor will hold a 
spray bottle of cologne and line up 4 students 2 meters from each other and on 
a straight line with the teacher as one point.  The first student will be 2 
meters from the teacher.  The teacher will spray cologne vertically into the 
air (not in the direction of the students).  Simultaneously, a helper will 
start timing using a watch with a second hand.  When each student on the line 
first smells the cologne, they will call out; a recorder will record the time at 
which this happens.  The data will be plotted as a graph of distance travelled 
by the cologne (Y-axis) versus time (X-axis). The rate of diffusion is the 
distance travelled/time.  It can be calculated individually for each person 
(point) on the line and these values averaged.  Also the diffusion rate is the 
slope of the line on the graph. 
   The equation:  Rate of diffusion = Distance (meters)/ Time (seconds). 

     ACTIVITY #3: TASTE

STRATEGY: Students will experience the sensation of taste.  The students
will discover that the sense of taste and smell are integrated. 

To demonstrate the sense of taste.  The instructor will place fruit of various 
flavors into cups.  Each student will be blindfolded and a partner will place a 
piece of fruit into his/her mouth.  The student should pinch his/her nose closed 
for the first piece and try to identify the fruit.  The partner should follow 
with the same fruit but the subject's nose should be open.  Instruct the student 
to try to identify the fruit based solely upon taste.  In other words don't 
identify a banana because you know how it feels in your mouth.  It should be 
easier for students to identify fruits with their noses open. 

The Coke and Pepsi Taste Test.  The question is can you actually tell the 
difference between Coke and Pepsi?  The instructor will place Coke 
and Pepsi into cups and label them A and B.  The students will taste each and 
try to guess which is which.  The results should be tallied and checked for 
accuracy.  This exercise would work well with two liter bottles that have had 
the labels removed and are marked A and B corresponding with the cups.  Math may 
also be integrated by using percentages. Create a circle graph and indicate the 
percentage of students that guessed A was Pepsi or B was Coke.  This can then 
be extended to calculate the percentage of correct guesses.  

To demonstrate the sensations of bitter, sweet, sour, and salty.  The instructor 
should label cups A, B, C and D.  The cups will contain tonic water, 
representing bitter; fruit juice, representing sweet; lemon juice, representing 
sour; and salt water, representing salty.  The students will taste each solution 
and try to identify the location on their tongue where the taste of each 
solution was most prominent.  The students should drink plain water in between 
tastings. 

Performance Assessment:

     1.  Provide a picture of a tongue.  The student will accurately 
         identify the location of taste buds and the taste they represent 
         bitter, sweet, sour, and salt.

     2.  Answer the following questions:

     A.  If you place a drop of honey or a sugar cube into your mouth, which 
         food will stimulate the sweet taste buds first?

     B.  When the fruit was tasted with your nose closed it was more difficult 
         to identify.  Why?

     C.  When you have a cold your sense of smell is lost.  Explain why?

     D.  When the human sense of smell is compared to that of animals whose 
         sense of smell is better?

     E.  Which sensory receptors are stimulated by heat, touch, sight, and 
         smell? 

     F.  Was it more difficult to identify objects by touch only than it would 
         have been using touch and sight together?  Why?