In my five senses unit, I dedicate two lessons for each sense. The first lesson is an inquiry lesson in which the students engage in an experiment to trigger questioning and build background knowledge. The second lesson shares more information about that specific sense to help expand the students' understanding.
To begin the lesson, I take a piece of chart paper and I ask the students, What do you know about your sense of taste? I record the responses on the paper. I don't worry if the students do not have a lot of information to share. This will expand and grow after their exploration and learning about this sense.
For this experiment, you will need the My Tongue Map recording sheet, included as a PDF with this lesson (one copy per student) and the following supplies:
Liquids placed in small portion or Dixie Cups. I do one set of cups per student. I only place the first cup at their seats so they do not become confused as to which cup they should be using. We dispose of each cup after each test and I pass out the next cup. See picture of set-up.
Salty Taste: salt water (mix table salt with water until salty to taste)
Sweet Taste: sugar water (mix sugar with water until sweet to taste)
Sour Taste: lemon juice
Bitter Taste: tonic water
Four cotton swabs per student
I pass out the tongue map and have them write their name on top. They also have the Salty Taste cup at their seats.
I tell the students, We are going to explore how different parts of our tongue taste different tastes. I want you to put your hands in your lap and not touch anything. Just watch what I am doing. When I say to, you will dip the cotton swab in the liquid in the cup. I want you to touch the cotton swab to the very tip of your tongue just like this. Now you do it. Can you taste anything? No? Now dip it in the cup again and move the cotton swab a little to the side of where you touched it before and try again. Can you taste something now? The students should be able to taste the salty solution.
This taste is salty. We are going to mark on on the diagram where we were able to taste the salty taste. Scientists use diagrams like this to help them organize information. I want you to take a blue crayon and color in the box next to the word salty (I point to the word on my sheet to show them where to color). Now, find the spots on your tongue map that have the number 2. That is where our tongue was able to taste the salty taste. Color those spaces blue. I circulate around the room to make sure they are coloring the correct spaces.
I collect those cups in the garbage and pass out the sweet taste. It may help to drink a bit of water in between tests. We repeat the test again. I have them then try the taste on the tip of their tongue. They should be able to taste the sweet taste right away. We color in the map using a different color this time. We continue with sour (area 3 on the tongue map) and bitter (area 4).
It was really a lot of fun to watch the students trying the tastes on the different areas of their tongue. The video shows the students trying the bitter taste. Watch the change in their expressions as they hit the area of the tongue that detects bitter: Mapping It Out
We clean up their work area, but leave the tongue map in front of them and move on to the discussion portion of the lesson.
The discussion after the experiment is important to help the students "think like scientists".
I ask the following questions:
Can you taste every taste in every area of your tongue?
Which taste did you like the best?
Some medicines and poisonous foods have a bitter taste. Why would it be important to know that something tastes bitter? How could being able to taste bitter tastes help an animal survive? (Animals would be able to detect poisonous plants/berries).
Cows have more than twice the number of taste buds on their tongues that we do. This means that they have a much better sense of taste and can taste things that we can't. How could this help the cow survive (ability to taste grasses that are poisonous).
We used our sense of taste to do this experiment. Would any other sense help us to do this experiment? Sometime we use our sense together, sometimes we use them by themselves.
We used our sense of taste to make a scientific drawing of a tongue. This drawing is called a scientific diagram. Why might scientists make diagrams?
Scientists might need to use their sense of taste sometimes. Our sense of taste is an important observational tool. For example, some scientists taste things to learn more about them. A geologist is someone who studies rocks. Geologists sometimes use their sense of taste to help them figure out where a rock came from. They might lick a rock to see if it tastes salty. A salty taste would tell the geologist that the rock came from the ocean.
What are some things you can tell your family tonight about we learned about our taste today?
After our discussion, we revisit the chart paper. I ask the students if there is anything else they want to add to the chart. I record the answers on the chart. I save the paper for our next lesson in which they will further explore their sense of taste.