Lesson Plan

Pathways to Discovery - "Scent"sations!

An ant crawls over a caterpillar to get at flower nectar
Find out how one ant can lead another to something like a food source
NPS Photo / Robbie Hannawacker

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Subject:
Biology: Animals
Duration:
20 minutes
National/State Standards:
Alaska State Standards
Science: A12, 14, 15; B1, 2, 3; D1, 2;

Overview

Use America's largest national park as a pathway to discovery!

In this lesson, students learn how insects find one another using their sense of smell through smelling activity.


Objective(s)

Using discovery, activities and observation, students will better understand the role of little creatures as they relate to their habitat and other living things.

Background

Use an area that is fairly large and flat. Ask the students, “How do animals find one another in the forest?” (Mostly through the sense of smell.) Many animals have glands located on their legs or their lower body. These glands produce odors which are left on the ground. These odors help one animal track another. Tell the students that they are going to take part in an activity that shows how they can find a partner using their sense of smell.

Materials

Pairs of small closed containers with scents on cotton balls (cinnamon, peppermint, lilac, etc.), blindfolds

Procedure

Ask the students if they’ve ever seen a line of ants walking along the ground. If an ant leaves the colony after the line has departed, how does it find the line of ants? (By the scent the ants leave behind). Where does this scent come from? (A gland on the ant’s abdomen). As the ants walk, they occasionally drag their abdomen on the ground, thus releasing the odor. Other animals release a chemical, called a pheromone, into the air to attract their mate.  

  • Have the students form a circle. Take out the film containers. Inside each one is some cotton that has been soaked in some scent (peppermint, cinnamon, lilac, etc.) Choose up to half the group to go inside the circle. The other half forms the boundary. First, as an example, blindfold one student and let that student smell the odor in the container. Have six unblindfolded students open their containers and see if the one with the blindfold can find that matching scent.  

  • Next blindfold half the insiders and give each a film container. These will identify their partners through their sense of smell. Give the other insiders a duplicate scent container. These will be found by their scent.  

  • The unblindfolded students position themselves in one place. The blindfolded students try to find who has the same scent. When successful, the pair joins the outer circle. • When all partners have been found, pass the film containers around and try to identify the scents.
Note: Because of a human’s relatively poor sense of smell (when compared to other animals), it may be difficult for students to identify the scents that are being passed around. Use this as an example of the fantastic sense of smell that most animals have. Humans are also subject to suffer from olfactory fatigue, a condition where the nose stops detecting the odor even though it is still present. This is helpful when the odor is unpleasant.

Assessment

Ask the students: Would we be able to track an ant without seeing it? How about a prey species, such as a hare or moose? (Probably not, our sense of smell isn’t sensitive enough.) Was it difficult to identify the scent? Why or why not? What are some other ways little creatures might be able to recognize prospective mates or other members of their kind? (sound, light)

Additional Resources

This lesson is part of our "Pathways to Discovery" unit. The individual lessons can be done individually or as a larger unit of learning. They encourage the development of a student’s awareness and appreciation of the natural world and people’s relationship and role as a part of that natural world.

The lessons are a series of shorter activities that have been blended together under a specific theme with the intent that the activities will be coordinated with units in the existing school curriculum and texts. The materials are organized by grade level, but can actually be adapted for use at any grade level. Check out the full Pathways to Discovery unit of lessons, as well as links to other stand-alone lessons like this one.