Smelly Penguins

Introduction

While humans tend to rely on their vision, animals depend much more on other senses such as hearing and smell for their survival.  For example,  they often use unique calls (sounds) to communicate danger, dinner time, approval, and disapproval. They also use their sense of smell to interpret dangers, find food, and attract the opposite sex.  Sometimes they even use smells  to recognize each other in a crowd. For example, penguins are often born in nesting sites than contain thousands of penguins . With this big of group, the noise from the crying babies can be deafening. When mom leaves the nest to go out fishing for dinner, the only way that they can recognize each other when she returns is by their own unique smell.  

But what about us humans? Many scientists think that we have lost some of our ability to hear and smell as it has become less and less necessary for our survival. What do you think?  If we put your mom or dad in a room with a thousand parents and then blindfolded everyone, would you be able to recognize them just by the sound of their voice?  Or better yet, if we didn't let them talk either, could you correctly identify them just by smelling them?

Materials:

Scented liquids              Cotton Balls          Film Canisters           Paper and pencil

Exploration:

In the activity you will pretend that you are a baby penguin and your goal is to find your momma using only your sense of smell. 

Procedure:

1. Divide the class into two groups and let one group be momma penguins and the other group be baby penguins.   Place all of the lids in one area and all of the canisters in another.

2. Have each baby penguin take the  top of a film canister that has been treated with a scent and each  momma penguin take the bottom of canister that has treated in the same way .

3. Have each penguin smell their own scent and try to describe it to themselves.

4. Have the penguins waddle around and smell each other. As they do so they should write down a word or two that describes each smell (peppermint). The penguins should not talk during this time (since penguins can't talk).  Their goal should be to find their momma or baby but even after doing so they should still make sure to smell all of the penguin mommas or babies.

5. After this is completed, each pair should agree on a term to describe their smell and then each group should share these terms with the rest of the class.  

Guiding Questions:

1. Did you find it difficult or easy to find your momma (or baby)? Explain why you think this was so.

2. Was anyone unsure of a scent or did scents overlap?

3.  Do you think we have a better sense of smell than most animals? Explain your thinking.

4.  Do you think that we could learn how to smell and hear better if we practiced?

5.  What was favorite smell today? Which was your least favorite?

Explanation:

Concept discussion:

As humans we have the ability to detect a few thousand different smells. With a few million smell receptors in each of our nostrils we have a decent sense of smell.  But compared to many animals such as dogs and deer  our sense of smell isn't nearly as good. Many animals also use their sense of smell to communicate with each other more than we do. For example, ants lay down an odor trail between a food source and their nest so that others can find their way.  It is likely  that we have lost some of our capacity to smell as this sense has become less necessary for our survival in the world.  There are a few things you can do to improve your sense of smell. For one thing, by sniffing like a dog you bring more air into your nose so that more of your smell receptors are stimulated. You can also train yourself to be a better smeller by practicing. For example, people who develop and test perfumes learn how to tell the subtle differences between hundreds of fragrances (scents). 

In addition to their superior sense of smell, animals have other senses that can exceed those of humans. As examples, both dogs and deer have a much greater range of hearing than humans and eagles and hawks have much better vision. For these animals, their keen senses are  necessary for their survival.

Objectives:

The students will describe and compare characteristics of different animals such as coloration that enhance their survival.  

Teacher Notes:

For this activity, you need a film canister and lid for each pair of students in your class. You also need different scents for each of those pairs. Place a small amount of the scent onto a cotton ball and then turn the canister upside down in  order to let the scent form on the lid of the canister. Shake the container well to make sure enough of the scent gets on the lid. Suggestions for scents include: perfume, mouthwash, aftershave, flavorings like peppermint, banana, vanilla, anise, and lemon, vinegar, syrup and others. Just be careful not to include anything like ammonia that could be harmful.  If you can't find enough scents, you can do two or three pairs of each scent. Extra film canisters can be found at any store that develops film and they will gladly donate to teachers.