1.2 How Can Models Help Me Understand Odors?

How Many Different Odors Can You Smell?

When you eat an orange, you usually can smell the orange odor. Every time your nose is near an orange, you smell a similar odor. You will not smell that odor when you smell the air around other fruits. Bananas, apples, lemons, and kiwis all have different odors. Your nose can tell the difference. In fact, people's noses can detect many thousands of different odors.

Look back at the list of odors you made. Choose one odor from your list. You can choose an odor you like or one that you do not like. Draw the source of the odor in bottom right side of your paper of the diagram. Then, in the circle at the top of your paper, draw a model of what you would see if you could look at a tiny spot between the source and your nose in the bottom left side of your paper. Imagine that you are using a special instrument that lets you see the smallest parts of the odor. Be sure to label the parts of your model.

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Sometimes the model you imagine in your head is difficult to represent with a drawing. Sometimes what you imagine is difficult to explain with words. Often, it is easier to use words and drawings to explain phenomena. In this unit, you will draw models and write about them. As you study in science, you will sometimes change your models. Scientists do this, too. When you learn new information, you sometimes need to revise your old model.

Why Would Someone Change a Model?

A model that helps you describe what you know about odors today might not help you explain what you learn about odors later in this unit. Your model might stay the same or it might change as you learn new information. It is okay if you change your model. It is okay if you keep the same model. It is important to make sure that the model you use can help you explain the different phenomena you experience.

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Here is an example of using different models. If you asked a scientist to describe the continents on Earth, that person could use a globe or a map.

A map and a globe can both be good models. If you had to explain why the temperature in Alaska is cold for most of the year, a globe would be more helpful than a flat map. Different models work better for different purposes.

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How Are All Odors Similar?

In class, you drew a model of what makes up an odor if you could actually see the odor. In this reading, you drew a model of a different odor. Wherever you are—in a classroom, outside, on a bus, at home—you can smell odors because they become part of the air. All odors that humans smell have that in common—they all move as part of the air.

How Are Odors Different?

Even though the thousands of odors people can smell go from a source into the air to their noses, each odor is very different. Think about that. What makes an odor that you like different from an odor you do not like? Write your ideas about why you think various odors are different from each other.