Chemical Education Today
Commentary
What Is Your Mental Picture of Ordinary Air? by Richard W. Ramette and Dale K. Haworth
One day in the 1970s we wondered how beginning chemistry and art history students might differ in how they answered the question, “What is your mental picture of ordinary air?” Both groups were primarily freshmen, most of whom had taken high school chemistry. As readers will observe when reading the student responses in the boxes, the question has as many different answers as the number of responding students. No doubt the style of the responses are skewed according to the field of the interrogating teacher. We make no profound interpretations, but it’s refreshing to enjoy free expressions of student opinion, especially in a discipline (chemistry) that typically expects unsurprising answers to structured quizzes. Readers of this Journal may enjoy trying this with their own students. Many terms could be substituted for “ordinary air”, such as ordinary water, an atom, the solar system, etc. Or, try this: “What do you think distinguishes chemistry from other sciences?” As a teaching tool, selected responses could be shared for class discussion. Students would benefit from comparing and criticizing diverse statements, and teachers would benefit by learning some common misconceptions. Follow up activities could include a contest among groups of, say, five students to compose the most accurate but also
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most interesting answer to the question. The teacher might also predict that the same question will appear on the final exam. Only a few selections are presented here, ranging from scientifically accurate to those with serious misconceptions; many are just fun to read. Conclusions We found this to be an interesting exercise. It was surprising that many students consider hydrogen an important component of air. A worthwhile class discussion could explore the questions, “Why is there so little hydrogen in ordinary air given that it is the most common element in the Universe?” and “Why are we very glad that hydrogen is not a major component of air?” Richard W. Ramette is an emeritus member of the Department of Chemistry, Carleton College; 765 W Fountain Creek Drive, Green Valley, AZ 85614;
[email protected]. Dale K. Haworth is an emeritus member of the Art History Department, Carleton College; 3101 Old Pecos Trail # 610, Santa Fe, NM 87505;
[email protected].
“What Is Your Mental Picture of Ordinary Air?” Responses from Chemistry Students
Air is composed of a lot of molecules, which are composed of even more atoms which are constantly all moving and spinning around. It’s colorless and odorless, a gas—something as basic as this I’m not even qualified to write about, that’s how bad that I am. I’m afraid that most of the time I tend to ignore the very existence of air (and there’s ingratitude for you!); but now that you ask, here’s what I imagine air to be on a molecular level: Lots of little nitrogen and oxygen molecules zipping back and forth, running into and flowing around objects—mixed with various other elements, all moving in all directions at great speeds.
My mental picture of ordinary air is that it is made of elements, O, H, N, C being the main elements. All these elements are necessary for life to exist. There are millions of these elements in compounds. A substance composed of oxygen, nitrogen, and hydrogen in a gaseous state. My mental picture of ordinary air is a conglomeration of oxygen and dust along with various amounts of other gases such as hydrogen. I suppose I also imagine little molecules and atoms floating around out there.
I think of ordinary air in terms of a block. A block of air can have any shape be it of a bottle or a donut shape with the earth as a center—the donut becoming less dense the further you go from the earth.
Clean air is just a variety of different molecules floating around in currents with nothing in between. Its state is that of a gas. It is not an element, nor is it a compound. It’s just a mixture of such elements as oxygen, hydrogen, nitrogen, etc. Ordinary air is something quite different, however, for many of its molecules consist of carbon monoxide, sulfur dioxide and other things that will kill you in no time.
An infinitely large number of small particles buzzing around and irritating my lungs. Carbon, hydrogen, nitrogen, oxygen and helium are all mixed into one noxious blend.
continued, p 836
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Chemical Education Today
Commentary
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“What Is Your Mental Picture of Ordinary Air?” Responses from Chemistry Students (continued from p 834)
Chemically I think of air as being a number of elements— hydrogen, oxygen, etc. combined together in a gaseous state. I don’t really understand gases but I would suppose that the atoms within them are spaced much farther apart then in solids or liquids.
Well, it’s a chemical compound of a few basic elements—oxygen, hydrogen, nitrogen and carbon, I think. So one molecule of air would have a molecular weight of the combined atomic weights of these in their proportions in the compound. It is a colorless gas.
Air is a mixture of numerous gases which extend through the entire atmosphere and even in the terrasphere. It is a combination of gases such as hydrogen, which is the greatest in amount, oxygen, carbon dioxide, helium and many inert gases in trace amounts.
A constant collision of various atoms bombarding me.
Air is unimaginable except as intervening space, known rationally to be a substance and not nothingness. Bulbous bulging globules, some big and some small, bumping and careening off each other in a rhythmic degree according to the speed of the ebb and flow of timeless life. Air wonderful air! How sweetly doth the gentle breath of spring lift up my soul! Beyond the poetry of earth and sky, air is, as I remember, a mixture of gases of various elements and compounds, which surrounds the earth and forms the layer of the atmosphere closest to the earth. Air is a mixture of gases (I can’t recall the percentages of the elements which are present). Air is the basic element of life. Actually I have no mental picture because I’m really not sure what it is.
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A collection of particles from ping-pong to soccer ball size floating around either singly or in combinations, CO2, H2O, O2 and microorganisms. Although I do have mental images for some things which I can’t see, for air I have absolutely none. I see air as lots of little particles floating around and bumping into each other. If you look closely at all the particles (which remind me of dust particles glinting in the sunlight) many are double globes shoved together to look like oranges with a piece cut straight off. Each of these particles has its own color for example hydrogen is blue and oxygen purple but when the light goes through it absorbs all the color so you only see clearness. Otherwise it would be like a pointilist art painting and everyone would be so awed by the colors they would just keep staring at all of the forever moving darting glorious specks of elements and light.
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“What Is Your Mental Picture of Ordinary Air?” Responses from Art History Students
Air is one of the most amazing and mysterious things in all creation. One cannot actually swear that air exists. Yet when I dream, and often when I am walking I somehow understand the properties of air and attach physical qualities to it. In dreams, air becomes a bubbly-structured thing, almost like enlarged models of atoms and molecules suspended in space. They are transparent and engulf the person. Air, contrary to popular (scientific) opinion (fact?), and unlike water, does not take the shape of its container. That is to say, it does not fill the container but just sits comfortably inside. But air is quite practical, and lazy, and goes where it is needed only when it is needed. Take this room for example. There is no air way up in the corner. If I were to look at air, I would see nothing, just an empty void. If I were to see air, I would see transparent billowy figures silently floating and gliding about the void. There would be colors, but not deep ones, only soft pastels in shades of orange, pink, and yellow rather than blues and greens. The air would not be totally taken up by the figures; there would always be void areas. These areas would change as the figures moved. My mental picture of air is an uncountable number of diatomic molecules moving about in random directions bumping into each other. I see ordinary air as a thin; invisible mist that can become puffy and thicker, that moves and floats in circular patterns, that rolls from room to room when doors are opened.
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When I think of air, I see clumps of molecules. The clumps are spread far apart from each other and are ever-moving. Air is not composed of uniform substances. Many different kinds of gases and solids make up air. Air looks clear to us, but can be in reality very dirty. Air is the space between all the objects one can see, feel or perceive in some other way around him. It is the colorless matter that separates the colors we see, the textureless space between textures we feel, the odorless space between odors we smell. Air is very light and very fluid. It is also clear, clean, and fresh. Air moves very fast and tries to always be everywhere at once. Air knows all, sees all, and feels all. I see air as being blue, dotted, and swirly, like dust storms. Kind of like Van Gogh’s Starry Starry Night only lighter blue swirls with multicolored dots in them. I don’t know how to explain it, but I can see it. I have to close my eyes to see it. My mind carries no visual mental picture of ordinary air. I know of its existence, its chemical structure, but it is really nothing to me. It is when air moves, that I feel a force against me, that I gain a concept of what air is. My mental picture of air comes from the feelings that I get as I feel air rushing past me as wind. Air is what surrounds us. It’s necessary for human life. While it is transparent and basically featureless it also has its moods. Sometimes in the morning it seems hazy, heavy and solemn. On a hot summer day it appears to be full of gleaming sunlight.
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