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## Cold air is Dense

### Introduction:

we wish to set up a learning case in which students will discover, with the examination and manipulation of real data from a herbal environment, that:air has mass and density, andcold air is denser than warmth air. These insights space absolutely an essential to knowledge virtually everything around weather and climate. Until a student has actually his or she mind firmly roughly these two concepts, the or she is not all set to understand exactly how storms work, not prepared to know why the prevailing winds blow the method they do, not prepared to understand why deserts take place where lock do.Although these two principles are an essential underpinnings of basically every physical procedure in the atmosphere, they space not intuition obvious--in fact, they room counter-intuitive. The student looks about at the wait skeptically-- if there are so numerous molecules in that air, why can"t we see them? If air has weight, why doesn"t it register on a scale? On hot summer nights, the air feels oppressive, heavy--don"t phone call me that hot August wait is low density "Air has mass", "air has actually density", and also "cold air is dense" space the kinds of statements that students often tend to memorize and also parrot back, there is no actually altering their world-view, because these declaration don"t fit through their day-to-day endure of real-life air. Because an understanding of the relationship between density and temperature of air is basic to so many natural processes, however is counter-intuitive, it is a good investment of student and also instructor time to construct this understanding upwards from a solid communication in the monitoring of genuine data.

### Insights/Curriculum Highlights:

Air is do of molecules, and therefore has mass. Barometric pressure is a measure up of how much mass of air, i.e. How many air molecules, exist above the point of measurement, all the method up to the peak of the atmosphere. Therefore, barometric pressure decreases through elevation. Any given volume the air has actually density. The thickness of air deserve to vary from place to place and also from time come time.The distinction in barometric pressure in between observation web page at various elevations is a measure of the thickness of air in a tower of air in between those two elevations.Cold wait is denser than warm air.

### Thinking skills / Pedagogical Highlights:

Making a connection between laboratory range observations and also atmosphere-scale data sets. Drawing on hand-operated observations to define an facet of a organic system. Thinking around a phenomenon (density that air) that is invisible. Imagining limits or limits, and thinking about phenomena in ~ those boundaries (a shaft of air, a package of air)Linking nature that space detectable to the human being senses (e.g. Wait temperature) with molecular scale phenomena (molecules per volume that air).Linking nature that are measurable at the macroscopic scale (e.g. Barometric pressure) to molecular range phenomena (number of molecules). Structure a chain of thinking from cause to effect.Building a chain of reasoning from observation to interpretation. Using time series graphs; comparing how different parameters vary with time. Recognizing the a measurable home varies with time (barometric pressure rises and falls together weather solution pass) and likewise through space (barometric pressure decreases with boosting elevation).Recognizing covariance: 2 properties varying in the very same direction under the affect of the exact same circumstances (barometric push at the open up Lowland website covaries v that at the Ridgetop site). Using a scatterplot; thinking about two or 3 data parameters simultaneously.