Experiencing the Scientific Method in a General Education Weather Course

TOM KOVACS is a professor in the Department of Geography and Geology at Eastern Michigan University, Ypsilanti, Michigan.

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An example of the type of maps students are able to interpret after the course. This shows a 72-hour forecast made by numerical weather prediction, with mean sea level pressure (in black), 6-hour precipitation (color scale), and 850 mb temperature (blue below 0°C and red above 0°C).

Provenance: Source: National Weather Service
Reuse: This item is in the public domain and maybe reused freely without restriction.

Weather courses are a popular option to satisfy general education courses in the sciences because of the natural interest students have in the weather, given its impact on our everyday lives. Unfortunately, these courses are often organized in a way similar to most introductory college-level weather textbooks, which do not directly satisfy the students who are mostly interested in weather forecasting and severe weather (Knox and Ackerman, 2005). Often, this course structure also does not adequately satisfy science requirements within university general education programs that typically are focused on learning the scientific method. However, weather forecasting can provide the ideal focus for learning the scientific method. It requires obtaining weather observations, developing empirically based weather relationships from testable hypotheses, and using these relationships and theories to develop forecasts. I have designed and taught a course that aims to provide students real-world experience in applying the scientific method using weather observations in real-time.

Individual thematic units in the course are organized similar to the linear progression in which the scientific method is often presented. For example, the objectives of the first two units are for students to learn about the observations necessary to make a good weather forecast and about how these observations are organized and presented (e.g., as weather maps, satellite and radar images, etc.). Students take measurements with common weather instruments and compare them with the on-campus weather station. They also learn to identify weather observations, fronts, pressure centers, clouds, and precipitation on surface and upper-air weather maps and satellite and radar images. In everything that comes after these first two units there is an emphasis on applying these weather observations to weather analysis and interpretation, as these observations are the foundation of the scientific method. Often, I have students make real-time observations to help them make the connection between what they see in weather maps and current weather. For example, students might use a thermometer to measure outside temperature at different altitudes along a slope next to a campus building and then calculate the environmental lapse rate. Students might also use current satellite and radar images to determine if there are clouds or if it is currently raining anywhere in the state.

The third and fourth units of the course present the important hypotheses and theories that ultimately allow us to use observations to make weather forecasts. The learning objectives of these units are to verify and apply Archimedes principle, the Second Law of Thermodynamics, the principles of cloud and precipitation physics, and Newton's Laws in an analysis of current weather. For example, students learn that precipitation type is largely determined by the temperatures within the cloud, at the height where precipitation develops (approximately the 850-mb level), and the temperatures near the Earth's surface and are then asked to predict precipitation-type given these temperatures. Students also use current 300 mb maps available online to outline the jet stream based on the 70-knot isotach and then draw a force balance using the wind direction observations and height contours to see that the pressure gradient force and the Coriolis force are in balance in the upper atmosphere, but not near the Earth's surface where friction is significant and local effects dominate.

The final three units help students understand how these weather observations and theories are used to make weather forecasts. Here, students apply many of the tools and methods used on typical radio, television, and Internet forecasts and the special techniques used to forecast severe weather events, such as thunderstorms, tornadoes, ice storms, lake-effect snowstorms, hail, and floods. Students learn how numerical weather prediction (NWP) model output is used for forecast guidance. They also learn how NWP models use weather observations that are interpolated to a grid, how the important physical laws learned in units 3 and 4 are applied to obtain the equations within NWP models, and how various NWP models differ. Students then use current NWP model output to make forecasts for their local area. The application of techniques used in forecasting severe weather typically depends on the semester. When the unit occurs in late fall students focus on ice storm forecasting and look for locations that are likely to receive freezing rain based on locations that are typically favored areas for freezing rain such as on the cold side of, but near, a warm or stationary front. When the unit occurs in April, students apply these techniques to issue severe thunderstorm and tornado watches based on a number of severe weather parameters including lapse rates, wind shear, helicity and Convective Available Potential Energy (CAPE), and a number of severe weather indices.

The primary goal of the course is to have students apply the scientific method and to understand how this method is used to acquire knowledge and make predictions. Students are reminded of the standard model of the scientific method and how the current course unit fits within this standard model as they continually use observations to back up any claims they make in labs and in-class activities regarding weather. Throughout the course, students naturally learn key meteorological concepts, as typically taught in meteorology textbooks, but this is not the primary aim of the course. At the culmination of the semester, students are asked to prepare a typical weather forecast as a television weather broadcaster would. They use the appropriate NWP model maps to forecast high and low temperature and make a precipitation forecast complete with a determination of precipitation type and amounts. The figure on page 5 presents an example of the types of charts from NWP model output that students are expected to use to make this forecast. From this figure they get an estimate of precipitation amount and must also use NWP model surface maps to estimate surface temperature for precipitation type and snowfall forecasts. Typically they are required to forecast for a city that is expecting frozen precipitation, such as southeast Michigan, which, in the figure shown, is expecting frozen precipitation based on the position of the 850-mb freezing line (southernmost blue dashed line labeled 0°C) located south of the region.

Students appear to enjoy the course, with 83% of them rating the course as above average. Furthermore, attendance in this course, which is not graded but is noted in various ways, is typically over 90% on average, which is much higher than traditional science courses for non-science majors.

REFERENCE

Knox, J. A. and Ackerman, S. A., 2005, What do introductory meteorology students want to learn, Bulletin of the American Meteorological Society, v. 86 (10), p. 1431-1435, doi:10.1175/BAMS-86-10-1431