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# Model Inquiry [sorta] Laboratory Activities for Teaching about Thermodynamics of Energy Sources and Resources

Steven Semken (Arizona State University), Timothy Schroeder (Bennington College), Richard Kettler (University of Nebraska, Lincoln)

This is an in-progress compilation of simple, inexpensive, modular, inquiry-based laboratory experiments or demonstrations, from online or printed sources. These can potentially be used in a variety of settings and lessons for learning about some basic thermodynamic and other physical principles of energy sources and energy resources.

## Measure and compare the energy densities of different fuels obtained by combustion and calorimetry.

Liquid fuels: Measure and compare the heats of combustion of liquid fuels using a metal-can calorimeter and spirit burners containing the different fuels. For example, see http://www.practicalchemistry.org/experiments/measuring-heat-energy-of-fuels,21,EX.html OR http://www.hi.com.au/chemtwotrb/Chtwo_58.doc (This link no longer works, but it refers to the following text: Heinemann Chemistry Two); there is also an example that can be watched on YouTube: http://www.youtube.com/watch?v=OpKKh7tU5Z0

Solid fuels: Measure and compare heats of combustion by burning small quantities of different solid fuels (e.g., wood, charcoal) in a holder beneath a metal-can calorimeter; see http://www.chymist.com/energy%20of%20a%20peanut.pdf for an example of an apparatus that can be constructed.

## Explore the significance of heating water in total residential energy consumption.

• This is an addendum to the previous activity.
• At least 17% of residential heating is devoted to heating water and much of our energy consumption in generation of electricity is used to heat water. Partly this results from the high heat capacity of water.
• Equipment: spirit lamp, beakers, thermometer, scale, water, silicone oil.
• Allow the water and silicone oil to reach room temperature. Weigh the spirit lamp with fuel. Weigh out a quantity of water into the beaker. Heat with the spirit lamp until the temperature increases by 20 degrees C. Extinguish the spirit lamp and reweigh. Calculate the amount of fuel used. Weigh out an amount of silicone oil equal to the amount of water used. Heat with the spirit lamp until the temperature increase by 20 degrees C. Weigh the spirit lamp and calculate the fuel used.
• This activity demonstrates the high heat capacity of water compared to other items. Heating of water using passive solar systems could reduce carbon emissions significantly. Measure the amount of water that could be heated from 15 degrees C to 80 degrees C using the sunlight that strikes a typical rooftop in your area over the course of one day.

## Measure hydroelectric power output at varying head and apply the findings to real hydroelectric systems.

• Instructor or students first must construct or purchase a simple tabletop hydroelectric generator.
• Students use the apparatus to conduct experiments to measure the power output in watts at a range of heads and flow rates.
• Students then analyze their measured data by graphing it and writing a best fit equation.
• They can then compare their relationship equation to the derived equation for hydroelectric power output: P(kW) = Q(m^3/s x H(m) x 9.81(m/s^2) x efficiency of system
• The students then compare their findings to the data from a real hydroelectric system for which the dam height and power output can be determined.
• Alternatively, students can obtain average discharge data from USGS ( http://waterdata.usgs.gov/nwis/rt ) for a local river, determine where and how tall a dam could be built on that river using topographic maps (https://www.usgs.gov/products/maps/topo-maps), and then estimate the power output from a hydroelectric generator at that dam.
• The activity could be extended to a study or discussion of the environmental and social impacts of building such a dam and power plant.

## Measure wind power output at varying wind speed and apply the findings to real wind systems.

• Instructor or students first must construct or purchase a simple tabletop wind generator.
• Students use the apparatus to conduct experiments to measure the power output of their system at different real or simulated wind speeds. This step will require a simple aerometer.
• Students then analyze their measured data by graphing it and writing a best fit equation.
• They can then compare their relationship equation to the derived equation for wind power output:
• P = 0.5 x air density x Turbine Area x WindVelocity^3 x Coefficient of Performance x System Efficiency.
• These data can be used to investigate the differences between linear and power-law relationships.
• Students may then use real wind speed data for their local area (available from the American Wind Energy Association) to estimate the power output from several turbine designs in a hypothetical wind farm.
• The activity could be extended to a study or discussion of the environmental and social impacts of building a wind farm.
Inquiry Laboratory Activities for Thermodynamics of Energy Sources and Resources (Microsoft Word 46kB May19 09)