05 Experimental

2021 Topic:  Physical Chemistry of Your Microwave

Determination of Microwave Energy, Flux, Power (Joules / second) and Efficiency:    Calorimetry:  Chemistry, Apparatus Construction, Presentation

Objective 

Many of us have gotten more familiar with our microwave over the course of the last year.  Folks who would never have reheated a meal were cautiously "nuking" take-out "just in case".  But what is a microwave?  How does it operate?  What are the principles involved - and how can we test them?

Construct an Experimental Set Up, and Demonstrate the Experimental Determination of Heat Evolved (Calories or Joules / Unit Time) from a Microwave Oven. 

Perform an experiment to accurately measure the energy flux – amount of heat (energy) resulting / second from the microwave Power Source.  

  • Objective is for the research team to acquire information on construction of a: Research Scale –  Energy Measurement Method. Students select / design, then construct and demonstrate its operation, collect data, write up and report results.
  • The Energy (Heat) Measurement System, the Data and Performance will be evaluated.
  • The research project will be evaluated on the basis of: apparatus construction, operation, safety, and quality of results.

The intent is to use household objects / items that can be borrowed or purchased for a small amount of money.  Any vessel that is microwave-safe is a potential container - discuss why you selected your container.  As with any equipment, safety first when using the microwave and performing the experiment.

 

Requirements 

  • Search for background information on the construction and operation of an experimental - Lab Scale Heat measurement system.  
  • Decide on an apparatus.
  • Assemble, Test and If Needed Refine the Apparatus, Perform Experiments.
  • Record your data and perform all needed calculations / determinations of your calorimetric measurements and temperatures.
  • Write a paper that presents the results and demonstrates your understanding of the chemical principles involved in the chemistry, operation and construction of the microwave (background) and your apparatus (focus). 
  • Present a drawing or picture of your Equipment / Apparatus.
  • Event Day: - teams are expected to have a physical working model of their calorimetry system available for virtual review by the judges and give a PowerPoint presentation of the experiment with presentation of their results. Students will not have to use a microwave on event day, just show the apparatus used in the microwave for the experiment.

Device Construction and Operation

Energy Flux  (Joules/Second) from Power Source  Procedure 

  1. Fill the reactor vessel with water that is near 0 oC  ( Temp. between about 5 and 0 degrees C) Measure the temperature and volume accurately (± 0.5C).            Note:  There Should be NO ICE in the Cold Water; but separate experiments could be performed with water and ice present, as microwave ovens do have defrost operation.
  2. Place the low temperature water / filled reactor vessel into the microwave oven and perform the required runs, each time starting with a cold water filled reactor vessel in the microwave oven.
  3. Required runs:   Start with reactor filled with water near 0 oC  (each run) at 100% power and run the microwave for:  1.0 minute, 2.0 minutes, 3.0 minutes, 4.0 minutes
  4. Each run starts with initial H2O temperature near 0o C  Record initial and final temperature accurately.
  5. Determine Total Enthalpy H input to the Reactor System = Cp (H2O) * ∆T + Cp Reactor * ∆T
  6. Plot data.  Determine / Report Energy Flux (Joules/Sec) of the Microwave Reactor Power Source with the Microwave Source at 100% Capacity.

Student Research

  • The written research report should describe the chemistry:  the chemical reactions and principles. Include chemicals and methods that produce and that collect the energy and the steps that convert the experimental data into energy, as well as possible sources of error.
  • Report should include the following:
  1. A materials list with a verifiable cost value in terms of supplies used to construct the working reaction vessel.
  2. A labeled picture of the apparatus, illustrating parts and materials. 
  3. Experimental approach and factors used to design the apparatus.  
  4. Provide a materials list with a verifiable cost value in terms of supplies used to construct the apparatus.
  5. A labeled picture or set of pictures of the apparatus should be available identifying parts and materials 
  6. Steps in Conversion of measured Experimental data into Energy evolved  

   Event Day  - PowerPoint presentation of the experimental set up, its operation, collection of data, calibration of components if needed, calculation of energy evolved. 

Report Guidelines 

  • The report and presentation should describe the reactor energy source and any chemical reactions or physical changes occurring. Include and principles that allow measurement and calibration of the amount of energy. 
  • Research report and presentation further guidelines below.
  • Sources of information must be identified (written sources as well as a list of people who provided assistance).
  • Research reports should be based on information acquired from a minimum of one PRIMARY SOURCE.  Internet sources may be utilized in addition to the primary sources. Judges will be looking at how students select and use information gathered from primary sources.
  • Examples of primary sources include articles found in peer-reviewed professional journals such as Nature, Science and Journal of Chemical Education, Journal of Chemical Engineering Education. Peer-reviewed professional journals are available at post-secondary academic libraries.  Peer-reviewed journals that are accessed online are acceptable.  Magazines such as Discover, Science News, Popular Science and Scientific American, although informatory are not peer-reviewed professional journals. You are required to submit copies of the first three pages of each primary source used in your report.
  • Conclusions you form should be based upon your; experimental data, experiments you conduct and data you collected and interpreted at your school facility.  
  •  
  • Your written report should not exceed six pages - 12 pt., 1.5 or double spaced plus a  reference section)  
    • A cover page containing:  Title of the Report, Authors, School ID, Team (A or B if applicable). 
    • Text  starting with an Abstract, then continuing with the Experimental Method, Set up Diagrams, charts, etc. An abstract is a summary of the experimental method, and then the results, typically less than 1 page.
  • A schematic diagram of all components used in the measurement
  • Collected and analyzed test data (demonstration of operation and testing)
  • Results and conclusions.
  •  Part 2 (References) • Copies of: Abstract and important experiment description page(s) of the primary reference source articles used in your research. • A list of references used in your research (written sources as well as a list of people who provided assistance).

Event Day (The presentations will be virtual via Zoom, WebEx, or a similar program).

  • Prepare a presentation (PowerPoint) that summarizes your experiment and research results. Presentations should reflect the information and data presented in the written report. Schools should supply their own computers. 
  • Be prepared to make a  10 - 12 minute oral presentation, including Q&A with the judges.
  • An electronic copy of the complete report and the presentation file in .pptx format should be received by the Director of the NJCO by the deadline indicated in the Competition Guidelines. The reports must be clearly labeled with the school name.  If there is more than one team for your school, also indicate Team A or B, etc.
  • Teams are required to submit both their research report and presentation to Turnitin.com for review. Submissions should be a single .docx file for the report and a single .pptx file for the presentation.  Review and possible assessment of penalties or disqualification due to Turnitin score is the sole discretion of the judges.
  • Make sure to have a copy of your report and your presentation available for reference on the day of the event.

Judging

  • Written report with Description and Results  - 20% 
  • Apparatus Design, Construction and Operation, Innovative-ness, safety)  - 20%
  • Technical knowledge of the method - 20%
  • Experimental Measurements and Calculations - 20%
  • PowerPoint – and  Oral Presentation / Explanation of Principles of Operation - 20%

Team Identification

It is important to identify all submissions with the information below, to prevent a mix-up.  Schools with multiple teams – Please clearly differentiate between team A and B (etc.)

Each submission (research reports, CDs, DVD, reports, etc) must include the following 4 items:

  1. Name of school
  2. Team designation, if applicable (A, B, etc.)
  3. Names of students             
  4. Name of coach

All files and presentations will be handled electronically.  Please DO NOT send any papers or CDs to us!