Potato Battery

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VIDEO LINKS:

Part 2
  1. Making a potato battery

Data analysis and calculations (Use these if you need help with your data and calculations)

  1. Introduction to electrochemistry:
  2. The electrochemistry experiments:

The prelab must include Experimental Protocol, Chemical Table and Equipment Table.

The lab report requires all sections (including prelab sections) to be completed in one document.

Experimental Protocol

(Analysis) Watch the experiment videos.  Take notes on the protocol.  Stop the video and re-watch as necessary to acquire the details of the procedure.  Write out the protocol for each part of the experiment.  (It can be written in sequential steps.  Complete sentences are not necessary.)  This is the protocol you will follow, so be detailed.

Chemical Table

(Representation) Prepare your chemical table including the materials you will use in the experiment.  Here is a general template that you may use.  
Chemical Name Chemical Formula Molar Mass (g/mol) Hazards reference PPE
Sodium Chloride NaCl 58.5 Skin irritation https://fscimage.fishersci.com/msds/21105.htm  
           
           

Equipment Table

(Analysis) Identify the equipment (type AND size) needed for the experiment and include the name and an image of each.  Be sure to describe the equipment, how to use it, and why it is suitable for this use.
Equipment Name Equipment Picture Intended Purpose

Data Collection

(Acquiring competencies) Following your detailed protocol based on the videos, perform all the experiments. Record your observations and take pictures of your key steps in the process.  Your observations and images need to be incorporated in your data section and this section should be as detailed as possible as you will use this information to complete your discussion.

Data Processing

Making a potato battery
  1. (Experimental design) Select a variable (temperature, pH, type of fruit, type of vegetable, etc.) that you will study as a team. Each team member will then select a different condition of the variable (ex. apple, instead of potato, etc), and create a new battery. Write a detailed protocol.  Show the pictures of the new batteries at different conditions side-by-side with the student inventor in the frame.
  2. (Representation) Write the overall reaction that occurs.
  3. (Representation) Draw the diagram for the galvanic cell in this experiment, indicate the direction of the electron flow and label the electrodes.
  4. (Assumptions and Analysis) Fill in the following table using the observations and data from your experiments.
Assumptions made Testing the assumption If assumptions are wrong ...
Electrons flow more easily without cell walls. Repeat experiment with cooked vegetable. Same or less current will flow.
 

Discussion

Write a minimum one-page (12 font, single spaced) discussion on the experiment conducted this week. Address at least one question in each category as fully as possible integrating the collected data, providing explanations for the observed trends, and evaluating whether your original assumptions about the experiment were validated by the results. The assignment will be graded on completeness, clarity of the explanations and the meaningful integration of the collected and calculated data. Correct grammar and appropriate format for the chemical formulae and chemical reactions is expected.
  1. Interpretation) Classify the reactions observed in the experiment and provide a supported argument for your choice.
  2. (Existing knowledge, research, and views) Define galvanic cell, electrolytic cell and voltaic cell. Give an example for each from your experiment.
  3. (Existing knowledge, research, and views) Define the half-cell, and describe how they work using the experiment as supporting evidence.
  4. (Existing knowledge, research, and views) Describe the relationship between the half-cell potential and the cell potential. Use your experiment as supporting evidence. (Include the units, why some potentials are positive and some negative, and the information gleaned from those numbers.)
  5. (Analysis) A galvanic cell has a barrier between the anode and the cathode, whereas the electrolytic cell does not. Evaluate whether it is possible to have a galvanic cell without a barrier and provide a supported argument for your selection.
  6. (Analysis) The anode and the cathode were separated in the experiment. Provide a supported argument for why they were never in contact with each other during the experiment.
  7. (Existing knowledge, research, and views) Describe what metals are used in the manufacture of the penny and the galvanized nail.
  8. (Analysis) Compare the results obtained from your team experiment. Describe how modifying the selected variable impacted the performance of the resulting battery.
  9. (Assumptions and limitations) Car batteries run at a minimum of 12.6 V. What would have to be true for a potato battery that generates sufficient voltage to replace your car battery? Provide a supported argument for your choice.
  10. (Manipulation) Assuming a potato costs thirty-three cents and can generate 0.5 volts, calculate how many potatoes, and at what cost, would be needed to run and generate 110 volts. Show your calculations.
  11. (Assumptions and limitations) What would have to be true for your 110 V potato battery to become a suitable replacement for one of the electrical outlets in your house? Provide a supported argument for your choice.