Generating electricity from fruit

Generating electricity from fruit

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses

A: Planning

Task

Your task is to determine which fruits will generate electricity, and to find the maximum voltage that each fruit can produce.

Materials:
Wires; voltmeter; zinc and copper electrodes; fruit (lemon, kiwifruit, apple, tomato).
 
Write a method for how you will go about doing this task.
 

 
 
 
 
 
 
 
 
 
 
 
B: Processing
Draw up a table in the space below to show your results. Remember to include: 

  • a title for the table;
  • headings for the columns; and,
  • the units you need to use.
 

C: Evaluating
Below is a set of results from an experiment where the voltage produced by different fruits has been measured by using a voltmeter with zinc and copper electrodes. The voltage produced, as well as the pH of the fruits, has been recorded. 

 

Fruit

pH

Voltage Produced

Trial 1

Trial 2

Trial 3

Average

Kiwifruit

2.8

.86

.85

.84

   

Lemon

2.2

.94

.92

.93

   

Tomato

4.2

.60

.62

.61

   

 

a)
Complete the "Average" column for each fruit.
 
b)
What pattern or trend is there in the results between the pH and the average voltage produced?

______________________________________________________________________

______________________________________________________________________

 
c) Draw a bar graph of the results of fruit and voltage produced. Remember your graph will need:

  • a title,
  • a label for the fruit on the x axis,
  • an even scale and units on the y axis
 

 

Task administration: 
Equipment:
Voltmeter; wires; zinc and copper electrodes; lemon; kiwifruit; apple; tomato.
  • This task assesses students ability to design and conduct an investigation.
  • This resource has three sections; A: Planning, B: Processing, and C: Evaluation.
  • Students will need to have had prior experience using voltmeters and electrodes.
  • Students can be given time to use the equipment before deciding on, and writing up their method.
  • The section; C: Evaluation can be carried out separately to the other two sections.
  • The class could pool their results for greater accuracy and to address repeat trialling.
Level:
5
Curriculum info: 
Science, Investigating in science, Physical World
Keywords: 
physical inquiry, energy, electricity, voltage, experimental design
Description of task: 
This practical task requires students to plan, process, and evaluate an investigation on types of fruit and the voltage that each can produce.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Gather and interpret data
This resource provides opportunities to discuss the methodology of fair testing.
 
Capability: Interpret representations
This resource provides opportunities to discuss the relative benefits of using tables or graphs to convey the same set of data
and the role that science knowledge plays in being able to interpret a graph/diagram.
 
Science capabilities: 
Gather and interpret data, Interpret representations
Answers/responses: 
A: Planning
Students' method should contain the following points:

  • The electrodes will be placed in each fruit, and connected to the voltmeter. The voltmeter is used to record the voltage.
  • Mentions repeat trialling.
  • The voltmeter is used to record the voltage.

B: Processing

  • The title of the table connects fruit and voltage.
  • One column/row has voltage produced, the other name of fruit.*
  • The unit for voltage is present.

* The tables produced can show variation in structure.
 

a)

C: Evaluating
Kiwifruit-average = .85
Lemon-average = .93
Tomato-average = .61
b) The lower the pH the greater the (average) voltage produced.
c)
  • The title includes fruit and voltage produced (pH optional).
  • The x axis contains the 3 fruits (named) and the fruits are spaced evenly apart.
  • The y axis has a scale from 0 to 1.0, it has a label and unit.