This document contains a project proposal that examines generating electricity from fruits. The proposal outlines using different fruits as electrolytes in a circuit with copper and zinc electrodes. It summarizes the chemistry behind how redox reactions produce electricity and the relationship between pH and acidity. The objectives are to analyze how fruit freshness affects voltage and pH, and determine which fruits produce the highest voltage based on pH readings. The methodology describes taking pH readings of various fruits and measuring the voltage, current, and time an LED lights when the fruits are used in a circuit with the electrodes. The expected results are that more acidic fruits will generate electricity for a longer time.

1. UNIVERSITI TEKNOLOGI MARA
CAMPUS
NEGERI SEMBILAN
PROJECT PROPOSAL
PHY350
TITLE : THE ELECTRICAL FRUITS
NAME & STUDENT’S ID: i. AIN NORIN
ii. MARYAM ARIFFIN
GROUP : AS1206G1
SUPERVISOR : MDM. ALLINA BINTI NADZRI

2. TITLE: The Electrical Fruits
INTRODUCTION
Batteries generate electricity by transforming chemical energy into electrical energy
through a chemical reaction between two different electrodes and one electrolyte (Giancoli,
2009). The simple batteries contain two plates or rods made of dissimilar metals called
electrodes. The electrodes are immersed in a solution called the electrolyte.
When two dissimilar metals are placed in a common conducting solution (electrolyte)
electricity will be produced this is the basis of the electro-chemical cell or wet cell. An
electric current is a flow of electrons and is measured in units called amperes or "amps."
Voltage is the force that pushes the electrons through a circuit and is measured in volts, a
result known as Ohm’s law. Ohm’s law state that when the resistance R is defined by V=IR,
where I is the current in the device and a potential difference V is applied across it (Giancoli,
2009).
Ohm’s Law: V=IR
V: voltage (V)
I: current (A)
R: resistance (Ω)
Figure 1
According to Yeap T.K, 2007 state that a battery consists of a negative electrode, a
positive electrode and an electrolyte, which conducts ions. The electrons flow from the
cathode through the electrolytes to the anode. The cathode is the negative electrode which
could be the copper wire and the anode is the positive electrodes which could be zinc wire.
This process generates electricity just the same way as voltaic battery.
Redox reactions are a family of reactions that are concerned with the transfer of
electrons between species (Catherine & Edwin, 2006). Like acid-base reactions, redox
reactions are a matched set. We don't have an oxidation reaction without a reduction
reaction happening at the same time. Oxidation refers to the loss of electrons, while
reduction refers to the gain of electrons. Each reaction by itself is called a "half-reaction",
simply because we need two half-reactions to form a whole reaction.
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3. Figure 2: Design of redox reaction process.
The electrons transferred in a redox reaction arise from the change of the valence
state of materials in the redox reaction. If a material gives up or loses an electron, then its
valance state becomes more positive and the reaction is called an oxidation reaction
(Raymond C, 2010). Since an oxidation reaction gives up electrons, it will always have
electrons as one of its products. By definition, the oxidation reaction occurs at the anode.
The chemical reaction shown below is an oxidation reaction where zinc metal with a
neutral valance state or valance charge = 0 is oxidized to give a zinc ion, which has a 2+
valence charge. The two electrons lost by the zinc metal are products of the oxidation
reaction. Since the overall aqueous solution must be electrically neutral, there must also be
ions with positive charge in the solution.
Valance charge of half equation
0 2+
Zn(s) Zn2+(aq)+ 2e-
Figure 3
Figure 3: Oxidation reaction (the valence state of the reactant increases) of zinc metal to
a zinc ion. The (s) after the zinc indicates that it is in solid form. The zinc ion has (aq)
after to indicate that it is aqueous in solution.
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4. A material gains an electron then its valance state decreases or reduces due to the
negative charge of the electrons and the reaction is a reduction reaction (Raymond C,
2010). The reaction below is a reduction reaction in which a copper ion with a valance
state of 2+ is reduced to copper metal, with a valence state of zero. Since a reduction
reaction requires electrons, it will always have electrons as one of the reactants. The
reduction reaction occurs at the cathode.
Valance charge of half equation
2+ 0
Cu2+ (aq) + 2e- Cu (s)
Figure 4
Figure 4: Reduction reaction of Cu ions to form copper metal. The valence state
of copper is reduced from 2+ to 0.
The total redox reaction consists of both of the two reactions together. For the
example of copper and zinc above, the total reaction is shown below. Since the reaction
with zinc metal is the reactant of the oxidation reaction it providing the electron required
to reduce the copper, the zinc is the reducing agent and the zinc itself is oxidized. Copper
ions in this case are the oxidizing agent, they oxidize the zinc and are themselves reduced.
Valance charge of overall equation
Cu2+ (aq) + 2e-+Zn(s) Cu(s) + Zn2+(aq) + 2e-
Cu2+(aq) + Zn(s) Cu(s) + Zn2+ (aq)
Figure 5: The overall equation of reaction between Zn and Cu.
In this science project copper and zinc metals will be used as the electrodes and the
citric acid found in fresh fruit is the electrolyte. The chemistry behind the fruit cell is that zinc
is more reactive than copper which means zinc loses electrons more easily than copper. As a
result, oxidation occurs at the zinc metal strip and zinc metal loses electrons to become zinc
ions. The electrons then flow from the zinc strip to the copper strip through an external
circuit. At the copper strip, reduction occurs the hydrogen ions in the fruit's critic acid juice
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5. accept these electrons to form hydrogen gas; this explains why the investigator may observe
bubbling of gas produced at the copper strip when the two metals are connected by a wire.
Redox reactions, or oxidation-reduction reactions, have a number of similarities to
acid-base reactions. The pH scale measures how acidic or basic a substance is. Acidic and
basic are two extremes that describechemical properties. A substance that is neither acidic nor
basic is neutral. According to Oxtoby (2002), under the Brønsted-Lowry definition, both
acids and bases are related to the concentration of hydrogen ions present. Acids increase the
concentration of hydrogen ions, while bases decrease the concentration of hydrogen ions (by
accepting them). The acidity or basicity of something, therefore, can be measured by its
hydrogen ion concentration. The pH of a substance can be determined using:
pH = log10[H+]
[H+] is a concentration of hydrogen ion
A base in chemistry is a substance that can accept hydrogen ions (protons) or more
generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and
releases hydroxide ions (OH−) quantitatively. A strong base is a base which hydrolyzes
completely, raising the pH of the solution toward 14 (Lawrie, 2000).
An acid in chemistry is a substance that can donate hydrogen ions (protons) or more
generally, accept electron pairs. Aqueous acids have a pH of less than 7, where an acid of
lower pH is typically stronger, and turn blue litmus paper red (Farnworth, 2000). Chemicals
or substances having the property of an acid are said to be acidic.
Figure 6: pH scale with a different concentration
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6. ABSTRACT
In this experiment, we use a variety of fruits to compare the pH meter reading,
voltage, current and time of the LED working. We always use battery to get electric sources
but it harmful and hard to compose. So, we replace the battery by using the fruits. The fruits
will produce electric that convert from chemical energy to electrical energy. Next, we use
Copper and Zinc plates as an electrode, the combination of Copper and Zinc electrode will
give the highest voltage compare to other electrodes. The redox reaction will happen when
two electrodes (Zinc and Copper) connected to the fruits. The Zinc will undergo oxidation
process whereas Copper will undergoes reduction process. Then, electron will move from
anode (Zinc electrode) to cathode (Copper electrode) and can cause the LED to light up.
Expectation Result:
At the end of this experiment we expect that acidic is needed to contribute in generate
electricity to light a LED. The more acidic solution in the fruit, the longer time of LED to
light up.
In determining the effect of pH value to generated electricity, we need to use
difference type of fruits. There is a property in fruits that can generate electricity which is
citric acid. The fruit with the most acidic of pH meter reading will create the most electricity.
BACKGROUND PROJECT
In this project, we used different type of fruits as a function of electrolytes that’s can
convert chemical energy to electrical energy. The Light Emitting Diode (LED) is used to
indicate if the fruit-cell is generating an electric current. A LED is a semiconductor device
which converts electricity into light. An electric current can flow only in one direction
through LEDs which means that they have a positive and negative terminal, also referred to
as the anode and cathode. The cathode should be connected the negative zinc metal strip, and
the anode to the positive copper strip. LEDs have their cathode and anode marked in some
manner usually the anode wire is often the longer of the two leads.
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7. We also study effect of pH reading of difference type of fruits in generated electricity.
The fruits with higher concentration of H+ ion will become more acidic. The value in pH
meter reading is nearer to 1 because of high H+ ion concentration. The fruit with the most
acidic of pH meter reading will create the most electricity (Corissa, n.d.).
Since we are using different types of fruits, we need to consider about their size, mass,
freshness, the total fruits we are using and also the distance between electrodes. All five
behaviours bring a side effect for our experiment and we need to reduce the side effect by
making the size, mass, the total fruits and distance between electrodes to be constant and we
also try to get the highest freshness of these fruits (Lucinda, n.d.). Other than that, we will
repeat the experiment three times and calculate the average for voltage and pH value.
The variable of this project:
Manipulated variable: difference type of fruits.
Constant variable: size, mass and the total of fruits, distance between two electrodes.
Responding variable: pH meter reading, voltage, current and time of LED working.
OBJECTIVE
1) To analyse the freshness of fruit would affect the voltage and pH of the fruit.
2) To determine which fruits will produce high voltage according to its pH reading.
METHODOLOGY
Materials:
Difference type of fruits (banana, star fruits, orange, lemon, green apple, tomato and
potato are available).
Knife.
pH meter.
Copper and zinc electrodes.
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8. Stopwatch.
Multimeter (to measure voltage and current).
Alligator clips.
Light Emitting Diode (LED).
Figure 7 : All materials of project
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9. Procedure:
Insert the copper and zinc
Take the pH meter and
electrodes into the fruit with 6cm
hold it onto the fruit and
distance between two
take the reading of pH
electrodes, the fruit and the
meter.
electrodes must touching each other.
Use an alligator clip to connect the
Record the reading electrodes to the multimeter to measure
of multimeter. voltage between two electrodes and current
passing through the multimeter.
If the LED lights up, takes
Disconnect to multimeter and
the time by using
connect alligator clips with
stopwatch and record how
LED.
long the LED stays lit.
Repeat steps 1 Repeat steps 1
until 8 with the until 7 two times
differences with the same type
type of fruits. of fruit.
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10. Figure 8
Firstly, we want to know the reading of pH meter for the fruits. Take the pH meter
and hold it onto the fruit and take the reading of pH meter. Difference type of fruits contains
difference reading of pH meter. Next, insert the copper and zinc electrodes into the fruit, the
distance between two electrodes must fixed to 6cm to get an accurate value of multimeter.
The fruit and the electrodes must touching each other. Then an alligator clip is used to
connect the electrodes to the multimeter to allow the electrons flow from the zinc electrodes
to the copper electrodes through an external circuit. Multimeter will measure voltage between
two electrodes and current passing through the multimeter. Take the reading of multimeter.
Finally, an alligator clip is disconnected to multimeter and connect alligator clips with LED.
If the LED lights up, takes the time by using stopwatch and record how long the LED stays
lit, difference type of fruits will have difference time of LED to stay light up. The experiment
is repeated two times with same type of fruits to reduce error and repeat again with difference
type of fruits to compare the pH meter reading, voltage, current and time of LED working.
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11. TABLE OF RESULTS
Multimeter reading.
FRUITS VOLTAGE (V) AVERAGE CURRENT (A) AVERAGE
TRIAL TRIAL TRIAL VOLTAGE TRIAL TRIAL TRIAL CURRENT
1 2 3 1 2 3
LEMON
STARFRUITS
ORANGE
BANANA
APPLE
TOMATO
POTATO
PH meter reading.
FRUITS PH METER READING AVERAGE
TRIAL 1 TRIAL 2 TRIAL 3 READING OF PH
METER
LEMON
STARFRUITS
ORANGE
BANANA
APPLE
TOMATO
POTATO
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12. REFERENCE
Anne M.H. (n.d.). Oxidation Reduction Reactions - Redox Reactions. Retrieved Disember 9,
2011 from http://chemistry.about.com/od/chemicalreactions/a/oxidation-reduction-
reactions.htm.
Anthony C. Acids and Bases. (n.d.). Retrived Disember 9, 2011 from
http://www.visionlearning.com/library/module_viewer.php?mid=58.
Bonder Research Web. (n.d.). Oxidation and Reduction. Retrieved Disember 9, 2011 from
http://chemed.chem.purdue.edu/genchem/topicreview /bp/ch9/redox.php
Catherine E.H. & Edwin C.C. (3rd ed.).(2006). Chemistry: Pearson Education Limited.
Chemistry Syllabus and Notes. (n.d.). Oxidation and Reduction. Retrieved Disember 10,
2011 from http://ibchem.com/root_htm/about.htm
Corissa K. (n.d.). Citrus Fruit Science Projects. Retrieved December 12, 2011 from
http://www.ehow.com/list_5981005_citrus-fruit-science-projects.html
Douglas C.G. (4thed.).(2009). Physics for Scientists and Engineers with Modern Physics:
Person Education International.
E. Farnworth.(April 2000). The Acidity of Food. Retrived December 12, 2011 from
http://www.medicinalfoodnews.com/vol04/issue4/acidity.htm.
Lucindar S.(n.d.). Electric Fruit. Retrived December 12, 2011 from
http://www.lucinda.net/surber/fruit.html
MiniScience.Com. (n.d.). Make Electricity from fruits. Retrived December 13, 2011 from
http://www.miniscience.com/projects/FruitElectricity/
Raymond C. (10thed.).(2010). Chemistry. New York: McGraw-Hill.
Sciencefairadvanture. (n.d.). Fruit Battery Power. Retrived December 13, 2011 from
http://www.sciencefairadventure.com/ProjectDetail.aspx?ProjectID=154.
Yeap T.K. (1st ed.).(2007). Chemistry: Pearson Longman.
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13. Lawrie R. (1st ed.).(2000). Advance Chemistry for you: Nelson Thornes.
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