Can We ‘Grow’ Electricity?!Zhi Wei Ngion, Tiffany Park, Leo Siha, Amy Wan, Sherry Zhang

G4Group #1 ★G4

Introduction

• Generating power produces – Pollution– Global warming

• Lemon and potato as power sources:– Clean– Renewable– Biodegradable

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Physics

Experiment• Voltage output

of lemon & potato batteries

• How time affects the battery’s effectiveness

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PhysicsData Presentation

Experiment I

day 1 day 2

lemon voltage ± 0.001V lemon Voltage ± 0.001V

1 0.985 1 0.993

2 0.990 2 0.951

3 0.973 3 0.989

4 1.000 4 0.963

5 1.008 5 0.950

Average 0.991 Average 0.969

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PhysicsData Presentation

Potato Voltage ± 0.001V Potato Voltage ± 0.001V

#1 0.808 #1 0.743

#2 0.895 #2 0.814

#3 0.928 #3 0.794

#4 0.938 #4 0.940

#5 0.992 #5 0.857

Average 0.912 Average 0.830

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PhysicsConclusion

• Lemon batteries’ potential difference (voltage output) are relatively larger

• Average potential difference (voltage output) of the batteries decrease as time increases

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ChemistryHow do lemon batteries create electricity?

Oxidation-reduction (redox)

• These reactions involve the transfer of electrons between substances.

• Redox reactions release energy, and this energy can be used to do work if the reactions take place in a voltaic cell.

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•The cell potential is a measure of the difference between the two electrode potentials.•The standard electrode potentials, Eo , in aqueous

solutions of Cu and Al are +0.34 and –1.66 V with reference to hydrogen H. •The cell voltage of the ”lemon battery” is the

“difference”, U = (+0.34) – (-1.66) = 2 V.

ChemistryStandard Electrode Potentials

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Chemistry

To investigate the relationship between the acidity of the lemon and its voltage output.

Experiment

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Experiment II

ChinaVoltage

± 0.001 VpH ± 0.1 Thailand

Voltage ± 0.001 V

pH ± 0.1

1 0.961 3.0 1 0.948 2.8

2 0.991 2.9 2 0.976 2.8

3 0.505 3.0 3 0.517 2.9

4 0.947 3.0 4 0.947 2.9

5 0.964 3.3 5 0.955 2.9

6 0.976 3.0 Average 0.869 2.9

7 0.969 3.1

　8 0.940 3.2

9 0.957 3.1

10 0.947 3.1

Average 0.916 3.1

ChemistryData Presentation

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ChemistryData Presentation

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ChemistryData Presentation

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• UNABLE TO PROVE: Linear relationship between voltage and acidity

• The conditions of the electrodes will affect the voltage of the battery

ChemistryConclusion

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To investigate the geographic origins & mass of the lemons.

Also the relationship of the mass of lemon with its voltage output.

Experiment

Biology ★

Biology

Lemons from the USA

Mass ± 0.1g

Voltage ± 0.001 V

pH ± 0.1

1 164.13 g 0.907 3.0

2 179.75 g 0.946 2.9

3 155.31 g 0.914 3.0

4 173.60 g 0.906 3.0

Average 168.20 g 0.918 3.0

Data Presentation

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Biology

Lemons from China

Mass ± 0.1g

Voltage ± 0.001V

pH ± 0.1

1 109.82 g 0.969 3.1

2 115.83 g 0.940 3.2

3 110.44 g 0.957 3.1

4 100.17 g 0.947 3.1

Average 109.07 g 0.953 3.1

Data Presentation

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BiologyData Presentation

2.85

2.90

2.95

3.00

3.05

3.10

3.15

3.20

3.25

90.00 110.00 130.00 150.00 170.00 190.00

pH

leve

l

Mass (g)

pH level vs. Mass

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BiologyData Presentation

Voltage vs. Mass

0.9

0.91

0.92

0.93

0.94

0.95

0.96

0.97

0.98

90.00 110.00 130.00 150.00 170.00 190.00

Mass (g)

vo

lta

ge

(V

)

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BiologyConclusion

• Both sets of data are randomly scattered • Mass does not effect the voltage output of

the lemons

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Conclusion and Evaluation

Statistic values20W light bulb

– 2.5 mg of coal (1 second)

– 2.5 kg of coal (11.5 days) cost: 2.5 RMB• 108 lemons can provide the amount of voltage to

power 27 LED• The light energy given out by 27 LEDs equals to

120W light bulb • 234 lemons can provide the amount of voltage to

power 120W light bulb• 108 lemons (from mainland China) cost 216 RMB

Physics

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• Effectiveness of lemon batteries– Individually and in groups

• Time factor:– Lemons biodegrade

Lemon battery Voltage ± 0.1V

Series of batteries

Voltage ± 0.1V

1 0.9

2.12 0.93 0.7

Total voltage 2.5

Conclusion and EvaluationPhysics

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• Effects of electrodes on the lemon battery- Surface oxidation- Electrochemistry potential

Substance Standard electrode potential

Lithium ﹣3.04

Magnesium ﹣2.37

Aluminum ﹣1.66

Zinc ﹣0.76

Iron ﹣0.44

Copper ＋ 0.34

Silver ＋ 0.80

Conclusion and EvaluationChemistry

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• Economic costs for the electrodes

• Effects of acid in lemon on the electrodes- Corrosion of metal• Requirements for the redox reaction- Must be electrically connected- Could be provided by just the lemon juice

Metals Cost (RMB per ton)

Magnesium 15.4 thousand

Aluminum 15.3 thousand

Copper (electrolyze) 59.0 thousand

Zinc 16.4 thousand

Conclusion and EvaluationChemistry

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• Lemons can be genetically altered to become smaller in size therefore more space efficient

• lemons are only able to bear fruit year round when grown in mild climate

• Transportation of lemons

• Areas to mass produce lemons1. Building Greenhouses 2. Opening more areas for plantation3. Not enough space

• Effect of mass production of lemons on other plantation

• Use of water

Conclusion and EvaluationBiology

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• Not enough lemons affected accuracy of data

1. Variety of sizes

2. Variety of locations

• Time

1. Grow lemons under different conditions(e.g. soil pH)

Conclusion and EvaluationBiology

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Thank You! ★