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Standards

Science and Engineering Practices

ask questions and define problem
develop and use models
plan and carry out investigations
analyze and interpret data
use mathematical and computational thinking
construct explanations and design solutions
engage in argument from evidence
obtain, evaluate and communicate information

Standards

Science

4.PS3-2. Make observations to provide evidence that energy can be transferred from place to place by sound, light, heat, and electric currents

PS3-4. Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.

ELA

W.4.7 Conduct short research projects that build knowledge through investigation of different aspects of a topic. 4.PS3-2

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Notes for teachers

Make sure to discuss first the safety precautions before proceeding to the activity.

The fruits used in this activity should not be eaten. Extra care should be observed when handling the LED, metal electrodes and alligator clip leads.

Use fresh, juicy citrus fruits for the best results. Citrus fruits that are too ripe or dried out may not produce enough juice to create a strong battery.

Make sure your metal electrodes are clean and free of any corrosion or rust.

Keep your fruit battery experiment away from heat sources or flames, as the acid in the citrus juice can be flammable.

List of Materials

Acidic or citrus fruits (grapefruit, kiwi, lemon, lime, orange, and tomato)

LED Bulb or light bulb

a copper wire or a penny

a galvanized or zinc nail

a voltmeter or multimeter

Knife to cut the fruit

Alligator Clips on Lead wires

Goggles

Gloves

Alcohol wipes

Recording sheet

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Objectives:

The students will learn electrical terms and concepts.

The students will demonstrate how an electrical current can be generated using citrus fruits that are strong enough to power a small light bulb.

The students will observe and record how long the LED stays lit.

The students will compute and compare the average current produced of the different citrus fruit batteries.

The students will research to investigate other fruits and vegetables that could be used as batteries.

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Agenda (lesson time)

I will allow three class periods for this activity.

Quick Research (KWL Chart)

Unlocking of Terms

Video Presentation

Assembling of Fruit Batteries

Testing/ Troubleshooting

Calculating the Voltage

Group Discussion

Research/Writing Activity

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Intro/Driving Question/Opening

Think-Pair-Share

What is electricity?

Have you ever wondered how it works or how it powers your toys and gadgets?

What are batteries?

How do you think they work?

Is it possible to use fruits as battery?

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Hands-on Activity Instructions

KWL Chart

In pairs, have the students do a quick research on how does a battery work and let them fill out the KWL chart. Have some volunteers to share their work before the class.

Hook Me Up

Direct students attention in learning some terms (conductor, insulator, electron, electricity)
Reinforce the students research by having them watch a video about how does a battery work?

Assembling the Fruit Batteries

Give each group the materials they need to

assemble the fruit batteries.

Roll and squeeze the fruit on all sides with your hands. Make sure not to squeeze too tightly and break the skin.
Approximately 2 inches apart from one another, insert the nails into the fruit. The end of the nails should be in the center of the fruit, but not touching one another.
Attach the zinc electrode all the way into the first fruit to be tested.
Insert the copper electrode on the opposite side.
Using a pair of alligator clips, attach the longer of the two LED leads to the copper strip and the shorter lead to the metal strip using a pair of alligator clips.
Your bulb will light up, when the second wire is attached to the copper nail.
Observe and record what happens.
Measure the current using the multimeter.
Take off the zinc and copper electrodes and wipe off any excess juice.

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Hands-on Activity Instructions

Continuation...

Do the same steps using a different fruit. Record the results for each time.
The entire process should be repeated twice (total of three trials) for a more scientifically-accurate investigation.

Troubleshooting

If the device does not light up, check all the wire connections.
Make sure the metal electrodes are properly inserted into the fruit and are not touching each other.
If the LED light bulb is too dim or does not work, try using a different one with a lower voltage requirement.

Calculating the Current

Compute the average current produced by adding the values from the three independent results (trials) and dividing the sum by three for each fruit.
Record the data in a recording sheet.
Analyze the data to determine which fruit had the highest voltage.

Group Discussion

Have the students answer the following questions:

Using the data, which fruit produced the most electricity? which fruit produced the least?

Why do placing two dissimilar metals into a fruit produce an electric current?

Did changing how far in the electrodes were make the current increase or decrease?

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Hands-on Activity Instructions

Continuation._

Did putting the electrodes closer together make the current increase or decrease?

Did putting the electrodes closer together make the current increase or decrease?

Did the size of fruit make a difference? If so, did the size make the current increase or decrease?

How long did the fruit provide electricity to light the LED?

Wrapping Up

Have the students do research on what other fruits and vegetables might work as batteries aside from citrus fruits. Then, have the students submit a written summary of their research work.

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Assessment

The completed fruit batteries and computation

The completed research output

The students demonstrate how an electrical current can be generated using citrus fruits that is strong enough to power a small light bulb.

3-2-1 Exit Ticket

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Differentiation

A video of a step by step instructions in assembling a fruit battery can be provided for students who are having difficulties using the printed instruction guide.

Remediation

Extension/Enrichment

Have the students create a series circuit using multiple citrus batteries to see if they can increase the voltage.

Try using different types of metals for the electrodes, such as copper and aluminum, to see how they affect the output of the battery.