THE STUDY OF VOLTAGE PRODUCED FROM CITRUS FRUITS. Keely Murphy. Cary Academy ABSTRACT

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1 THE STUDY OF VOLTAGE PRODUCED FROM CITRUS FRUITS Keely Murphy Cary Academy ABSTRACT The purpose of this study was to determine which type of citrus fruit produces the most voltage. When copper and zinc are poked into the fruit, it becomes a wet cell and acts like a battery. A copper wire and a zinc nail were both poked into four citrus fruits and each of the four fruits was connected to a multimeter which measured the voltage. It was determined that the lemon and the grapefruit produced the same amount of voltage and had the most voltage and the lime was determined to have the lowest voltage. The fruit that were more acidic clearly produced more voltage than the fruits that were less acidic. INTRODUCTION Voltage is a measurement of electrical pressure in a circuit. It measures the electric current that travels from one end of a wire in a circuit to the other end. The current travels like that because there is more potential energy on one end of the wire than the other. When power surges happen the voltage increases in electricity lines. Power surges are caused by lightning strikes and the electric pressure in the electrical lines is increased by millions of volts when a power surge happens. If the increase of voltage in the electrical lines lasts for one or two nanoseconds it is called a spike. If the increase in electricity lasts for three or more nanoseconds it is called surge. The definition of voltage is literally an electromotive force or potential difference expressed in volts. Voltage is also the potential energy that makes the electric current flow. It is the potential difference between two points in an electrical field. Voltage pushes the electrons around as it moves through a circuit. Voltage is basically the push in an electrical current. When there is more current in the circuit, there is more voltage produced.

2 Fruit is made up of a mixture of chemicals that is called an electrolyte. An electrolyte allows charges to flow. An electrode is the part of a cell through which charges enter or exit. Each cell has a pair of electrodes from conducting materials. There are chemical changes between both the electrodes and the electrolytes. These changes convert the chemical energy to electrical energy. There are two kinds of cells in electricity. These two types of cells are wet cells and dry cells. Wet cells are liquid cells like the cells in a car battery. A lemon also has wet cells which is a reason why it acts like a battery and is able to produce voltage. Dry cells are paste like or solid cells like the ones in a flashlight or a small radio. A lemon is able to convert to a wet cell when copper and zinc are put in it. The lemon juice is the electrolyte and the zinc and copper are electrodes. When both of them are put together, they create an electrical energy. The zinc and copper are like the negative terminal in the battery and the lemon is the positive terminal. The lemon has an acidic quality and that is another reason why the lemon acts like a battery. It is also a reason why it can produce voltage. A lemon is a citrus fruit, which has citric acid, and a battery also has acid. This is also true for other citrus fruits or fruits with a type of acid in them. Just one lemon or one lime can t light a light bulb because it doesn t produce enough voltage to do that. With four or five lemons or limes only a small LED bulb can be lit. A multimeter is a digital meter that measures multiple things. It acts like a bunch of different meters put together into one meter. A multimeter can be used for different purposes. It carries an ammeter, a voltmeter and even a thermometer. An ammeter measures the amount of electrical current that flows through a circuit. To measure current, an ammeter is connected in series in the current. This is so that the ammeter can measure all of the current. The greater the current in the circuit the higher the numbers are on the multimeter. The multimeter also carries a voltmeter. A voltmeter is a meter that measures the amount of voltage in a circuit. To measure the amount of voltage in a circuit, the voltmeter is connected parallel to the circuit. It is connected like this so almost no current flows through it. The more volts that the circuit produces, the higher the numbers are on the multimeter. The multimeter also carries a thermometer. A thermometer is a meter which measures the temperature. It measures how hot or cold something is. A thermometer measures the temperature of anything. The hotter the temperatures, the higher the numbers are on the multimeter.

3 An experiment that has been done in the past is one that studied which citrus fruit produces the most electricity. This experiment has been done by a prior 6 th grade student named Kayla Haeussler. Grapefruits, lemons, limes and oranges were tested. Each fruit was measured in voltage. Different conductors were used and the results were that the lime produced the most voltage. The lime had produced V. The orange had the second highest with V then there was the grapefruit with V. The fruit with the lowest voltage was the lemon with V. The hypothesis was wrong. The hypothesis was that the lemon would produce the most voltage because it is used most commonly as a fruit battery. The next experiment that was done was testing each fruit with two screws and then two pennies. The lemon with the two screws had the highest voltage with V. The second highest voltage with the two screws was the orange with V and the next highest was the grapefruit with V when it had the two screws. The fruit with two screws that had the lowest voltage was the lime with a voltage of V. The orange had the highest voltage with the two pennies with a voltage of V. The second highest voltage with two pennies was the grapefruit with V and the next highest was the lime with V. The lowest voltage with the two pennies was the lemon with a voltage of V. MATERIALS AND METHODS In these experiments, lemons, limes, oranges, grapefruits, a multimeter, beakers, water, a zinc nail, a copper wire, and ph strips were used. The zinc nail and copper wire were poked into the grapefruit and then connected to the multimeter. The multimeter measured the voltage of the lemon. This method was continued with the orange, lemon and lime. The lime juice was squeezed into a beaker as the zinc nail and copper wire were put into the juice. The zinc nail and copper wire were connected to the multimeter which then measured the voltage. This method was continued with the lemon, orange and the grapefruit. A zinc nail and a copper wire were poked into an orange and were connected to a multimeter which then measured the voltage. The copper wire was then poked into another orange where the

4 Voltage Produced (V) zinc nail stayed in the one orange. Both the zinc nail and copper wire were connected to the multimeter which measured the voltage. This method was continued with the lemon and the lime. The lime juice was squeezed into the beaker as a ph strip was stuck into it. The ph strip then measured the acidity of the juice. Then the copper wire and the zinc nail were stuck into the juice and the ph was measured again. This method was continued with the lemon and the orange. Water was poured into a beaker as a ph strip was stuck into it. The ph strip measured the amount of acidity into the water. Ten drops of lemon juice were then added and the ph was measured again. This method was continued as twenty drops and then fifty drops of lemon juice were added to the water. RESULTS AND DISCUSSION Lemon Lime Orange Grapefruit Type of fruit Figure 1: Most voltage produced from citrus fruits The lemon and the grapefruit were found to produce the most voltage (both producing 0.76 V) out of the four citrus fruits that were tested. The lime was found to be the one with the least amount of voltage (producing 0.61 V). Overall, the lemon and the grapefruit probably produced the most voltage because it has a higher acidity than a lime or an orange. The more the acid in a fruit, the more voltage it produces. This is because the citric acid in a fruit is acts like the acid in a battery so the fruit can produce voltage.

5 Voltage produced (V) Lemon Lime Orange Grapefruit Type of juice Figure 2: Most voltage produced from fruit juice. The grapefruit juice was found to produce the most voltage (producing 0.72 V) out of the four types of fruit juices. The fruit juice with the least amount of voltage was the lemon (producing 0.64 V). This happened because the grapefruit juice didn t have a voltage that was that different from the grapefruit so the grapefruit s voltage was not affected when it was pure juice. The lemon juice on the other hand had a very different voltage than just the fruit. There were probably some more qualities that give the whole lemon more voltage than the voltage of the lemon juice.

6 Voltage produced (V) Two in one Lemon One in two Lemons Two in one Orange One in two Oranges Two in one Lime One in two Limes Fruit with two or one probe Figure 3: Voltage produced from citrus fruit with two probes in one or one probe in two fruits The two probes in one orange seemed to produce the most voltage (producing 0.67 V) and the lime with one probe in each of two fruits produced the least amount of voltage (producing V). Overall, having one probe in each of two of the same fruits did not produce a lot of voltage. This happened because there was not much of an electrical connection between the two fruits and two probes. The two probes in one fruit were what were normally done when the voltage was tested from a fruit. If the voltage had to be tested of two fruits, there would have to be two probes in each of the two fruits. There is a very clear result that putting the one probe into each of two fruits did not produce a lot of voltage because there was not a lot of electrical connection between the probes and the fruit.

7 acidity (ph) acidty (ph) lemon juice lemon juice with copper & zinc lime juice liquid lime juice orange juice orange juice with copper with copper &zinc &zinc Figure 4: Most acidity in fruit juice and fruit juice with copper and zinc It was found that the lemon is the most acidic of the three fruits (having a ph of 2). The orange is the least acidic (having a ph of 5). Putting the copper and zinc in did not change the acidity at all. Overall, the lemon was the most acidic because it is one of the more sour fruits. The lemon also has more citric acid than the lime or the orange. A fruit like the lemon has a lot of citric acid so its ph was lower. The lower the amount of acid the higher the ph is. A lime also has a lot of citric acid, but not as much citric acid as the lemon had water ten drops of lemon juice liquid twenty drops of lemon juice fifty drops of lemon juice Figure 5: Highest acidity when lemon juice is added to water

8 It was found that fifty drops of lemon juice in water had the most acidity (with a ph of 4) and water alone had the least amount of acidity (with a ph of 6). This happened because the lemon juice had the most citric acid. Putting lemon juice into water would make the water more acidic and make the ph level lower. The more lemon juice put into the water the more acidic the water became. The ph level got lower as more lemon juice was put into the water. When something is more acidic, the ph level gets lower. That was what was happening as the amount of lemon juice was increasing in the water. CONCLUSION The citrus fruits were tested to see how much voltage was produced. My hypothesis was correct because my hypothesis was that the lemon would produce the most voltage because it is most commonly used as a fruit battery. These results will be important to people when their power goes out and they can used some lemons to power a light bulb for light. A future experiment that could be done is testing other fruits that are not citrus fruits. CITATIONS Amount of Electricity Contained Inside Different Types of Citrus Fruits. Cascience6isp.wikispaces.com Jan Web. galvanometer." Britannica School. Encyclopædia Britannica, Inc., Web. 22 Jan Glencoe Science. Visualizing Voltmeters and Ammeters. Electricity and Magnetism. New York. Hila Science. Lemon Battery. hilaroad.com. 20 Jan Web. Holt, Rinehart and Winston. Electric Current and Electrical Energy. Electricity and Magnetism. Holt, Rinehart and Winston Print. HowStuffWorks.com Contributors. "What is voltage?" HowStuffWorks.com. 27 July Web. 15 January 2014.

9 Knight, Judson. Acids and Bases. Science of Everyday Things. Volume 1. Farmington Hills. Gale Group Print. McGraw-Hill Companies Inc Print. SearchCIO-Midmarket. Voltage. SearchCIO-Midmarket.com. Sep January Web