1. Voltage 012-11006 r1.04

2. The Snapshot button is used to capture the screen. The Journal is where snapshots are stored and viewed. The Share button is used to export or print your journal to turn in your work. Introduction Journals and Snapshots Note: You may want to take a snapshot of the first page of this lab as a cover page for your journal. Each page of this lab that contains the symbol should be inserted into your journal. After completing a lab page with the snapshot symbol, tap (in the upper right corner) to insert the page into your journal. Voltage

3. Lab Challenge Answer the question, "What is voltage and where does it come from?" Explore a fundamental form of an electric cell constructed from a piece of fruit. Voltage

4. Background The Volt is the unit of measurement used to describe the difference of electric potential energy between two objects (often called Voltage). A Volt is equivalent to the amount of electric potential energy that the voltage source gives to each coulomb of charge within it. Alessandro Giuseppe Antonio Anastasio Volta (1745-1827), developer of the first electric cell. 1 Volt = 1 Joule of energy 1 Coulomb of charge Voltage

5. ...Background A voltage source can be anything that converts some form of energy into electric energy. There are many voltage sources, including wind turbines (wind mills), photoelectric cells (solar panels), and electrochemical cells (batteries). Voltage

6. ...Background Electrochemical cells convert chemical energy into electric energy. They have 2 electrodes (usually 2 types of metal) and an electrolyte (usually a chemical solution such as copper sulfate, salt water, or fruit juice). The chemicals in the electrolyte work to decrease the number of negative charges on one electrode and decrease the number of positive charges on the other electrode. As the work is done to remove charges, chemical energy is converted to electric potential energy. One electrode has unbalanced positive charges. One electrode has unbalanced negative charges. Voltage

7. Self-Check Q1: What happens to two "like" charges (positive and positive, or negative and negative) when they are near each other? Hint: "like" poles on a magnet do the same thing. or Voltage

8. Self-Check Q2: As the electrolytic solution decreases the number of positive charges on one of the metal electrodes, is the number of negative charges changing on that same electrode? Is that electrode now positively charged or negatively charged? Voltage

9. ...Background Because of the net charge imbalance created by the chemicals, the electrochemical cell becomes a voltage source similar to a battery. As more charge is taken from each electrode the electric potential (voltage) increases. In 1800 Alessandro Volta invented the first battery made from electrochemical cells composed of copper and zinc disks (the electrodes) separated by pasteboard (thick paper) soaked in salt water or vinegar (the electrolyte). Voltage

10. Self-Check Q3: Two pieces of metal, one with only positive charges on it and the other with only negative charges on it, are electrically connected. How do the charges react (both positive and negative)? Would they move, and if so which direction would they move? Voltage

11. Materials and Equipment Collect all of these materials before beginning the lab. Voltage sensor with leads Zinc-coated nail (galvanized nail) Piece of copper (bare copper wire) 2 different pieces of fruit Alligator clips D-cell battery Voltage

12. The steps to the left are part of the procedure for this lab activity. They are not in the right order. Determine the correct sequence of the steps, then take a snapshot of this page. Sequencing Challenge A. Record the voltage produced by a second piece of fruit to compare to the first. B. Insert the copper and the zinc electrodes into your piece of fruit. C. Ensure the copper and zinc electrodes are clean and free of corrosion. D. Record the voltage value. Voltage

13. Setup: Fruit #1 1.Connect your voltage sensor to the SPARK Science Learning System. 2.Mount the red and black alligator clips on the voltage sensor's 4 mm banana connector leads as shown below. 3.Choose the first piece of fruit then push the copper wire and the zinc-coated nail into the fruit about 5 cm apart. Leave about 2 cm of each electrode exposed. Voltage

14. 4.Connect the red alligator clip to the copper wire. 5.Connect the black alligator clip to the zinc-coated nail. Voltage Setup: Fruit #1

15. Collect Data: Fruit #1 1.Tap to begin collecting data. 2.Watch the value that appears in the digits display to the right. When that value has stabilized, tap to stop data collection. 3.Record the type of fruit you used and the stabilized voltage value from the digits display into the text box to the right. Voltage

16. Collect Data: Fruit #1 Q4: In the next step you will repeat the same data collection using your second piece of fruit. Will the voltage will be higher, lower, or the same? Justify your answer. Voltage

17. Setup: Fruit #2 1.Remove the nail and copper wire from your fruit with the alligator clips still attached. 2.Using the same technique as the first piece of fruit, insert the nail and copper wire into your second piece of fruit with the electrodes spaced ~5 cm apart with ~2 cm of exposed metal on each electrode. Voltage

18. 1.Tap to begin collecting data. 2.Watch the value that appears in the digits display to the right. When that value has stabilized, tap to stop data collection. 3.Record the type of fruit you used and the stabilized voltage value from the digits display into the text box to the right. Reminder: Don't forget to snapshot this page. Collect Data: Fruit #2 Voltage

19. Prediction Q5: In the next step you will measure the voltage from a battery. Will the voltage from the battery be higher or lower than the fruit? How much higher or lower will it be and why? Voltage

20. Setup: D-Cell Battery 1.Remove the alligator clips from the banana plugs. 2.Hold the red banana plug against the "+" end of the D-Cell battery. 3.Hold the black banana plug against the "-" end of the D-Cell battery. 4.The voltage probe will measure the voltage difference between the positive and the negative ends of the D-Cell battery. Voltage

21. Collect Data: D-Cell Battery 1.Tap to begin collecting data. 2.Watch the value that appears in the digits display to the right. When that value has stabilized, tap to stop data collection. Reminder: Don't forget to snapshot this page. Voltage

22. Analysis 1.How does the voltage of the first piece of fruit compare to the voltage of the second piece of fruit? (Check your Journal if you need to review your voltages.) Why do you think they are different/similar? Voltage

23. Analysis 2.How does the voltage of either piece of fruit compare to the voltage of the D-Cell battery? (Check your Journal if you need to review your voltages.) Why do you think they are different/similar? Voltage

24. Analysis 3.What is one thing that might increase the voltage from the piece of fruit? Voltage

25. Analysis 4.Could you light the bulb from a flashlight with the voltage of a piece of fruit? Why or why not? Voltage

26. Synthesis 1.Although an electrochemical cell made from a piece of fruit may supply a sufficient voltage to power some small electrical devices, its total charge on each electrode and the rate at which the net charge is produced is not sufficient to produce a proper current for these devices. What is one way to fix this problem using several electrochemical cells? Voltage

27. Synthesis 2.What would happen to the voltage measurement from your fruit battery if the two electrodes accidentally touched each other? Justify your answer. Voltage

28. Multiple Choice Question 1.What are two key parts of any electrochemical cell? a)copper and zinc b)electrodes and electrolyte c)fruit juice and copper sulfate d) Unknown Voltage

29. Multiple Choice Question 2.If you measured the voltage across two pieces of metal, and that voltage was zero, which of the following statements is true? a)Each piece of metal has zero charges on it. b)There are more positive charges on one piece of metal than the other. c)Each piece of metal has the same net charge on it. d)There are more negative charges on one piece of metal than the other. Voltage

30. Multiple Choice Question 3.If you connected the electrodes from two identical fruit batteries together (zinc to zinc and copper to copper), the voltage would: a)be twice as much as one fruit battery. b)be half as much as one fruit battery. c)be zero. d)be the same as one fruit battery. Voltage

31. You have completed the lab. Congratulations! Please remember to follow your teacher's instructions for cleaning-up and submitting your lab. Voltage

32. ALL IMAGES WERE TAKEN FROM PASCO DOCUMENTATION, PUBLIC DOMAIN CLIP ART, OR WIKIMEDIA FOUNDATION COMMONS: http://commons.wikimedia.org/wiki/File:High_voltage_warning.svg http://commons.wikimedia.org/wiki/File:Lemon_battery.png http://commons.wikimedia.org/wiki/File:Bettoni,_Nicol%C3%B2_(1770-1842)_-_Volta,_Alessandro_(1745-1827).jpg http://commons.wikimedia.org/wiki/File:ThermodynamicVSPhotovoltaicpanels.jpg http://commons.wikimedia.org/wiki/File:Batteries.jpg http://commons.wikimedia.org/wiki/File:Voltaic_pile_battery.png http://commons.wikimedia.org/wiki/File:M%C3%B6bius_resistor.svg http://www.pdclipart.org: lemon 2; lightbulb dramatic; pineapple; nail large head; http://www.freeclipartnow.com/office/paper-shredder.jpg.html http://commons.wikimedia.org/wiki/File:Greenpark_wind_turbine_arp.jpg http://freeclipartnow.com/science/energy/batteries/battery.jpg.html References Voltage