| Series batteriesPARTS AND MATERIALS  
                      
                      Two 6-volt batteries 
                      One 9-volt battery  Actually, any size batteries will suffice 
                    for this experiment, but it is recommended to have at least 
                    two different voltages available to make it more 
                    interesting.    CROSS-REFERENCES  Lessons In Electric Circuits, Volume 
                    1, chapter 5: "Series and Parallel Circuits"  Lessons In Electric Circuits, Volume 
                    1, chapter 11: "Batteries and Power Systems"    LEARNING OBJECTIVES  
 
 SCHEMATIC DIAGRAM  
                      
 
 ILLUSTRATION  
                      
 
 INSTRUCTIONS  Connecting components in series means 
                    to connect them in-line with each other, so that there is 
                    but a single path for electrons to flow through them all. If 
                    you connect batteries so that the positive of one connects 
                    to the negative of the other, you will find that their 
                    respective voltages add. Measure the voltage across each 
                    battery individually as they are connected, then measure the 
                    total voltage across them both, like this:  
                      Try connecting batteries of different sizes 
                    in series with each other, for instance a 6-volt battery 
                    with a 9-volt battery. What is the total voltage in this 
                    case? Try reversing the terminal connections of just one of 
                    these batteries, so that they are opposing each other like 
                    this:  
                      How does the total voltage compare in this 
                    situation to the previous one with both batteries "aiding?" 
                    Note the polarity of the total voltage as indicated by the 
                    voltmeter indication and test probe orientation. Remember, 
                    if the meter's digital indication is a positive number, the 
                    red probe is positive (+) and the black probe negative (-); 
                    if the indication is a negative number, the polarity is 
                    "backward" (red=negative, black=positive). Analog meters 
                    simply will not read properly if reverse-connected, because 
                    the needle tries to move the wrong direction (left instead 
                    of right). Can you predict what the overall voltage polarity 
                    will be, knowing the polarities of the individual batteries 
                    and their respective strengths? 
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