Webquest:  Ohm's Law

Answer these questions on your own paper or in a Word document.

  1. What is resistance?
  2. What causes resistance?
  3. Online experiment
    1. Open the Java Applet.
    2. For five different voltages, record the current in the circuit (milliamp meter).  Do not change the resistance.  Record the value of the resistance in Ohms.
    3. Using this Excel spreadsheet, create a graph of voltage vs. current.  Put the voltages on the y-axis and the currents on the x-axis.
    4. Use a trendline to determine the slope of the line.  To make a trendline, highlight click on the blue diamonds on your graph, then reight click.  Select add trendline, and on the options tab, select display equation.
    5. Repeat steps b, c, and d for 3 different resistances.
    6. What observations can you make about the slope of each line?
  4. What units is resistance measured in?  How is this unit defined?
  5. What unit is appropriate for the slope of the lines in your experiment? 
    1. How do you know this? 
    2. How does your slope compare to the quantity in your experiment with the same units?
  6. What is Ohm's Law?  Look up Ohm's Law on page 612 of your textbook or at this website.  Do your results support Ohm's Law?  Explain why or why not using your data.
  7. What factors affect electrical resistance?  Find four factors that affect electrical resistance and describe how each one affects resistance.  Hint:  three are related to size and shape, and one is related to the material.
  8. What is the purpose of a resistor in a circuit?  What are we trying to control in the various circuit elements for different devices?
    Made 22 February 2007
    by Lori Andersen.