BEFORE: Have students sketch (on their own paper) a simple circuit with all three major components. Ask for three volunteers to draw their circuits on their whiteboard, show the class, and see if all students agree that what they have drawn is a complete circuit.
DURING: Pose the question - What is the relationship, if any, between the voltage difference and the current in a circuit?
Students should develop and carry out a procedure to measure voltage difference and current. They should keep one resistor in the circuit and change only the voltage difference or the current, then record the new data. It is at student/teacher discretion how many points of data to collect (6 is recommended). At the end of the experiment, they should have several points of data that include current and voltage difference for each point.
*BE SURE TO APPROVE THE STUDENTS' PROCEDURE BEFORE THEY PERFORM THE EXPERIMENT*
A sample procedure can be found in the attachment "Sample Student Report".
After the students collect the data, they should graph using the Logger Pro software and do a 4-step analysis of the graph.
1) Write the equation of a line
2) Replace X and Y with the experimental variables.
3) Replace m and b with their values from the graph.
4) Write the final equation (the mathematical relationship). Determine the significance of the slope by looking at what was held constant in the equation.
Assign students the post-lab questions (see lab sheet) to practice using Ohm's Law, which they will have just discovered.
AFTER: Have students present their results by writing their findings on the whiteboard or interactive whiteboard. All groups should present their graph and 4-step analysis. Each group should also have an assigned question from the worksheet to present. Students should present their graph and explain how the graph led them to the discovery of Ohm's Law. They should also work through their assigned problem. Allow other groups to ask the presenting group questions.