Objectives:

• 1. Use Logger Pro Software, Voltage, and Current Sensors, and assemble an electric circuit
• 2. Students Will Be Able To (SWBAT) distinguish between Voltage, Current, and Resistance
• 3. SWBAT Use Ohm's law to calculate Voltage, Current, and Resistance
• 4. SWBAT define a "short circuit"

Materials:

Batteries, Battery Holsters, and Metal-with Four Prongs on the Side.

Lab Purpose:

• 1. Measure voltage and current and calculate the resistance in an electrical circuit.

Lab Procedure

Safety Considerations: The voltages and currents in this lab are safe to touch, but care should be taken to assure that clips and exposed wires do not touch each other to create a short circuit. This could damage the Logger Pro sensors.

• 1. Connect the Voltage and Current Probes to the Logger Pro interface.
• 2. Connect the Logger Pro interface to power and to the Lap Top Computer.
• 3. Open a Logger Pro Window on the Lap Top and set up the table and graph as follows:
• a. Under "Data", select "New Calculated Column".
• i. Name: Resistance
• ii. Short Name: R
• iii. Units: Ohms
• iv. Equation: From the variables (columns) tab select "potential. Then type the division slash. Then select Current from the variables (columns) tab.
• v. Under the "Options" tab, select "Displayed Precision" = 0
• vi. Click "Done"
• b. Adjust the width of each column so each of the 4 columns is visible simultaneously.
• c. Select the "Experiment" tab, then "Data Collection"
• i. From the "Mode" drop down arrow, select "Events with Entry"
• ii. Click "Done"
• d. Click on then delete the Current vs Time graph.
• e. On the remaining graph,
• i. Double click on the X-Axis name (Time), and select Current.
• ii. Change the Potential Axis Scale to read from "0" to "7"
• iii. Change the Current Axis Scale to read from "0" to "0.07"
• iv. Under the "Option" tab, select "Graph Options". Then disable "Connect Points"
• 4. Assemble the components as shown in Figure 1. Note that there will be four different battery assemblies: One 1 ½ volt battery, two 1 ½ volt batteries, three 1 ½ volt batteries, and four 1 ½ volt batteries. EACH group member will assemble one of the test configurations. EACH group member will operate the Logger Pro data collection for one of the configurations. To begin, select any one of the four battery configurations.

Figure 1 Electric Current Test Set Up

• 5. Once the above set up is complete, under the experiment tab, click "Keep"
• 6. Move the clip at point A to the bottom of another resistor (R2). Click "Keep"
• 7. Repeat step 6 for the other 2 resistors.
• 8. Remove the initial battery configuration and install a different battery configuration.
• 9. Repeat steps 5-7.
• 10. Remove this second battery configuration and install the final battery configuration.
• 11. Repeat steps 5-7.
• 12. Remove this third battery configuration and install the final battery configuration.
• 13. Repeat steps 5-7.
• 14. Save the Logger Pro screen to the Electric Current Lab folder in the Physics Folder on your Lap Top Desktop.
• 15. Assure that the "Objectives" for this activity were achieved for EACH member of the group. Also, EACH group member knows how to accomplish the lab report requirements.
• 16. Additional experimentation is allowed as time permits.

Data and Data Analysis:

This graph shows that the potential always stayed the same during a four dot period. The current changed in everyone, so the straight lines show how the current is connected to the potential.

Conclusion:

• 1. The purpose was accomplished. Students measured the current and then calculated the resistance. The students believe that the purpose was accomplished for their group.
• 2. If the voltage is doubled or halved, but the resistance stays the same then the graph will look totally different. If you double the resistance than the current will also change, the same if you halved the resistance. The current will change if you double or halve the voltage

Debs DeAngelis

http://www.onlinewfh.com