Phet colorado circuit construction kit

PART I - Current, Electrical Potential and Resistance

· Download the following file, to your desktop by:

· right-clicking on M3-Activity-1 : File attached

· selecting Save target as...

· saving the file to your computer where you can easily access it again

This file will be used within the lab simulation.

Start the simulation "Circuit Construction Kit (DC Only) " (if you haven't done so already) by clicking on the image below. : http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-dc_en.jnlp

The simulation has a set of controls on the right hand side of the screen. These are divided vertically into different areas. Make the selections indicated.

· From "Circuit," select load.

· When prompted, upload the file M3-Activity-1.

· From "Visual," select "Life Like."

· From "Tools," select noncontact ammeter.

· Position the voltmeter and ammeter as shown in the image below.

http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-dc_en.jnlp

Image retrieved from the PHET “Circuit Construction Kit (DC Only)” simulation.

Inside your notebook, draw a graph with potential (V) on the vertical axis and current (I) on the horizontal axis. Use Ohm's Law to make a numerical prediction of the shape that this graph will take. The default values are 9.0 V for the battery, and 10.0 Ohms for the resistor, but you will want to right click on both components to verify this. Plot at least 5 prediction points, and sketch in the graph in your notebook. Now use the Circuit Construction Kit to measure the relationship between battery potential and current.

· Leave the resistor value constant.

· Record the battery voltage and the resulting current in the circuit for the default values.

· Right click on the battery, and change the voltage.

· Click on the "Run" arrow to start the simulation.

· Record the new values of potential and current.

· Take at least 5 data points.

How does the graph produced through your simulation data compare to the predicted graph in your notebook? Continue your investigation. Can you find any factors that might explain any discrepancies? Try turning on the voltmeter and measuring the battery terminal voltage as shown below. Does the battery terminal voltage match the voltage you set using the simulation controls?

Describe in detail any changes that need to be made to the procedure in order to make the predicted graph, so that it will reflect results of the simulation. Use your revised procedure, and place both graphs in your lab report. Be sure to provide a discussion of the differences between a real source of EMF V.S. and an ideal source of EMF.

Part II - Kirchhoff's Rules for Current and Potential

Your basic mathematical tools for analyzing a circuit are Ohm's Law, and Kirchoff's loop rule for potentials and junction rule for currents. We are going to use this activity to gain confidence in the accuracy of these latter two rules, and also to give you some practice in applying these rules.

· Download the following file, to your desktop by:

· right-clicking on M3-Activity-2 : File attached

· selecting Save target as...

· saving the file to your computer where you can easily access it again

· Load the circuit file M3-Activity2 (as you did for M3-Activity1 in Part I).

· Activate the voltmeter.

When the simulation starts, the switch in the circuit is open. There is no conductive path, so the far right left branch of the circuit is not active. Initially, we will only concern ourselves with the portion of the circuit containing batteries and the middle branch.

The loop rule states that the sum of changes in voltage around any closed path in a circuit is zero. In this activity, you are going to use the voltmeter to follow a closed path in the circuit provided. You will record the change in voltage across every component, and then take the sum of these changes.

· Draw the circuit in your laboratory notebook.

· Draw arrows to indicate a sense of direction through the circuit.

· Traverse the loop of the circuit with the voltmeter, measuring the change in potential across each component.