“ Battery-Resistor”: Check “ show battery” and “ show cores”, watch what happens, adjust some variables

1. Why do electrons (blue dots) move? Draw a diagram of the battery, label the flow of electrons. The flow of current (+) is opposite; draw this and note if toward or away from + terminal of the battery.

The electrons are moving because of the voltage of the battery. Away from +terminal.

2. What does the Ammeter (on the left) measure? How is this shown in the sim? An ammeter measures amperes or flow of current 3. What role do the “ green dots” in the resistor play in the sim? What do you think they represent? What does this tell you about the effect of resistors in a circuit? They are putting resistance on the electrons flowing through. The electrons move faster when the resistance is turned down, and the battery becomes increasingly hot.

4. Increase the resistance (# green dots). What affect does this have on temperature? WHY? It lowers the temperature because when the resistance is down, there are positive amps going back into the battery causing it to overheat. When the resistance is higher, there are less amps going in. which decreases the temp.

5. When the circuit gets hotter, what affect does this have on current? Explain using kinetic-molecular theory. The electrons become bundled up, leaving spaces between them. It also increases their speed.

6. To make the circuit “ cold”, what do you need to do? WHY? Turn the resistance up and the voltage down. It completely stops the flow of electrons through the battery. Which means the battery is not able to work because there is no electric current being created.

7. Describe the relationship between voltage and temperature. The higher the voltage, the higher the temperature. The lower the voltage, the lower the temperature.

“ Resistance in a Wire”: 1. In this sim, what variables are you seeing the relationship of. Write the formula below, and indicate the units used to measure each one. Resistance : R= V/I Current, resistance, and voltage. Voltage: V= I x R Current, resistance, and voltage.

2. Try increasing the resistivity of the resistor, ρ. How does this change the “ look” of the resistor? Describe how that relates to the formula you just wrote (direct, indirect relationships, etc.). What happens to the value of “ R” (Resistance)? Is this something that can be changed in a resistor that you would buy in a store to use in a circuit? The resistor become dark red and the balls are in a straight line not moving. Considering there is no current, I do not see how the value of R can be calculated.

2. If you increase the length (L) what happens to “ R”? WHY? R will increase as well. The more is the length of the sample there are more number of scatterers in the direction electron moves to, larger resistance.

4. If you increase the area (A) of the resistor. What changes? WHY? If the cross section is large, a large number of electrons can move Parallel to cause current, and as current is total sum of charge flowing per second, it make easy to get large current for a given voltage, hence less resistance. So R is inversely proportional to A.

5. Write a summary about the different relationships you looked at in the properties and measurements of a resistor. I learned that you will need a current, voltage and resistance to get the value of a resistor. I also learned that resistance is very important, especially when it comes to temperature. The resistance will determine whether or not the batter is cold or hot and can determine if the batter will work or even have an electrical current.