Fundamentals of Circuits I: Current Models, Batteries & Bulbs

Fundamentals of Circuits I: Current Models, Batteries & Bulbs v 0.1
Question 1.13 What did you feel
when there is a current through it
Besides giving off light, what happens to the bulb
Question 1.14 What can you say about the path needed by the current to make the bulb
glow Your explanation should be based on the observations you have made so far.
Model A
Next we explore and contrast some competing models for current in a circuit. Consider
a circuit equivalent to the one shown in Fig. 5 with the switch closed. Fig. 6 depicts
four different models for current in this circuit. These models are based on models that
students often propose. These models are described below.
1
Model B
1
2
2
Model C
1
Model D
1
2
2
Figure 6: Four possible models for current.
Model A: Current flows from the positive terminal of the battery through wire #1 and into the
bulb. The bulb uses up all of the current and no current flows back to the battery
in wire #2.
Model B: Currents flow from both terminals of the into the bulb.
Model C: The current flows from the positive terminal of the battery into the bulb. The bulb
uses up some of the current and a smaller current returns to the negative terminal
of the battery.
Model D: A Current flows from the positive terminal of the battery into the bulb, and the
exact same current returns to the negative terminal of the battery.
PHYS-204: Physics II Laboratory 8