Brand New Week

Honors Physics exercised their brains with their light (not lite) exam. Tomorrow, we’ll begin discussing electric charge and the forces that charged particles can generate.

Physical Science B reviewed the concept and math behind series circuits and then turned attention to parallel circuits. Series circuits offer only one option for charged particle travel; parallel circuits offer multiple possible paths that form complete circuits. For parallel circuits, the failure of one pathway does not stop charges from using the other paths to travel to and from the power supply. However, by adding more options, this actually lowers the resistance of the circuit. More devices hooked in parallel to a single power source means more current flowing through the circuit. More current, more resistance heating. This is how overloading a circuit in your home can lead to a fire. We worked practice problems quantifying resistance, voltage and current for parallel circuits and will discussing electric power and safety tomorrow.

Physical Science E reviewed their Ohm’s Law lab and folks’ data looked good. It was pretty clear that comparing the voltage provided and current produced through a single circuit gave the same value, and that corresponds with Ohm’s Law: R = V/I. Graphing voltage versus current gave very linear patterns with the slope of the resulting line falling within the tolerance limit for the given resistor. For the non-ohmic light bulb, current increased at a more rapid rate at the low voltages, but slowed its increase at higher voltages. This is why light bulbs burn out when you turn them on. The current coming through is high and the friction does a number on the aged filament. We didn’t have time for any more, since the assembly ran long. Tomorrow, we’ll delve more deeply into series circuits and then turn attention towards parallel arrangements.

Physics F and G Blocks reviewed for their exam on light, reflection and refraction. We walked through the chapter highlighting relevant material and making note of sections that we didn’t cover in much depth. You’ve seen the formula sheet many times, but may not have noticed that sign conventions are not presented. You need to have those fixed in your heads in order to successfully work the optics problems.

Homework

Honors Physics A: Read 17.1 and complete Chapter Review items #1-10
Physical Science B: Read 16.3 and complete the 16.3 Section Review and the Practice on pg. 551
Physical Science E: None
Physics F and G: Study for exam