Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-L] [SPAM] Re: The Make-Believe World of Real World Physics




On 2013, Jul 30, , at 13:03, Paul Lulai <plulai@stanthony.k12.mn.us> wrote:


The 1wire 1 batteryb1 bulb lab is a great standard lab. It appears in many many programs (physics by inquiry, workshop physics, real time physics, modeling physics, hewitt, etc...) There is no trick. When done we make sure kids known the first time structure of a lamp, the need for a complete path in standard circuits, where there are conductors and insulators, that standard lamps do not have a preference for direction of flow, and more. Worth the time. Big payoff. Leads to many following concepts.


I pray much of this transfers when incandescents (soon) are museum items. Well, disassembly of a domestically powered LED is instructive.

Is it bad form to use hydraulic analogies? -- certainly less convenient!



On 2013, Jul 30, , at 03:07, jbellina <inquirybellina@comcast.net> wrote:

I'm going to come out of left field with this, if you know what I mean. I think there are at least two good reasons for starting with average velocity problems.


The first is that is all we really can experience in our lives. Instantaneous quantities are mathematical idealizations, and not directly in our experience. So if we want to begin concretely with our own experiences, there we are. Thinking it this why leads to a natural set of developmental questions when we know the velocity is indeed changing. Working with students to figure out how to do that gives a rationale for the development of kinematics.


My Prius' display gives actuel MPG (which is about as instantaneous as one may have w/o lab equipment) and a trip (averaged since the last time the reset switch pushed). Does not a speedometer give "instantaneous" speed. Average speed requires the collection of data and algebraic manipulation; unless ones GPS device does it.

I'm often surprise that my calculation of average speed over a long trip (just traveled 3k mile in ~ one week) is about 60mph while during most of the trip I've risked a confrontation w/ the local hwy patrol. Here's an appropriate calc. for students.

bc thinks he's French.