Re: [Phys-l] Any teaching tips

[Marty Weiss <martweiss@comcast.net>]

On Jan 29, 2011, at 11:21 PM, Jack Uretsky wrote:

> Sounds like a communications problem,  To the uninitiated mind, "known" 
> and "unknowns" have nothing to do with units.  Maybe you're taking too big 
> a logical step.  Try putting the dialogeue at an infant level:  "What do I 
> want you to tell me ?"
	That works.  It's similar to what I still do in the small school now, and what I did in the large school before this.    We usually read a sample problem out loud.  Then I say,  "What do you know?  Write the facts down."   They can write them as phrases or sentences.  Such as:  we know the speed in the beginning is zero.  We know the speed at the end is  xxx m/s   We know the time is  yyyyy sec.    (I have already gone over what m/s means
Then:   "What are they asking you to find?"    They might write:  they want us to find the acceleration.    At first I might ask them what acceleration means and we might have a discussion on what that means and how you tell acceleration from speed and the difference between speed and velocity.   
Then the kicker:  "Go to the equation list and answer this question:   "What equation has the facts you know and the fact they want you to find, and NO MORE!"  That's the key.  If we must do plug and chug a lot, then this last question is what they have to get down pat before going on.  
After a few problems doing this they can wean out of writing sentences and then you can teach the equal sign and symbols for things, such as Vi = 0 Vf = xxx m/s and so on.   
Crawl before walking, walk before running.  

	Granted, none of us want to have a course with all plug and chug problem solving.  But, that's the facts of life in a typical non-honors/AP physics class and with most, if not all, of the "usual suspect textbooks we must use, and many times even in a top level physics course.  Most of our students don't come from a background of knowing how to interpret problems right out of the box and they have to be taught how to read and interpret a problem.   Math doesn't do it.  The English prose here is not the same as reading a story in English class or Social Studies.   As many have written here, we often have to teach the algebra along with the physics also, and the typical physics reading process is different and strange to them.  

	Usually the problems would be built around a lab with racing cars or PASCO cars on their track with some timers.  Build things, Use stuff from Home Depot and WalMart.   Go to the local lumber yard and ask for scrap wood... build ramps, tracks, and anything else you can think of to do neat labs.  We must try to come up with new, different, and exciting labs to do that will teach as close to reality as possible and get the point across of how to figure out what to do, what to write down as data, and how to figure it all out.   Make the class so that the labs are built around the problems and the problems are not all ho-hum theory.  Look up things like braking distances of real cars, real reaction times, real jet plane velocities, real fast-ball pitching times, etc.  use toy cars if you must... buy some track and field timers at WalMart or Dick's Sporting Goods.  Do things that are interesting.  In warm weather, go outside or in the halls and drag things, race your little cars down a long hall with the timers.  We even raced our storage pushcarts loaded down with bricks to measure friction.  The assistant principal even took part and used it as the teaching observation for the semester.  The kids thought it was neat to see a middle-aged woman racing alongside a pushcart with a timer in her hand, wearing a tight skirt and heels!    After the first few labs have the class devise the data charts they need.  Then after they learn how to do this you can have them write up the lab procedure themselves (after we discuss what the equipment is and what we will try to do.)  I don't care if there is a large percent error for the first few labs such as this.  Make your class exciting and memorable.   

	I guarantee if you take the time to teach them how to read, write, and do they will remember physics for a long time.  

MW.