On Feb 4, 2011, at 23:11, Craig <diese...@pisquared.net> wrote:
> On Fri, 4 Feb 2011 22:27:02 -0500 John Reames <jwrea...@comcast.net>
> wrote:
>> It isn't like the workbooks don't come close to it (" __ + 3 = 5 " is
>> identical to "x+3=5; solve for x", except people make a bigger fuss
>> about the latter being more complex because you can't add or subtract
>> letters to/from things (which isn't strictly true even in bases less
>> than 10))
>
> Does he work the " __ + 3 = 5 " kind of problem already? If so, "Here is
> a number we don't know, but rather than call it, 'The Number We Don't
> Know,' how about we call it something? What do you think? You know, we
> cannot call it by another number, since we don't know what its value is
> yet. How about we call it by a letter? How about the letter 'x'? Once we
> call it 'x', maybe we can trick it into telling us what it is ... "
That's exactly my point, and the kind of thing that I have in mind... (I've
also been slipping in some things like "Isn't 13+14 the same as 13+4+10?"...
mainly as a way of speeding up mental arithmetic)
>> He's no flat-earther, although I haven't been able to show him
>> experimentally that the earth is round... I guess we could go for a
>> field trip, and go across the lake pontchartrain causeway, abusing a
>> gps for elevation...
>
> At 24 miles across, it will be more than enough to show him that things
> disappear over the horizon. You could introduce him to the concept that
> water tends to form a constant-height surface ("sea level"),
Yep, that is exactly WHY I would use that as an example... It's just a little
far from Baltimore.
He has figured out that water will be "flat", and he also has noticed that the
level of the water is independent of the edges of the container it is in (a cup
that isn't held just right will spill in one place only)
I've also shown him that if you carefully fill a level container with water,
you can have the water go above the top of the container without spilling.
Speaking of physics experiments, when bleeding the (clear) plastic fuel lines
in one of the OM606, I noticed that it was it difficult to tell whether a line
was completely filled with air or completely filled with fuel (since they turn
yellow/brown with age). What I ended up doing is shining a laser pointer
through the line at an angle; if the line were filled with air, the beam would
not be (significantly) refracted, but if fuel was in the line... Refraction!
_______________________________________
http://www.okiebenz.com
For new and used parts go to www.okiebenz.com
To search list archives http://www.okiebenz.com/archive/
To Unsubscribe or change delivery options go to:
http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
