Comments on: Dissent Of The Day: Mike Manganello

By: Olga

Olga — Tue, 21 Dec 2010 14:44:46 +0000

A couple of things: how come there is nothing about the lunar eclipse yet?
Second, @ JenW, a great extension (into other disciplines as well) may be, if the fuel gauge is more of convenience, what gauges are a must? Which gauges would you have if you only could have 5 on your dashboard?
And finally, is anyone doing anything about delicious bookmarks? Are we just hoping that the service would just change hands and we would keep on using it?

By: dy/dan » Blog Archive » [WCYDWT] Car Talk, Ctd.

dy/dan » Blog Archive » [WCYDWT] Car Talk, Ctd. — Wed, 15 Dec 2010 22:26:22 +0000

[…] Alex Eckert: I don’t feel that my presentation of the problem did anything to make it any more interesting for the students. I think what interested my students was them doing the following: 1) discovering on their own that it’s not 5 inches, 2) each taking a guess at what the actual length was, 3) understanding that THEY could figure out if their guess was correct or not. […]

By: Neil Stephenson

Neil Stephenson — Wed, 15 Dec 2010 21:58:05 +0000

#3) reminds me that the discipline (Social Studies for me) needs to set the benchmarks for success – not the teacher.

By: Alex Eckert

Alex Eckert — Wed, 15 Dec 2010 21:37:01 +0000

I don’t feel that my presentation of the problem did anything to make it any more interesting for the students. I think what interested my students was them doing the following:

1) discovering on their own that it’s not 5 inches
2) each taking a guess at what the actual length was
3) understanding that THEY could figure out if their guess was correct or not

By: JenW

JenW — Wed, 15 Dec 2010 15:42:35 +0000

I guess this essentially echoes what James McKee said @5, but this question wasn’t a “puzzler” to begin with. Some trucker really called in and asked the question. Tom and Ray didn’t know the answer right away, though they spent a few minutes working on it, and I believe asked listeners to help out. It’s been a good 10 years since the original call, so I don’t remember for sure. Unfortunately, it’s also before the days of “PodCasts” and the like, so they may not have easily accessible archives of the show.

Also, fixing fuel gauges is ridiculously expensive, for something that’s essentially a convenience rather than an actual operating necessity. Often, by the time a fuel gauge breaks, the cost of replacing it is more than what the car is currently worth. I guess I don’t know that the same is necessarily true for trucks, but I’ll go ahead and assume it is. :)

By: Carl Malartre

Carl Malartre — Wed, 15 Dec 2010 15:35:54 +0000

Mike said: ” Personally, I find the Car Talk problem kind of boring (…)”

I’m with him on that. Depending on who you are, some things may or may not interest you. Gilbert’s explanation also sounds true. Depending on how the story is told and by who, you could become interested in the problem.

If he was a truck driver living before gauge were invented, maybe the story would sound more useful.

At the same time, solving stuff is just fun enough.

Carl

By: James McKee

James McKee — Wed, 15 Dec 2010 15:20:12 +0000

As an aside, why might fuel gauges in this context be inaccurate? It should be plain to students after messing with this problem for a while why a typical, float-type fuel gauge might be inaccurate, and how it is inaccurate (for what readings is the fuel gauge close, for what readings is it “off,” and is it reading high or low?) How could we design a fuel gauge that is accurate?

By: James McKee

James McKee — Wed, 15 Dec 2010 15:16:51 +0000

I have to disagree that this is pseudocontext under the argument that (as I posted on the original CarTalk thread) that a trucker actually came to me with this problem a couple of years ago. He wanted a dipstick method that would give him more accurate fuel readings than his fuel gauge (I guess they’re universally inaccurate?).

If a member of a profession brings you a real-life problem from their “world,” I think that has to disqualify the problem from being labeled pseudocontext.

By: Jerzy

Jerzy — Wed, 15 Dec 2010 15:13:31 +0000

“An arbitrary number maybe (why not one fifth of a tank?) but not irrelevant.”

Woo, there’s an extension to the problem: how little gas can still be left in the tank before the trucker really needs to start looking for a place to refuel?

Have the kids research or guesstimate how much gas such trucks can hold, how many miles per gallon these trucks get, and what the typical distance is between gas stations.
Try it with “typical” numbers and compare to “worst-case scenario” numbers (low MPG going uphill, and out in the boonies where gas stations are far apart).
Then maybe it’ll be clear that it’s safe to wait for refueling until you’re down to (for example) 1/5th of the tank, but (say) 1/8th would put you at risk of running out of gas before you reach the next station.

By: Andrew

Andrew — Wed, 15 Dec 2010 15:00:51 +0000

“In both of these cases, I deferred to the authority of the radio hosts. If either of Mike’s complaints were valid, why wouldn’t the hosts have echoed them?”

I think this a misreading of CarTalk as both an automotive and educational institution. CarTalk Puzzlers are often classic math problems lightly wrapped in automotive context, or flat out logic puzzles.

http://www.cartalk.com/content/puzzler/2008.html

It’s a good show, but the place to look for authentic questions is in listener calls and questions, rather than the puzzler.