The Irascible ProfessorSM

Irreverent Commentary on the State of Education in America Today

by Dr. Mark H. Shapiro
"No amount of learning can cure stupidity, and higher education positively fortifies it"   .....Stephen Vizinczey, An Innocent Millionaire, (University of Chicago Press, 1983)

Commentary of the Day - November 5, 1999:

Guest Commentary by Arlyn DeBruyckere - The ETS is Always Right:

(A note from the Irascible Professor for those whose knowledge of physics is limited... weight is the gravitational force on an object near the surface of the earth, moon or other planetary object, while mass can be thought of as the amount of "stuff" in some object.  For example, a can of peas will weigh much less on the moon than it does on the earth, but it still has the same mass.)

A few weeks ago on... (the PHYS-L mailing list) we were discussing weight and another member posted a test question on the recent PSAT Test.


(a) ounce : pound
(b) gram : weight
(c) container : liquid
(d) size : height
(e) boundary : periphery

I wrote a letter to the Educational Testing Service to complain about the question.  I wrote:  "The correct answer is none of the above, but I'm afraid (even saddened and angry) that you will count the correct answer as (b).  A gram is not a unit of weight but a unit of mass, something that I strive on a daily basis to get my students to understand.  A question like this on the PSAT only demonstrates why US students have so many problems on international tests.

It is true that the answer (b) is the only choice of units : quantity but it also reinforces a misconception that is common in our society and creates huge barriers to understanding physics and chemistry."

Today I received a response:

Dear Ms. DeBruyckere (the first mistake - my wife doesn't like me being called Ms):

    As one of the assessment specialists responsible for the verbal sections of the PSAT/NMSQT, I am writing in response to your inquiry regarding an analogy question in the test administered on October 12, 1999.

    The capitalized terms of the analogy are "METER:DISTANCE"; the relationship between these terms can be stated as "The 1st is a unit that may be used to quantify a 2nd."  Of the five choices offered, only (B), "gram:weight," displays a relationship similar to that of the of the capitalized terms.  While it is true, from a strictly scientific point of view, that a gram is a unit of mass and not of weight per se, in common, everyday use grams are often thought of as units of weight.  For example, on the nutrition facts label on a certain can of tuna the serving size is said to be "1 can (2.8oz/78g)"; the weight of a certain chocolate bar is given as "3.5 oz/100g."  Merriam Webster's Collegiate Dictionary (Tenth Edition) gives as a second definition of gram "the weight of a gram under standard gravity."  In many "real world" situations, ounces and grams, as well as pounds and kilograms, are used interchangeably to quantify weight.  This practice is reflected in the standard conversion tables that give the U.S. equivalents of metric units: a gram is said to be equivalent to approximately 0.035 ounce (and ounces, of course, are units of weight).

    Again, it is indisputable that for a scientist, especially a physicist, a gram is a unit of mass; an object with mass does not have weight until acted on by a gravitational force.  The context of the analogy, however, makes it evident to both the scientifically literate and those familiar only with the more common, if less precise, sense of the work that (B) is the only possible answer here.  It should be noted, also that in both the test itself and the descriptive material published by the College Board (the PSAT/NMSQT Student Bulletin) test takers are advised to select the best of the choices offered; in this particular case, that choice is (B).  This question was one of the easiest on the test:  nearly 90% of the students selected (B) as the best answer.  Because the test administered on October 12 will be disclosed to students, no question in it will be used in future versions of the PSAT/NMSQT.

    Thank you very much for letting us know of your concern.  We appreciate comments that can help us maintain the quality of our tests.


Nontas Konstantakis

Should I bother to respond?  Or maybe on the next physics test I should give full credit to the student that uses 78 grams for weight?!

Arlyn DeBruyckere
Hutchinson High School


The Irascible Professor thanks Arlyn for the permission to publish this interchange, and names him Honorary Irascible Professor of the Week.  In the IP's opinion, the response from the Educational Testing Service is arrogant in the extreme.  Instead of just admitting that they made a mistake and promising to correct the error on future tests, they persist in defending the indefensible.  The result is that those students who took the test and who know that a gram is a unit of mass not weight, but chose (b) because it was the answer that ETS was looking for will be a little more cynical about the testing process.  At the same time, those student who do not know that a gram is a unit of mass rather than weight, but who chose (b) because it was the "best" answer will have their ignorance reinforced thanks to the sloppiness of the ETS.


The Irascible Professor invites your comments.
©1999 Dr. Mark H. Shapiro - All rights reserved.