Posts Tagged ‘weight’


Dumbing Down the News

January 6, 2009

So I see this article today, and I get to the third paragraph…


Huh?  What??  Mass is “like weight”???  A 5th grader could probably tell you mass is not “like weight.”  A two second Google search for the definition of mass reveals that mass “the property of a body that causes it to have weight in a gravitational field.”  Mass is the amount of matter that a body contains.  Apply that matter to gravity, and you have weight, which varies by the strength of the gravitational field.  In other words, you might weigh 100 pounds on Earth, but you’d only weight 38 pounds on Mars, with has 38% the gravity of Earth.   But your mass wouldn’t change.  Mass is a description of the object.  Weight is a description of the force of gravity on the object.

Wikipedia says regarding mass that “the distinction between mass and weight becomes important for measurements with a precision better than a few percent (due to slight differences in the strength of the Earth’s gravitational field at different places), and for places far from the surface of the Earth, such as in space or on other planets. (emphasis added).  Too funny, given the article above.

Are we too stupid in this country to know the difference?  Do we really have to have it explained to us as “like weight?”  Let’s look at it another way.  Newton’s Second Law, dealing with inertial mass, states in equation form that  F = ma (force equals mass times acceleration).  So if a pro baseball player threw a baseball at you, the force of it hitting you is equal to the mass of the ball times the acceleration of it coming at you.  Quite different than if I lobbed one at you.  I bet if the author was hit by the lobbed ball, and then by the 100 mile per hour fastball, he wouldn’t think that they were like each other at all, even though the mass of the ball is the same.  Hmm…. let’s try it and find out!

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