Air Resistance for Dummies

As we've pointed out many a time in these pages, perhaps the most powerful enemy of accuracy at the old eHow.com website was their minimum word requirement. Contributors, as they called themselves, faced with padding a simple answer out to at least 300 words often found themselves floundering in unfamiliar terminology and concepts. For an example of the results, today we'll take a look at a post titled "What Happens to Air Resistance as Objects Move Faster?" The post was written for eHow.com by Cindi Pearce and later moved to Sciencing.com by Leaf Group.

Pearce, already a three-time winner (on two websites), managed to get the basic answer more or less correct:

"As an object begins to move faster, air resistance... increases."

Not that someone with a science background would say, "...begins to move faster," since that suggests acceleration rather than different speeds. But what the heck, it's close enough for a journalism degree like Cindi's. Sadly, there's lots in the other 381 words Pearce barfed up that isn't close enough. We're talking semi-scientific twaddle like,

• "Drag occurs when air pulls on moving objects..." – She said "pulls"? Really? We guess that's her synonym for "opposes"...
• "When the air is denser, this slows down the movement of objects because the object has to shove aside heavier molecules." – Cute sentence, but here's a hint: denser air does not mean it's composed of "heavier molecules."
• "The force of gravity is referred to as the weight of the object." – Words will not suffice.
• "How much air resistance [a falling] object encounters depends on the speed the object is traveling and the cross sectional area of the object." – It also depends on the air density, a factor Pearce already mentioned!
• "Fluid friction is air resistance." – That's backward, Cindi: air resistance is a class of fluid friction.

Perhaps the statement that most reveals Pearce's scientific illiteracy is this:

"...gravity has more of an impact on the object then does air resistance. If air resistance were the larger of the two forces, falling objects would float and never fall to the ground."

We aren't certain, but we think that's Cindi's attempt to explain the concept of terminal velocity. Those of us who've passed a high-school physics course know the sentence is a sophomoric description of buoyancy, rather than air resistance. Yeah, confusing buoyancy with drag: that's about what we expected out of a journalism major assigned to pound out 300 words on a physics question and fact-checked by another journalism major. That's why eHow types like Pearce so often end up receiving the Dumbass of the Day award.

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