CSI experiment Question

In one of the older CSIs, Grisson uses a large trough, a fan, water pump, and model boat to find a real boat.

When I saw that episode, the experiment seemed so stupid that it couldn’t possibly work, but (here’s where the reverse logic comes in) the producers/writers wouldn’t put something so obviously false (unless it delt with computers) in the show, so the experiment must be a valid experiment (assuming that Grisson did many repititions).
So was my first instinct (ie the experiment was so ill devised that it couldn’t have worked) true, or was that experiment a valid experiment (ie someone could really have found a boat that way)?**

Well, there exist quite accurate models of major waterways (I saw a TV show about the San Francisco/Oakland Bay area that featured a warehouse-sized model that was kinda cool) but they’re built to precise specifications and not the kind of thing a CSI tech would whip up in an an afternoon.

In other words, the bullshit is strong with this one.

Sadly, the answer is that it’s a TV show and the producers will put in anything that makes for a cool script. There have been dozens of articles debunking the “science” on CSI.

And the more episodes they do, and the harder it becomes to use real forensics as a springboard for plots, the more cool-looking pseudoscience will be featured.

Still a great show, though.

So, you can accept that they’ll cheat with the Magic Unlimited Camera Zooms[sup]TM[/sup], but not that they’ll cheat with Absurdly Simple Models For Insanely Complex Phenomena[sup]TM[/sup]? :slight_smile:

Sure they would! (And did.)

CSI uses plenty of physically absurd scenarios. My favourite example is the episode where they filled a stab-wound with silicone, let it set, and then pulled out a perfect casting of a knife-blade, precise in every detail, which enabled them to identify the murder weapon by its uniquely chipped tip. Because the cavity that results from a deep, penetrating abdominal wound is perfect for that sort of thing, you know. :smiley:

It’s a great show, but the writers aren’t above inventing ridiculous or impossible solutions to further their stories. At all.

I think I remember that one, was that the one where the other set of CSIs took the tip to a knife maker, and he drew lines off the sides of the tip to make a sort of triangle, then grabbed a knife that didn’t match the sketch (it was skinnyer than the triangle the knifemaker drew) he made?

I quit watching CSI early on because of the ludicrous science. I mean, I’ll watch Monk, which is just as silly, but at least it doesn’t take itself seriously.

Even if the water trough were a perfect scale model of the real body of water, it still wouldn’t be a good simulation, because the water itself isn’t scaled down (nor can it be). Fluids are not, in general, self-similar at varying scales. The shapes of the waves, the drag forces, the turbulence, and a host of other effects wouldn’t all scale in the same way.

probably heading into GQ territory, but could you use a different liquid (with a higher or lower viscosity) to take into account the scaling effects?

The thing I like about CSI is not the science (which varys from pretty good to horrible), but the scientific process (for example, shooting at shirts at various distances and finding the one that matches the crime scene shitrt).

Also it shoukld be pointed out that even when there are real world doable tests done, they are time compressed (i.e. tests that take weeks if not months in the real world are done overnight) (at leats this my understanding)


Oh, look, it has a webpage. Surprise!

It was prominently featured in the “Escape From Alcatraz” Mythbusters experiment. Adam & Jamie managed to pull off the escape in reality, but as I recall, the model generally swept the model boat out to sea beyond the Golden Gate quite quickly.