These viral video things are kind of boring. The subject matter isn't always very good.
Match heads: Yawn. What happens if you light a bunch of match heads at once? You get a bigger-than-usual flame. How is that unexpected?
Also, the parts about taking all day to cut off the match heads made me realize that Mythbusting must be a lot more tedious at times than they make it look with editing.
The cannon thing at the end was kind of interesting, though it had nothing to do with any myth.
And doesn't it sort of undermine the "Don't try this at home" warning when the whole reason this myth was being tested was because somebody tried it at home? Aren't they kind of endorsing and discouraging it at the same time?
Burning tire: I think that, looked at a certain way, they confirmed the myth. The question that was asked was, "Can you spin a tire so fast that it catches fire?" Well, the rubber of the tire did catch fire -- after smoldering for half an hour or so. So technically, the answer is yes. The Mythbusters were assuming the question meant "so that it catches fire while spinning?" But I don't remember that being specified.
However, they did conclusively bust the proverb "Where there's smoke, there's fire."
Lego ball: I figured the YouTube thing was faked. My guess was that they just carved the thing out of light wood or foam or something and just painted it to look like a Lego structure. It even looked like it might've been largely hollow.
I'm disappointed in the Mythbusters' technique. I mean, they needed to wait until they actually gathered the bricks to test whether the block could really have 5 million pieces? Hello? Ever heard of geometry? It's a complex shape, sure, but I'm sure someone with Grant's math skills could've estimated its volume, or they could've built a scale model, dumped it in water, and measured the displaced volume. Then just divide that by the volume of one brick and compute how many bricks it would take. Wouldn't that have saved them a lot of trouble, if they'd known at least roughly how many bricks they'd actually need instead of just going ahead without figuring that out first?
It's cool that they actually put a camera on the ball as it rolled. As for its disintegration, that's the sort of thing I didn't expect but that seemed inevitable once I thought about it. Given all the shifting stresses the ball was under, it shouldn't have been hard to figure out that the rather tenuous friction-based connections between bricks would be under strain throughout the structure. And as I recall from my days of playing with Legos, some bricks stick together more loosely than others.
I think they overlooked a way to test the last part of the myth, what would've happened if that mass of Legos had hit the car. Okay, they didn't have an intact ball, but they could've gathered them all up in a tarp or something and used some kind of construction equipment to lift it up and swing it against the car like a wrecking ball.
Come to think of it, if the ball had hit the car while still intact, it would surely have smashed apart, thereby absorbing a lot of the impact force, so the car might not have been that badly damaged by the weight. So having the bricks contained in a tarp, not free to separate, would not simulate that accurately. So maybe that wouldn't have worked. Although it would have tested the conditions depicted in the myth/video, namely what would happen if an intact mass of Legos that size were to hit a car.
General observation: Mythbusters has been on the air for six years now. That's six years each of experience for Adam and Jamie, adding up to twelve man-years of experience. So shouldn't they change the opening narration from "Between them, over thirty years of special-effects experience" to "over forty years"? True, over forty is technically still over thirty, but generally "over thirty" is meant to imply "under forty" (except when Isaac Asimov talked about his age). They've got over forty years of experience between them now, so they should boast about it!
