## Mini Myth Medley

That’s statistically better than guessing by a little bit.

This was Adam’s observation regarding people’s ability to identify the palms of their hands.  In their experiment, 7 out of 12 people correctly identified their palm.  I can only guess that Adam’s was implying that 6/12 would have been the result of “guessing”, but of course, since they had to pick their palm out of 10 palms, you’d expect the guessing rate to be 1/10 (or 1.2/12), so 7/12 is significantly better than guessing.  People were truly able to identify their own palms to an extent.

As for identifying the backs of hands, the experiments were kind of problematic.  To the best of my viewing ability, all of the “control” participants took the picture with the peg in between the index and middle finger.  I did not see one exception to the rule; it looks like Adam was rigorous in producing consistent pictures. However, most, if not all of the 12 volunteers they brought in to identify the backs of their hands placed the peg between their ring and middle fingers. I really can’t fathom how

1. they let this happen
2. they didn’t notice that there was a problem

Now, that doesn’t mean that people are not better able to identify the backs of their hands, but I think it’s dangerous to conclude that after such a flawed experiment.  Furthermore, after 10/12 people were able to identify their own teeth, I think out of such a small sample, that’s essentially the same rate of recognition as the (flawed) back of the hand tests, where 11/12 people identified the back of their hands.  Maybe this is something they’ll tackle in an episode where they revisit old experiments…?  On the other hand, this isn’t the sexiest of tests (there are no explosions or fires), so it might not merit a revisit.

Finally, let’s look at the glass-breaking needle.  I don’t know who  is in charge of calculating kinetic energy at Mythbusters, but they need to fire them.  It seems to be the number they most consistently misrepresent.  In this case, we are informed of the Mythbusters’ respective throwing abilities:

• Kari: 28 mph
• Grant: 38 mph
• Tori: 47 mph

As Tori is about to try his hand at breaking the glass, the narrator tells us that his needle has 40% more kinetic energy.  Based on the context, I assume he means 40% more than Grant, but I wouldn’t swear it.  Anyway, if you take a ratio of two values, and the numerator is 40% greater than the denominator, the ratio will be 1.4.  Let’s see here:

$\frac{KE_{Tori}}{KE_{Grant}}=\frac{0.5m_{needle}V_{Tori}^2}{0.5m_{needle}V_{Grant}^2}=\frac{(47\;mph)^2}{(38\;mph)^2}=1.53$

This of course corresponds to a 53% increase in kinetic energy.  So once again, I have no idea how/why they’re calculating kinetic energy…