Mythbusters myth gone wrong

[APlotdevice]

The science is sketchy, at best. Like the episode where they test if a boat will split in half when hitting a stationary object... but they test it on land. Water has very different properties than air, so the whole test is completely meaningless... doesn't stop them declaring the myth "busted", though.

As they explained in a behind the scenes episode, that particular experiment was done on land for environmental reasons. However the only way I could see the choice fluids affecting the results is if they had tried to propel the boat to supersonic speeds. Otherwise air and water behave similar enough.

 

[Abyssgh0st]

Video.

Wow, that was worse than I thought. It flew through these people's house and flew over them while sleeping.

 

[snberk103]

Lets keep some perspective here. A suburb in the evening is 99.99% empty of humans. The probability of an object that size hitting a person are small. It would have been statistically unlikely that it would hit a person. So - really really happy no one was hurt, but not surprising.

That said.... I would not want to have cannon-balls fired anywhere near us! Yikes! There are the "stats", and then there is the gut-feeling that this was a really really bad experiment gone wrong!

 

[Abyssgh0st]

Lets keep some perspective here. A suburb in the evening is 99.99% empty of humans. The probability of an object that size hitting a person are small. It would have been statistically unlikely that it would hit a person. So - really really happy no one was hurt, but not surprising.

That said.... I would not want to have cannon-balls fired anywhere near us! Yikes! There are the "stats", and then there is the gut-feeling that this was a really really bad experiment gone wrong!

Except when the object flies through houses and cars that were just parked.

 

[interrobang]

How the hell does a cannonball go up stairs, smash through a wall, bounce off all sorts of other crap along the way, and still have enough velocity to fly over a 6 lane road? That's nuts.

Obviously, it's pretty dubious that something like this could happen. We need someone to test whether this is plausible or not.

 

[carlgo]

Makes it clear that facing cannons 200 years ago was not fun. They weren't those Hollywood gasoline puff explosions you see in movies, but powerful and very impactive.

 

[snberk103]

Except when the object flies through houses and cars that were just parked.

I can only make some basic assumptions about the house and people involved. I'm happy to be corrected on any math errors, of course.

If there were 4 people in that house, and the house was 2000 sq ft, (on two levels, ignoring the attic and basement) then they occupied 14 sq ft of volume, or just 0.07% (approximately) of the volume of the house.

If the cannon ball was 10 inches wide, and travelled 50 feet through the house, then it passed through just over 39 cubic feet of volume in the house, or just 0.195% of the space inside the house.

As you can see, there was lots of empty space still available in the house. And, consider that houses in the evening are likely the most densely populated areas in the suburbs. The only other densely populated area the cannon ball travelled over was the road. And that could have been much more densely populated, depending on the time of day.

Don't get me wrong... I'm not saying this is a "nothing" story! Just saying that it wasn't lucky that people didn't get hurt, it was statistics. It would have required bad luck for somebody to get hurt. Though, they probably would have been very badly hurt. Something that big and with that much energy is not going to deflect off somebody, it's going to go through them.

I'm assuming 3.5 cubic ft per person, a 2,000 sq ft house (1,000 per level), and that the house was 50 ft from front to back, and the cannon ball was 10 inches wide.

 

[NYR99]

My favorite show on TV. Glad no one got hurt.

 

[Rodimus Prime]

Lets keep some perspective here. A suburb in the evening is 99.99% empty of humans. The probability of an object that size hitting a person are small. It would have been statistically unlikely that it would hit a person. So - really really happy no one was hurt, but not surprising.

That said.... I would not want to have cannon-balls fired anywhere near us! Yikes! There are the "stats", and then there is the gut-feeling that this was a really really bad experiment gone wrong!

you got that backwards. During the evening the suburbs tend to be full mostly houses with people in it.
It is during the day when they tend to be empty.

 

[snberk103]

you got that backwards. During the evening the suburbs tend to be full mostly houses with people in it.
It is during the day when they tend to be empty.

A suburb may have the most people in it during the evening, but it is still mostly empty air. A 2000 sq ft house with 4 people in it is 99.93% empty (of people). This is not including the empty air over the rest of the lot, or the streets, sidewalks, and parks. And keep in mind that for every person that is on the streets, there will be one less person in a house (assuming that on average each house has an average of 2 adults, 2 kids. Even if you add a tradesperson/deliveryperson/etc at a rate of 1 for every single house - it doesn't change the fact that the errant cannonball was travelling through an area that was more than 99.9% empty air.

Still a serious problem, and not one I want to ever live through - because if someone had been unlucky, it likely would have been fatal. And if it was my neighbourhood, I'd have freaked a bit too! But I'd have been glad that no one was unlucky, not that we escaped by being lucky.

There is another bit of info I'm not seeing on this thread. That cannonball ended up 3/4 of kilometre away from the range, after bouncing off of a hill-side. They must have had quite the charge in the cannon to bounce it that far. Then imagine what it would have been like a couple of centuries ago when they were firing 40 lb balls of iron with enough force to send them several miles. Imagine sitting in a wooden ship that was less than a mile away from a battery of these big guns. Yikes!

Glad no one was hurt.

 

[Daffodil]

Definitely lucky no one got hurt!

According to Adam Savage's twitter feed, looks like they'll be leaving that part out of the episode. While I can understand that decision out of respect for the people involved, and to prevent more negative attention, it's sort of also the loss of a valuable teaching experience. Clearly there was some sort of miscalculation, or the "experts" involved weren't what they claimed to be. It also begs the question of why a residential area was built so close to a firing range, but I guess this sort of freak accident thankfully isn't too common...

 

[Demosthenes X]

in the boat test water or air really does not make much differences in the results of it since it is all about moment. Heck in water it would be harder to do not easier.
The only thing they might done wrong is the boat could of been turning witch would of provided that needed curve arch in the hit.

But your reasoning for calling it crap is not valid as water vs air would not of effected the result.

As they explained in a behind the scenes episode, that particular experiment was done on land for environmental reasons. However the only way I could see the choice fluids affecting the results is if they had tried to propel the boat to supersonic speeds. Otherwise air and water behave similar enough.

Have you ever actually driven a boat? Changing a boat's course in water takes a lot more effort than in just air. All of the water to the side of the boat needs to be displaced, and water weights significantly more than air. Simply put, the boat would not just ricochet off the side of the channel marker the way it did on land - the weight of the water would help keep it on course.

Just think about how long it takes to turn a boat on water than a car on pavement. You can't replicate the test on pavement and call it sound science. The water is a major factor that's taken out of consideration. If you search around you'll find lots of people saying the same thing - you can't do this test on land and call it conclusive.

 

[QuarterSwede]

Have you ever actually driven a boat? Changing a boat's course in water takes a lot more effort than in just air. All of the water to the side of the boat needs to be displaced, and water weights significantly more than air. Simply put, the boat would not just ricochet off the side of the channel marker the way it did on land - the weight of the water would help keep it on course.

Just think about how long it takes to turn a boat on water than a car on pavement. You can't replicate the test on pavement and call it sound science. The water is a major factor that's taken out of consideration. If you search around you'll find lots of people saying the same thing - you can't do this test on land and call it conclusive.

And if they ever can they'll revisit the myth as they've done plenty of times in the past when enough people complained.