Mythbusters 8/30

[nataylor]

That's more like it! Testing out a cool device and explosions. What's not to love?

It would have been great if they could have built a bigger linear actuator. It's amazing what just 6 pounds did. Also, I wonder if the motor had true sinusoidal movement, which is what you would have needed to maximize the vibration.

I'd love to see them test out some of Tesla's other stuff.

The Big Bertha lava lamp exploding was awesome. I just wish they had used a slightly higher frame rate on their high speed camera. Looks like they were doing 500fps. 1000fps would have been super cool.

[Church AV Guy]

In one of the slow motion shot, it was obvious that the glass envelope of the lava lamp didn't break into large pieces, but into a large series of thin strips (shards) that, as they said on the show, could be very damaging, if not outright lethal.

A structure the size of a bridge is likely too heavily damped to be shaken apart by such a device. The tests they were running on the steel beams would likely have been better if they had suspended them by thin wires or cable, reducing the dampening.

A much simpler device, though not Tesla's design is a motor with a large flywheel attached. The flywheel has a slot, and the slot has a bolt and a weight which can be slid toward the center, or the edge of the wheel, making the center of gravity of the whole thing off center. When you turn on the motor, it moves back and forth in a sinusoidal motion which can be easily varied in amplitude and frequency by adjusting the motor speed and the off-balance weight position.

Hmmm The contents of a lava lamp are highly flammable. That sounds like a bad idea to me. Maybe someone should come up with different contents.

[DancnDude]

The giant can of beans exploding was awesome!

[sschwart]

The giant can of beans exploding was awesome!
Gross is the word I would have chosen.

The lava lamp myth was far cooler to me than the tesla "earthquake machine". But a neat episode.

[Idearat]

I wonder why they didn't just bolt the actuator to a structural upright in their shop? That seems like it would have been similar to the Tesla story.

They could have used that actuator to build their jumbo subwoofer a couple weeks ago, it would have been more effective than the goofy driveshaft thing they did.

[DancnDude]

This (http://www.youtube.com/watch?v=9lQaIdDI5OE) is what I was thinking of when they were doing the resonance myth. Although this was caused by wind.

[Michelle5150]

Interesting to me was the lava lamp guy referenced in the myth lived in the town next to ours. There's alot of stupid people and stupid stories like that that come from the south end around here. The lava lamp guy is hardly the worst of them either.

Watching the big lava lamp explode in slo-mo was pretty cool though. :D

Anyway, i'm just waiting for them to test wether or not an elephant can jump though Kari's earrings. I'm betting on yes.

[nataylor]

Anyway, i'm just waiting for them to test wether or not an elephant can jump though Kari's earrings. I'm betting on yes.And I thought I was being nit-picky noticing her constantly changing hair color through the course of the myth. ;)

[vman41]

When they discussed the Tesla device and kept mentioning feedback, I got the impression the device should automatically find the resonant frequency of whatever it was attached to. Their gadgets still had to be manually tuned.

I wonder if the Lava Lamp guy started to see the lamp overheat so tried to cool it by dowsing it with water.

[lordargent]

This (http://www.youtube.com/watch?v=9lQaIdDI5OE) is what I was thinking of when they were doing the resonance myth. Although this was caused by wind.

Tacoma narrows. I don't even have to click the link to know that.

Anyway, it was a badly designed bridge. If they could find an old bridge that hadn't been retrofitted they might have had a greater effect.

[modnar]

Didn't they mention the Tacoma Narrows bridge when they did the "Break Step Bridge" myth some time ago?

[Church AV Guy]

Tacoma narrows. I don't even have to click the link to know that.

Anyway, it was a badly designed bridge. If they could find an old bridge that hadn't been retrofitted they might have had a greater effect.
Yes it was, but in the defense of the designers, no one had even seen vortex shedding do that to a bridge before. After that incident, many bridges were reinforced to resist the effects. It wasn't the designers fault, per se, it was just that they had the bad luck to have designed the bridge with just the right span, and one day to have the wind just at the right velocity to destroy the bridge. When I was in engineering school, we showed that dozens of bridges that were around at that time would have had the same fate if the wind had been just right. It just shows you that there is always some mechanism that no one thought of still lurking out there.

And speaking of things I didn't know about, I didn't know that lava lamps were still available, much less in different sizes, and that you could get just the filled glass part without the rest of the lamp. I thought it was one of those things that were gone, except for memories. What a surprise that you could just go to a lamp store and buy a bunch of them.

[bluenoise]

I have a lava lamp on my desk, but the bulb is burned out and I keep forgetting to get a new one.

The bridge they played with on this episode is gone, now. It was removed a couple of months ago, so it was cool to see them use it for their experiment. I would've liked to see them try the actuator mounted along different axes, not just side-to-side.

Was anyone else bothered by the announcer pronouncing "patent" as "PAY-tent?" I've never heard it pronouced that way.

[modnar]

Was anyone else bothered by the announcer pronouncing "patent" as "PAY-tent?" I've never heard it pronouced that way.
I noticed that, too. There was something else the announcer said in a recent episode that I didn't think was usually pronounced the way he pronounced it, but I can't remember what it was right now.

[SteveInNC]

The people that produce the show are the same ones that do Beyond Tomorrow, formerly Beyond 2000, based out of Australia. The narrator is also out of Australia.

[bluenoise]

The people that produce the show are the same ones that do Beyond Tomorrow, formerly Beyond 2000, based out of Australia. The narrator is also out of Australia.

Yes, but his lack of an accent makes that pronunciation seem out of place.

[JediCowboyD]

And I thought I was being nit-picky noticing her constantly changing hair color through the course of the myth. ;)
You noticed her hair?

[ClutchBrake]

I noticed that, too. There was something else the announcer said in a recent episode that I didn't think was usually pronounced the way he pronounced it, but I can't remember what it was right now.

The way he pronounced lava was annoying me as well.

[ikobi]

I have a lava lamp on my desk, but the bulb is burned out and I keep forgetting to get a new one.

The bridge they played with on this episode is gone, now. It was removed a couple of months ago, so it was cool to see them use it for their experiment. I would've liked to see them try the actuator mounted along different axes, not just side-to-side.

Was anyone else bothered by the announcer pronouncing "patent" as "PAY-tent?" I've never heard it pronouced that way.

CaNAYdian.

[pmyers]

Honestly, I thought this entire episode was pretty boring....the lava lamps were only mildly interesting.

[wmcbrine]

I was kinda surprised they called it "busted" after they achieved such impressive results. I'm sure they'll get a lot of feedback from the Tesla nuts.

[byte_me123]

Tacoma narrows. I don't even have to click the link to know that.

Anyway, it was a badly designed bridge. If they could find an old bridge that hadn't been retrofitted they might have had a greater effect.

Some thing I was thinking. In the test rigs they used at M-5, they were using new late 20th early 21 century steel. Back it the early days, steel was known to have impurities in it. As an example the steel used on the Titanic was found, on pieces they brought up, was less pure then todays. And therefore more prone to breaking.

[byte_me123]

Yes it was, but in the defense of the designers, no one had even seen vortex shedding do that to a bridge before. After that incident, many bridges were reinforced to resist the effects. It wasn't the designers fault, per se, it was just that they had the bad luck to have designed the bridge with just the right span, and one day to have the wind just at the right velocity to destroy the bridge. When I was in engineering school, we showed that dozens of bridges that were around at that time would have had the same fate if the wind had been just right. It just shows you that there is always some mechanism that no one thought of still lurking out there.

And speaking of things I didn't know about, I didn't know that lava lamps were still available, much less in different sizes, and that you could get just the filled glass part without the rest of the lamp. I thought it was one of those things that were gone, except for memories. What a surprise that you could just go to a lamp store and buy a bunch of them.

Oh they are still being sold, some under different Co. names.
I've seen one Lava lamp in Wal-Mart a few months ago that stood four feet high.
As to the ballistics jell rib cage dummy they made, the human chest is not one sold mass. The lungs, that takes up the most room, for example does have air in them moving in and out. so I’m not sure if it was a ‘real’ test of the effect of glass entering the chest cavity.

[JMikeD]

Was anyone else bothered by the announcer pronouncing "patent" as "PAY-tent?" I've never heard it pronouced that way.

If he was referring to "patent" as "easily recognizable," as in "patently obvious" then that's the preferred pronunciation.

It's a soft "a" when you're talking about an exclusive right granted by the government.

[stark]

He was talking about Tesla's patents, so it should have been the soft "a".

[Jeeters]

And speaking of things I didn't know about, I didn't know that lava lamps were still available, much less in different sizes, and that you could get just the filled glass part without the rest of the lamp. I thought it was one of those things that were gone, except for memories. What a surprise that you could just go to a lamp store and buy a bunch of them.They started making a bit of a comeback about 5 years ago. I remember Walmart had quite a selection of them back then. I think both Walmart and Target still stock up on them at the beginning of every school year (they're popular in dorms).

[sushikitten]

I know they said the lava lamp myth wasn't busted, but did the heart/balloon actually bust? No, otherwise they would have said so. Also, I know that that one large shard of glass was impaled, but it didn't seem to be in that far (but then again, I am going by my eyes) - they really needed to pull it out and measure the depth. They kept saying fatal, but I just can't believe it was really FATAL. Bad burns? Surely. Deep gashes? Bingo. But fatal?