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Episode 23: Exploding House, Needling in a Haystack, Talk to Plants

  • Blowing up a house with bug bombs: confirmed
  • National Treasure segment
  • Talking to plants affects their growth: plausible
  • Needle in a Haystack contest: Adam beat Jamie

Any MythBusters episode with an explosion is generally good, even if I was hoping for a slightly bigger one than delivered.

Bug Bomb

Adam and Jamie tested the myth of a house blowing up due to bug bombs. According to the myth, a family used 10-11 bug bombs in their 500 sq. ft. house to try and rid it of pests and ended up blowing it to pieces (one bug bomb would have been enough). Bug bombs contain a propane base in the aerosol that is plenty flammable.

They used four ignition sources to test the myth on a small scale plastic box with a single bug bomb. * Stove sparkers * Lighter to simulate pilot light * Wall plugin contraption with faulty wiring * Thermostat

After they figured out the shorts in Adam's wiring, they managed to blow up the container with the faulty wiring contraption. There was no explosion for the thermostat wiring, and they didn't show the others being tested.

For the full scale test they found a house due for demolition and loaded it up according to the myth. They only used the stove ignitor, which at first didn't work because Adam didn't have it the trigger plugged in. After plugging it in, they result was still the same -- the bug bombs and stove ignitor weren't enough to ignite the house.

They upped the number of bug bombs and used matches to increase the flame size. This time it worked -- they blew the sliding door off the house with a good flame blast.

This wasn't never really a myth as they showed footage of San Diego house that was bug bomb bombed and actually looked like it split apart. Bug bomb explosions occur at least once or twice a year in California.

Confirmed

National Treasure segment

Checked out the actual Declaration of Independence to see how well it is actually protected.

War of 1912 it was rolled in a linen sack and stored in a barn for safekeeping

Talking to plants

Build team testing how talking to plants (positive/negative) affects growth of plants. Also testing different types of music.

Seven greenhouses on Jamie's roof * silence * heavy metal * classical * 2 sweet talk * 2 abused

27 days: sweet-talking plants doing a bit better than the verbally abused plants.

2 months: all the plants are dying. Battery for timer feeding the water system died.

To recover the experiment, decided to wash plants and weigh plant mass.

Metal house the best performer by far, with classical in second. Talking nice/nasty made no difference. Kari's nice house did better, but Scottie's was the opposite. Silent house was the worst performer.

Plausible (not confirmed, given that the experiment wasn't really scientifically valid)

Needle in the Haystack

Not a myth, but an adage: Can you use modern technology to render the "needle in a haystack" adage meaningless?

For the experiment, it was a competition between Adam and Jamie to find their respective needles: one bone needle and three steel needles each.

Jamie's needle-seeking contraption: Long rotating tube with holes for needles to fall through, with magnet to catch magnetic needles. At the end of the tube, a burner to turn hay to ash and catch any needles that make it through.

Adam's needle locator: water tank, which would allow the hay to float through and the needles to fall. Three paddlewheel agitators to stir hay and move it out of the tank.

Jamie: "Adam's rig is actually fairly clever I think"

In the actual competition, Jamie took an early lead, finding the first steel needle after four hours. Adam's team made some modifications at Tory's advising, adding a strip of magnets where the hay was loaded into the machine. This allowed them to quickly find two steel needles and take the lead, and after six hours Adam's team had found the last metal needle. They had not yet found the bone needle, nor had Adam actually checked to see if bone needles floats. Jamie's team found second metal needle sitting on top of pile, but they could not catch up as Adam's team removed the agitators and located the bone needle at the bottom of the tank.

Jamie: "It's about time he beat me in one of these contests"

It was a weird competition, seeing as Jamie's machine never really worked as designed (no needle dropped through the slits), and three out of the four needle for Adam's machine were found by the addition of the mid-contest magnets.

Comments

The plant experiment was surprising to me, and I was disappointed they didn't get a little more curious about the huge difference between the greenhouses. They could have done better by replanting and moving each CD to a different greenhouse -- I suspect there is some environmental variable in there causing at least some of the variation.

The plant experiment was fairly bogus, as far I'm concerned. Entertaining, but bogus. With an indoor setup they would have gotten a little closer to controlling the variables, but my guess is that it wasn't worth their time to do a proper study.

Interesting experiment, and interesting store. I was curious what the name of the store was where the seeds were purchased. Thanks for any help.

the experiment was good, they tried all the variables, but they did not gave an appropiate reason/explanation to their current results, so i was dissapointed with these.

One possible reason for the plants that were spoken to growing better might be all the CO2 that was released from the people talking to the plants, then closing the greenhouse doors, thereby trapping the CO2 inside to some degree. Those that weren't spoken to probably would've shown decreased CO2 levels within each building. I demand a do-over.

To what peter said would be incorrect.
Plants strive off of CO2, in turn, give off oxygen.

But I do agree, they should re-evaluate. They probably would've if it weren't for the time it takes to do such a project, and the timing, they are required to get the episode finished.

I think they should use a backscatter x-ray to find the needles.