One of my favorite MYTHBUSTERS quotes is “Jamie wants a boom.” In Saturday night’s new episode of MYTHBUSTERS, Jamie got plenty of boom and so did MYTHBUSTERS fans. In fact, throughout the show Adam Savage and Jamie Hyneman recounted many of the hundreds of explosions in a fascinating montage of pops, fizzles, and booms over fourteen flashy seasons. All told, they had used 18 tons using more than eight types of explosives, the most famous being 850 pounds of ANFO and the biggest using 5,000 pounds.
To officially begin this final season, MYTHBUSTERS started off with an “Explosions Special.” It’s hard to imagine topping anything they’ve done in the past. But try they did. Their myths to bust included testing passing through a mine field with a hovercraft and a clip from a MACGUYVER TV episode involving blunting the effects of an explosion by smothering it in wet cement.
Smothering an Explosion with Cement
In the original MACGUYER clip, Angus MacGuyver discovers a ticking time bomb in a mail delivery truck. He talks a cement truck driver into filling the delivery truck with wet cement, covering the bomb so when it goes off you see a flash but it smothers the explosion. No harm, no foul.
Adam and Jamie set up an empty mail delivery truck as a control sample, surrounded by plywood “shrapnel capture” models (stand-up figures), and pressure sensors at 20, 30, 40, and 250 foot distances. They wanted to test how dangerous the blast would be to bystanders and they wanted to test for a blast wave. Using 84 pounds of dynamite as they saw in the clip, they detonated the explosion and were totally surprised by the results. Not only did the blast destroy the truck, it blew away all the stand-up figures and took out all the pressure sensors, meaning they had no control data.
Then they tried the as-seen-on-TV version. To keep the explosives from floating to the top in the wet cement, Jamie bolted a table to the floor of the truck and put the explosives under it. But pouring the cement in they found that the explosives still floated out. After re-securing the explosives under the table, they finished filling the truck with cement – 16 tons of it, which had the truck nearly bursting at the seams. When Adam triggered the explosion, it appeared that the cement had smothered the explosion. But looking inside, they discovered two bags of unexploded dynamite that must have floated loose. Unaccounted were two stick of dynamite, which was apparently all they had exploded.
So Adam and Jamie made a third attempt. In this version, they put the explosives in an enclosed box and secured it to the floor of the truck. Then they filled the truck with wet cement and detonated the 84 pounds of dynamite. This time all the dynamite exploded, blowing the truck to smithereens. Unlike the control version, there was no pressure wave. The cement altered the direction of the blast, sending it upward and downward, creating a crater where the truck had been. It did, however send out a rain of shrapnel, filling the stand-up shrapnel capture models with holes.
Did it alter the blast? “Indeed,” said Jamie. Did it protect people in the vicinity? “Not at all,” answered Jamie. Did it match what they saw in the TV clip? Adam and Jamie agreed it didn’t.
- Conclusion: Busted!
Driving a Hovercraft Through a Minefield
The one kind of explosive that MYTHBUSTERS has never attempted has been a minefield. So Adam and Jamie set out to test the limits of one using pressure transducers as sensors and powered mortars to replace C4 to replicate the most common type of mine. Between Adam and Jamie, they created twenty fake mines and spaced them every three feet across a straw covered dirt field.
First they set the pressure at 30 pounds and Adam walked blindfolded across the field, easily setting off “mines” and allowing himself to be harmlessly pelted by dirt and stones. Then they reset the pressure at 300 pounds and drove Adam’s 3,000 pound Jeep across the field in an S pattern, again easily setting off the mines. The final trial was using a hovercraft.
Their thinking was that a hovercraft distributes its 630 pounds equally over its under-surface, whereas a human and the Jeep make point of contact, the human with its foot and the jeep with each tire. A hovercraft should pass over a minefield with no problem.
Adam and Jamie drove the hovercraft in the same S patter with the mines set at 300 pounds of pressure and didn’t set off a single mine. Then they reduced the pressure to 30 pounds. Again, they didn’t set off a single mine. Finally, they set the pressure at 5 pounds, a setting so light even a rabbit could set it off. But even at that light a setting the hovercraft didn’t set it off. Jamie figured out that with the hovercraft distributing its weight equally, it was only exerting 0.0063 pounds per square inch of pressure, not enough to budge the sensors.
“This is about as easy a myth to call as we’ve ever called,” said Adam.
- Conclusion: Confirmed.
This episode looked at the faint attempts to blow things up at the beginning of the series all the way through the big blow ups through this episode. I’m sure there are more to come through the eleven or so more episodes to come. As the two walked away into the sunset, Jamie shrugged, “At this point we’ve probably blown up more weird crap than anyone alive.” Amen!
In case you missed this MYTHBUSTERS episode, it repeats Wednesday at 9:00 p.m. ET/6:00 p.m. PT and midnight ET/9:00 p.m. PT on the Science Channel.