Episode 88: Trail Blazers

Air Date: October 31, 2007

If the trail of gas from the leaking gas tank of a moving vehicle is lit, the fire can catch up to the tank and blow up the car.


Through small scale tests, the MythBusters discovered that gas burns at just over 3 miles per hour, which is as fast as a brisk walk. Next, they lit leaking gas trails from both a remote control car and a regular pickup, and the flame did not catch up to either. A car going at the low speed of 20 miles per hour could easily outrun the stream of fire. Finally, they let the gas catch up to the tank, and it did not explode. In order to create an explosion, the Mythbusters filled the tank with enough gasoline to get an ideal fuel/air mixture for combustion. Even so, they could not make the gas tank explode so this myth was completely busted.

One can outrun a trail of burning gunpowder and kick the trail out before the burning powder reaches its explosive destination.


In large scale testing, an even trail of gunpowder was laid out on a plywood floor. Adam outran the fire and kicked out the trail with plenty of time to spare. Jamie gave it a shot, but Adam hindered his attempt and the powder reached the end. The tests showed that the igniting gunpowder did not move very fast, with Adam showing that a brisk walk is enough to overtake the flame. The team finished by blowing up a keg of gunpowder. Adam called this explosion “the best we’ve ever done”.

A defibrillator can burn someone if the electricity arcs with an underwire bra.


Though the bra did cause a burn, it was only when the wire was exposed and the paddles were placed very close together and close to the exposed wire. This would not be likely in normal circumstances as the paddles would never be placed so closely together and medical staff are trained to remove possible obstructions before using a defibrillator.

A defibrillator can burn someone if the electricity arcs with a nipple piercing.


Though the nipple piercing did cause a severe burn, it was only when the paddles were placed very close together and close to the piercing. This would not be likely in normal circumstances as the paddles would never be placed so close together and medical staff are trained to remove possible obstructions before using a defibrillator.


  1. Zhoen says:

    So, why didn’t you just get your EMT pals to bring an AED, or other real defibrillator? A quibble.

    EMTs have trauma scissors to cut bras, and would. I would have to vote for Busted.

    I have heard of medical staff knocked off their feet when the defibrillator is activated, and they are still touching the patient after being ordered to “clear.”

    • Matt says:

      I was actually on a call for a patient in cardiac arrest who was found in his front yard on a summer morning. He had been mowing and suffered the fatal disrythmia. We performed CPR until the medic was ready to shock, and we all moved back when advised to “clear.” Well, the AED went off, and we all got zapped, because we were kneeling in the damp grass (dew) that the patient was lying on…

  2. eduardo gonzalez says:

    i not speak english but i very like this program but in discovery no have new episodes please new episodes in discovery

  3. Joshua Tisdale says:

    MARRY ME KARI!!!!!!!!!!!!!!!!!!!!!!

  4. Alexis Crosby says:


    Can you figure out the pattern and figure out the sentence????

  5. Paul Chwiecko says:

    Was the gunpowder modern smokeless nitro or was it black powder??

  6. fuzee says:

    hey kari just wanna say that i think ur really beutifull and i hav a big high school crush on u

  7. Danielle says:

    Hey Busters, my name is Danielle and i’m 13. I have an interesting myth I think would be intesting to prove or disprove. An Italian myth I found by trying to find a myth for my Destination Imagination team states that a long time ago a tarantulla spider would only bite a poor GIRL-tarantata-not sure if I spelled it right-(not of wealth or aristocratic upbringing) Sounds silly right? Well stay with me… the girl would go into a trance. To cure it, towns people would gather up with musical instruments and play different beats, each beat would cause her to go into different frenzied dances. If they found the right beat she would be cured, if not she was doomed. Ok ok I admit it’s crazy and it hasn’t been proved… but it hasn’t been busted! I know there are TONS of myths to bust but if you could find the time to prove it… I’d apreciate it! also I heard if you put salt on the tail of a bird it can’t fly. Try it, I’d like to know!
    I sorry it is a long comment but thank you for your time!

  8. William says:

    hy this is william can somone jump a fotbalfild?oh for the speeding car put all the things together.

  9. William says:

    skip the other one.what i ment was can you jump a footballfild on a motercycle? put all the ingredients for the speeding car on the license plate .

  10. Chris says:

    I believe Paul has a valid Point. Modern smokeless powder i significantly less reactive than original Black Powder. Having worked with the latter for several years, It might be prudent to test the difference at some point. As for the Defibrillator shock traveling through an underwire to shock someone, I know its rather possible. Usually this in combination with a wet person and one of the medical providers also being drenched. One of the EMT’s in one of my neighboring squads had this happen to him. No long term ill effects, just zapped a little from a hole in his shoe.

  11. gary says:

    i tried to make the perfict bullet by meshuring the wate of the brass slug and powder perfict it took me about an hour to make all most two eyedenicl bullets and it was kinda windy when i shot them at about one hundred and fifty yards and i was hoping thay wher going to be atleast a half inch off but it was a bout four inchis off and i know i shot almost in the same place it had to be the wind right but any was can you try to make the perfict bullet and see what hapens but i know for top acurasy make shur your gun and scope are clean and use somting like sand bags to rest your gun on.

  12. David says:

    Hi Danielle — You are probably thinking of an old Italian dance called the “tarantella”, which is in a fast 6-8 time. Apparently the folk people thought that this dance would cure the poisonous bite of a tarantula. Sorry, but it’s already busted. A tarantula isn’t even poisonous — It gives a nasty bite, but it’s not poisonous.

  13. Nick says:

    In the leaking gas tank experiment I think it was Jamie who said something interesting about jet fuel. Is there a place to find transcripts for this episode? I could not find it online. Thanks. Great show!

  14. Kevin says:

    Defibrillator myth – the experiment should have included a saline solution sprayed on the test body. If the person was sweating, the additional moisture would be conductive. Just a thought! Love the show – keep it up!!!

  15. stew says:

    I have a problem with the gun powder being kicked out. You showed that a trail of powder just poured ramdomly burnt fast and a constent trail burnt slower. How many cowboy’s would have taken the time to measure the trail. You should have tried it by pouring a trail from a bag and then trying to out run it. I don’t think you’ll make it. Myth busted.

  16. Nate says:

    The gun powder myth is incorrect. Try outrunning a line of FFF black powder which was used back in the day for muzzleloaders/muskets. Good luck.

  17. joe says:

    i like these guys. they just HAD to blow up something didnt they??

  18. Eero says:

    I think you should redo the burning gas trail myth under hot conditions. Evaporation will increase and the speed ought to do the same. Also it seems that fuel is mixed according to season, so you should use winter fuel for extra volatility.

  19. Caz says:

    I have a nipple piercing on the left side and the defibrillator myth has always kind of bugged me.. I always wondered about that.

    • Maddy says:

      Paramedics are trained to remove piercings first. I have 3 dermal anchors (permanent) in my chest. I’m screwed

      • Charlene says:

        American red Cross says:
        “■ Jewelry and body piercings: You do not need to remove jewelry and
        body piercings when using an AED. Leaving them on the victim does no
        harm. However, do not place the AED pads directly over metallic jewelry
        or body piercings. Adjust AED pad placement if necessary”
        Plus wouldnt you rather be alive with a mild burn then gone into cardiac arrest due to the delay in removing the jewelry.

  20. steve says:

    on the kick out the gunpowder trail myth

    Along with what’s already been mentioned would it not also been a different effect with dirt

  21. felixnoir says:

    In the days of sail, you had two types of fuses. Slow Match would burn at a metre a minute and Quick Match would burn at a metre a second. When setting a fuse, you would use say ten metres of Quick Match, with a bit of Slow Match at the end so you could get the hell out. The figures here may not be completely accurate: but the point I’m making is that gunpowder burns at different rates and people who were experts understood that very well.

  22. Melissa says:

    Can a car catch fire because of a gas leak??? Plz someone answer this for me because I am worried that my car will explode.

    • Guest says:

      Instead of asking someone to test this, wouldn’t it make more sense for you to go out and fix the leak?

Leave a Reply