Episode 128: Greased Lightning

Air Date: October 28, 2009

If a person tries to put out a stovetop grease fire by pouring a small amount of water on it, a fireball exceeding 30 feet (9.1m) in diameter will result.


Adam and Jamie started stove fires with three different cooking materials: canola oil, peanut oil, and lard. The ratio of oil to water was 8 to 1 in each case, with 64 US fluid ounces (1,900 mL) of oil and 8 US fluid ounces (240 mL) of water. In each case, a large fireball formed when the water was poured in, due to the sudden formation of steam which propelled the burning oil upward. No fireball reached higher than 25 feet (7.6 m). To investigate further, Adam and Jamie did some smaller-scale tests, varying the oil/water ratio and the shape of the cooking pot. The latter had no apparent effect on the fireball height, but they decided to use a 2:1 ratio (2 US qt/1,900 mL of oil, 1 US qt/950 mL of water) for further full-scale work in a mockup kitchen set. Under these conditions, they were able to get a 30-foot (9.1 m) fireball; however, they declared the myth busted because the original 8:1 ratio did not generate the stated result. In a further test, they set up a shelf to drop an unopened can of soup into the oil, reasoning that having all the water-based material at the bottom of the pot would more effectively launch the oil when it vaporized and exploded. The result was a fireball with an estimated height of 100 feet (30 m).

It is possible to extinguish a grease fire with enough water.


Adam called in a firefighting helicopter, which dropped 500 US gallons (1,900 L) of water on the grease fire and successfully extinguished it.

A person can detonate a block of C-4 (and escape) by placing it in a microwave oven and heating it for one minute.


The Build Team set up three microwave ovens, each of which contained a different C-4 device: one unaltered block, one with wiring similar to that used in the film, and one with both wiring and a blasting cap. Using a remote-controlled bomb disposal robot, the team set each oven to run for 60 seconds at full power. The unaltered block did not heat up appreciably, while the one with only the wiring caught fire but did not detonate (though the door of that oven did burst open). The wiring/cap device exploded violently after only a few seconds of heating, due to sparks arcing across the metal wires and touching off the blasting cap. Since a person placing this bomb in a microwave would be unable to get to safety before it exploded, the team declared the myth busted.

(This myth is based on a scene from the film Grosse Pointe Blank.)

A block of cheese can be fired from a cannon with enough force to shred a ship’s sail.


The Build Team evaluated three different cheeses for hardness, stiffness, and elasticity: Edam, smoked Gouda, and Garrotxa. They set up a canvas sail made with period-accurate materials and methods, and fired one sample of each cheese at it. Edam, the softest of the three, bounced off the sail without damaging it; Gouda, the hardest, was too brittle and broke up into fragments as soon as it left the barrel; but the Garrotxa, having the right mix of hardness and elasticity, remained intact and punched a hole in the canvas. Even though the exact type of cheese did not match the accounts, the team declared the myth confirmed.

(This myth is based on accounts of a 19th-century South American naval battle in which a Uruguayan commander was forced to use slabs of Dutch Edam instead of cannonballs when the ammunition ran out.)


  1. don says:

    i’m positive that anyone who knows the original myth (enough to burn the facial hair off your face will result) was satisfied with the experiment, but not with the conclusion.

  2. H says:

    So the exact type of cheese not matching is acceptable, but a large fireball not being precisely 30 feet is unacceptable?

  3. robert svorec says:

    this is not a true test, you did not allow for the wind , the fireball was blown sideways wich would impede its upward travel,, if it was done in a windlass situation it would make it to the 30 foot mark…….

    • Jennifer says:

      This was a factor at first but then they redid the experiment in a fireproof room where no wind could come in and it still didn’t reach 30 ft

    • Bob says:

      They measured it on the high-speed camera. Rulers and the Pythagorean theorem work on windy days, too.

  4. mike says:

    I agree with Robert. I was looking for a place to post the same response. It clearly shows how the wind is a factor.

  5. Stuart says:

    Yes, the wind inhibited the rise of the fireball in the air…looking at the footage and estimating for the wind you had two of the three (lard excluded) that WOULD have made 30ft.

  6. Tony54 says:

    As far as lighting C4 in microwave that should be CONFIRMED. They didn’t know how to use a microwave. Set the first stage to 0 power (how many minutes before explosion) the second stage full power. Every microwave that has a electronic timer can do this.
    If you want to verify this type
    Time 10 power 0 then Time 30 Start
    It will give you 10 seconds of 0 power then 30 seconds of Full power to set off the C4.
    In the real word you would set it for 5 – 10 minutes for 0 power to get away not 10 seconds.

  7. Kiming says:

    On Oil fires Disaster . I think use different temperatures of water. Example:100℃ water ,16℃-20℃ water and ice

  8. Geoff says:

    The fireball reaching exactly 30 feet is very much beside the point. How many kitchens have 30 foot ceilings on them?

    • Jogi says:

      Lucis is a little biudde of mine from the golf course I know his mother and father and grandparents he is a great little child and his pictures are just wonderful. They are very very good, You did a wonderful job. fish

  9. Mark says:

    I still think that a 30 ft fire ball is still plausible. They used peanut oil which has a flash point of about 450°F, But what about Almond Oil which has a flash point of about 495°F or Avocado oil with a flash point of 520°F? Even Extra Light Olive oils can have a slightly higher flash point than Peanut oil and it is commonly used in cooking.

  10. frederick says:

    If you all think you can do better why don’t you try and then film the results and post them on youtube? What is the saying “either put up or shut up”?

    • Josh says:

      Because, simply put at the beginning, middle, and end of every episode, “DON’T TRY THIS AT HOME” is probably impeding these loyal fans from doing there own experiments…

  11. Lyss says:

    This is the first time I’ve commented on one of the myths. The wind clearly moved the fireball away from the 30 feet mark. They really screwed up on this one!

  12. Alexis says:

    I have to chime in as well regarding this myth. The experiment was clearly done on a windy day, and as a result the fireballs were blown sideways. If you measure the height of the fireballs along the diagonal, you will get 30 ft (or very close) for the first two tests.

  13. MarkA says:

    Re C4 in microwave (Grosse Point Blank), to me it does appear that the C4 is NOT set off by the microwave itself but is set off by the microwave stopping.
    My rationale is that there is a glass bulb containing mercury attached to the C4, the centrifugal force of the rotating plate keeps the mercury away from the wires, (clearly visible when Martin Blank looks into the microwave during the gun battle) when the microwave stops rotating the dish the mercury moves towards the centre, touching the wires therefore completing the circuit and BOOOOOOM!

    • Jeff says:

      I know! It kills me that they didn’t put this together since it’s actually a clever trick. Instead they busted it!

  14. Eric says:

    This episode really cheesed me (pun may be intended). They were close to 30 feet and I am sure this “myth” was more of a ballpark height. A couple feet short is still fine in my books. Grease fire + water = bad…always!

  15. Well Hello says:

    I just saw this episode here in finland. I saw how windy day it was from one camera mans shirt or something… it would be that 9 meters if you would have done the test inside…! Nobody uses stoves outside!!

  16. Mandy says:

    I request a re-do!!!! You must block the wind! My husband and I have worked in kitchens for to long to see the 30 ft. myth busted. Re-do

    • Jennifer says:

      Everyone is saying the wind moved the fireball to a side but the results were still reliable because wind is everywhere. If that were to happen in real life to a house there would also be wind so that’s not a great huge factor. The measurements were just not right. So stop complaining how the wind was a huge factor that screwed everything up.

  17. nick says:

    What is lard anyway?

  18. ac220 says:

    @nick: Basically it’s pig fat, heated to melting then cooled.

    @ everyone complaining about wind… You’re kidding, right? It’s the same thing as with dropped vs fired bullets, – exotic aerodynamics and equipment inaccuracies aside, pushing something sideways does not affect it’s vertical movement.

    • cnuffs says:

      U can’t be serious?? It’s obvious they had the wind blocked the first 10ft or so and as soon as it went past that the wind impeded the height for a sec. It’s just like when u light a candle n blow on it, the flame goes sideways. Wind did mess with the height. They were too lazy to do a real test over with real results. Should’ve took the elements out of the equation.

  19. Logak says:

    I do think being rigid about the 30 feet is a little unnecessary. My thoughts: when people see a massive fireball shooting out of their pan, they aren’t exactly trying to measure the height of the thing – on the contrary, they’re probably tearing the heck out of there. So someone could estimate 30 feet, but maybe it’s not quite that high.

    Then again, the myths are generally about the claims as made. So they were testing the claim itself – not whether it got close. I would conclude that the plume from water on a grease fire of the right type of grease would get high enough that people would THINK it was 30 feet, but not high enough that it actually is.

    On a side note, the “can cheese be shot out of a cannon” myth was the first one that make me laugh out loud just from being mentioned in the intro. Still one of my favorite myths due to sheer absurdity.

  20. theothalopathis says:

    Did you like shoting the Cheese in the Cheese Canon.
    we are from iraq and this is the first time we have seen tv.

  21. Angel says:

    does anyone still use lard any more?

  22. gillotte says:

    @ac220 youre wrong on that. obviously wind pushing fire sideways will lower the total height it will reach. to go straight up to 30 feet all you need is to reach 30 feet. how much more do you need to go up if youre blown sideways? 30 feet is only 30 feet in a straight continuous line. example. you have to string thread from 1 spot to another spot 30 feet away but its not a straight shot across. about halfway across you have to make a 30 degree angle turn for 5 feet then again back to a straight line. do you honestly think youll only need 30 feet of string to make it across?

  23. michael says:

    I think you are wrong
    if I drop a 30ft rope in carm day it drops 30ft it I do it when it is blowing a gale it dose not reach 30ft

    we could argue this a lot but I think it would be better and more fun if they retested it

  24. nick says:

    I agree with michael and gillotte going sideways would lower the total height

  25. Richard says:

    Notice how the fireball drifted to the right as soon as it rose above the 8′ high windblock on the left? I’m sure that had they done it on a calm day, it would definately blown past the 30′ mark.

  26. Andrej says:

    The Part with the grease fire

    they should retest this… i think it is possible to get a 30 feet high fireball with peanut oil and 8 US fluid ounces of water, if there is no wind…

    you can see, that the wind influenced the fireball

  27. Markno Hawking says:

    I have a an issue with the grease fire and a couple of observations.

    First the complaint; how in the world can you expect to accurately measure a vertical rise of exploding gasses with a cross wind? Come on Adam, I have come to expect so much more from you. Gee Jamie, you usually catch Adam when he does these things.

    Trying various oils looks like molecular cohesion was a contributing factor. The thicker the oil source the lower the fireball seemed. But that could have been tainted by the a fore mentioned crosswind.

    The fireball is created when burning oil is expanded by the water turning to steam at a very rapid rate thus introducing a greater supply of oxygen as well as a “path of least resistance” in a vertical orientation and carried up by the intense heat rising. As all pure water changes to steam at 100*C (*=degrees on my keyboard) and you have no pressure vessel to increase the temp. of steam, changing the temp. of the oil or the water would seemingly have very little effect. What would do the best would be to have an oil that has a lower burn rate but a very low viscosity and weight. Thus going higher and burning long enough to make it to 30 feet.

    But then again, I am no scientist.

    • Remus says:

      Good point with the wind! I also wonder, whether the ignition temp. is the final possible temp. achievable. I’m convinced that if they waited a bit the fiery column could be higher.

  28. Markno Hawking says:

    So, like my teachers used to say, “Do it over and do it right this time.”

  29. Geoff says:

    Hmm, just had a look at the cheese cannon on youtube… Somehow I don’t think they would have taken the time to cut it down and remove the wax before firing it… I think the paraffin wax would have made a huge difference

  30. Geoffrey says:

    My house almost just burned down because of a small household fryer fire, mom’s bf threw water on it which made the flames jump to the ceiling, then grabbed the mop i had soaking in bleach water which almost completely engulfed the whole kitchen. I was there almost immediately with flour and succeeded in extinguishing the fire but not before minor damage occurred in the kitchen

  31. Giftish says:

    So, no one noticed how windy it was when this myth was done? This I a myth burning down a house, no wind what so ever. Do this myth inside.

  32. jon says:

    was ice cold water used

  33. Tom says:

    although the C4 did not explode with the battery, if an older zinc/cloride heavy duty wet battery was used the heat may have been enough to cause the battery to explode and provide the force for C4 explosion

  34. Emily says:

    To Geoffrey,
    Please do not use flour again–it is a fuel. Grain elevators explode after catching fire because of all the grain/flour dust in the air.

    Baking soda puts grease fires out safely if you do not have a fire extinguisher.

    Concerned for your safety,

  35. Alastair says:

    Pouring oil into a burning pan of oil. If you had used a chip pot ( say 9 inches high sides) rather than a flat skillet I’m sure the flame would have gone 30ft. The higher side would direct most of the blast upwards

  36. cnuffs says:

    Retest the grease fire. It’s obvious as soon as the fire ball went over the wall the wind impeded it’s height. It’s just like blowing on a lit candle it shortens the flame because it’s pushed sideways. Please retest this in a place with no wind instead of using outdoors and 30mph wind.

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