Episode 116: Banana Slip/Double Dip

Air Date: April 22, 2009

A banana peel on the ground is guaranteed to cause the person who steps on it to slip and fall.


In their first test, a blindfolded Jamie (wearing body protection) stepped on a banana peel while walking, but did not slip. In the second test, multiple banana peels were laid down in Jamie’s path, but he did not slip. He then tried running through the banana peels but still failed to slip. They performed further tests by measuring a banana peel’s static friction and kinetic friction and comparing it to lubricant, with the lubricant having far less kinetic friction but the banana peel having somewhat less static friction. In their full scale test, the MythBusters built a race course that had the entire ground covered with banana peels, and later lubricant. They compared how quickly and easily they could negotiate the course with banana peels and the lubricant, doing comically poorly in both cases. In the end, the MythBusters decided that the myth was busted, but just barely: banana peels would not guarantee a fall but could still prove to be very slippery on a smooth enough surface.

It is possible to fabricate diamonds using several chemicals such as graphite and ferric nitrate by combining them in a pressure cooker.


Tory acquiring the chemicals, as well as a diamond seed, and put them all into a pressure cooker, leaving the mix cooking for three days. However, he failed to create any diamonds.

(This myth was inspired from an episode of CSI: Miami.)

It is possible to fabricate diamonds by covering charcoal with peanut butter and putting it in a microwave.


Kari tried this method but failed to create any diamonds, despite managing to destroy two microwaves.

It is possible to fabricate diamonds using molten graphite and iron by rapidly cooling it and soaking the iron in hydrochloric acid.


Grant performed the experiment but could not find any diamonds.

Explosives can compress graphite into diamonds.


The Build Team was invited to New Mexico Tech to see the demonstration, which used 5,000 pounds (2,300 kg) of explosives. This was the largest explosion ever recorded on MythBusters, producing over twelve times the energy of any previous explosion on the show. After a chemical bath and examination of the results, they did discover diamonds. However, the process only produced low-quality industrial diamonds. While still chemically diamonds, the Build Team agreed that this process was too impractical to attempt at home and that any homemade diamond scheme was implausible.

The act of double dipping is the equivalent of putting the microbes in your mouth into the dip as if all of the dip were put in your mouth.


In their experiment, the MythBusters used chips with regular dip and salsa. In the control test, they put the untouched dip and salsa into petri dishes, and followed with double dipped dip and salsa, and finally dip and salsa that had been put in Adam and Jamie’s mouths. However, when they examined their results, they found that the dip and salsa were already loaded with microbes. For a more accurate experiment, the MythBusters were forced to sterilize all their testing materials with radiation and create a sterile environment. Examining the results, the MythBusters found that double dipping produced less microbes than putting all the dip in your mouth. Also, the amount of microbes present after double dipping was negligible compared to the amount found in regular dip.

(This myth was inspired by the television comedy Seinfeld.)


  1. mark c says:

    just a quick note to grant …

    re banana / make diamonds ep …

    at the risk of stating the obvious …

    diamonds are not rare …

    they may have taken millions of years to form but we both know the earth is billions of years old (unless your a hard core christian) hence the lack of rarity

    if you wanna discuss further email me on above address

    great show


    queensland australia

    P.S. the same goes for gold

    • Alice says:

      Diamonds are not rare, but many companies simply refuse to import diamonds from certain countries because of the miners’ working conditions. Also most diamonds are not of good enough quality to go onto the market.

      • D. Devil's Advocate, Esq. says:

        Companies don’t give a rat’s hinder if workers’ conditions are bad, or conflict minerals wouldn’t be an issue. They restrict supply to maintain prices, you know, like OPEC tries to do, but the diamond market is a tighter cartel.

  2. Dave says:

    on the making of the diamonds with explosives
    the ANFO wasn mixed in with diesel which is a ratio of 16 parts ammonium nitrate / 1 part diesel and a change of 10% of the net weight , so how if it wasnt mixed with diesel did it explode

    • Enrico Martinez says:

      Natural diamonds are rare.

      Synthetic diamonds can now be made with graphite, carbon, some other materials I can not recall. I have seen it somewhere on TV.

      The process is by applying extreme heat and extreme pressure simultaneously. They have added color black to identify it as a synthetic diamond.

      They use these thumb-size synthetic diamonds (lots of it) as teeth for specialized earth-drilling machines to penetrate hard layers of rocks.

  3. preston gross says:

    with banana slip u did not use the same kind of shoes as the peaple in the comedy.

  4. Serena says:

    Testing the “banana slip” with the modern rubber soled boots with a tread would obviously not give the desired result of slipping over in a test as this kind of sole has been developed not to slip. The comedies that featured slipping on a banana peel were from an era when people wore smooth leather-soled shoes which are slippery anyway, especially when brand new. I would like to see this myth revisited useing proper leather soled shoes for accuracy.

  5. Brian says:

    If you put a paper clip in an outlet, extend it with wire and put the other end in a fish bowl, will it kill the fish?

  6. BeamMeUp says:

    In the “double dipping” test, they double-dipped a chip only once. What would the results be if there was a lot of double-dipping, which could occur at a party for instance?

    • Enrico Martinez says:

      I would agree.
      They also have not used a sick person with a communicable disease.
      Adam and Jamie are healthy test subjects and offer little or no conclusive evidence on the double-dipping lab test.

  7. andrew says:

    can a shock from a tazer make a propane tank explode?

    • Jeff says:

      of course not….think about it:the tank is sealed and even if there was a leak it would be too hard to produce enough heat to ignite the propane

  8. andrew says:

    can u make a car explade if u shoot it with a pistel(or other guns)in the gass tank?

  9. Dragonfyre says:

    For the double dipping…
    In comparison to how much bacteria is already in the dip, it’s negligible how many times you do it…it would be gone by the time a noticeable about of bacteria has been transferred.
    And @ andrew: Myth’s already been tested and busted…explosion does not take place, but is plausible if it’s a single shot with a tracer round at a proper distance…it’s on this site in one of the earlier seasons.

  10. James says:

    Serena, thank you for being smart enough to say what I was about to say that they need to wear leather soled shoes and not work boots! They need to re-test that myth other wise they haven’t proved or disproved anything at all!

  11. John K says:

    Do we know where the microbes in the dip and salsa came from?
    Are they in packaged commercial products one can buy at a grocery store?
    If so, maybe a myth to be investigated is the one that commercial products in grocery stores are microbe free.

  12. Sara P says:

    John K, nothing is microbe-free and anyone who thinks food in a grocery store doesn’t have germs in it is very naive. Why do you think you still have to cook meat to 160 degrees? In fact, some foods need bacteria to become what they are (i.e. yogurt). The VAST majority of these bacteria are not harmful.

  13. Charm says:

    We are doing a science project…still, would the saliva in your mouth not be transfered back into the “sharing bowl”? Also, if you eat out of a peanut butter jar, and then put it back in the cabinet…what exactly is the “juicy” stuff that floats atop the peanut butter, if it isn’t bacteria, then what is it???

    • Amanda says:

      that ‘juicy’ stuff would be the separated peanut oil.

    • rose says:

      Its peanut oil!!

    • Chris says:

      Generally, when you double-dip, any saliva on the chip that you dip back into the bowl would transfer to the dip directly next to it… the dip that you then pick up with your chip!

    • Lion queen says:

      Well it would be the peanut oil sepperating for the peanut butter. hope that helps :)

  14. Mark.shifty.lessard says:

    Hello all mythbuster,
    My name is shifty,i’am from saguenay lac st-jean,Québec,canada.I try to understand so many funny ting like you since i was a little boy.Sorry for the english,i’am french,i learn a little bit in the army.The myth about the diamonds is real,so,in realty torry needs 3 weeks to make an industrial diamonds.The method as good so 3 days is insuffisant.you need 3 weeks in this gasous environnement with a thin slice of diamond and 3 weews later you can multiply the thickness by 5 shirly..But that no more spectacular on tv show,i preferd look your way but you say about the myth,BUSTED.That false,the method is good,just WAIT 3 weeks and you got it man.so,i watch religiously all your episod at each time they pass on discovery and dont give-up,i’am a grate fan.

    A mythbuster from french Québec,Canada.!!!!!!!!

  15. Nate L'Armand says:

    I teach physics and love your show because of the wealth of mechanical and experimental ideas you present but the double dipping episode was dissapointing. If someone with an open herpes sore or hepatitus double dipped in the salsa I’d like to see you share their dip. Normal bacteria present in the mouth are not the source of risk. I use this episode to demonstrate the power of experts to mislead and obfuscate.

    • Sevda says:

      It’s possible but only if you took a hit dicertly with in seconds of some one with a cold sore taking one. Herpes doesn’t last long on objects or in open air. It likes direct skin contact with an open sore or blister to be passed on like kissing some one that has a cold sore.

  16. Butane says:

    At Charm: The juicy part that floats is oil from the peanut butter.

    I was sort of disappointed that the banana peel slip was busted. You did slipped, then you call it busted. It feels sort of stupid don’t you think? Its like seeing bees fly but still saying bees could not fly because they have small wings.

  17. colin says:

    Serena summed it up perfectly i would love to see them do it in a pair of rm williams.

  18. Dave H says:

    Guys, regarding the banana peels you need to read the last statement: “banana peels would not guarantee a fall but could still prove to be very slippery on a smooth enough surface.” In other words, their conclusion was the banana peel by itself cannot cause slippage. It requires a set of circumstances. It could be the shoes; it could be what the banana lies on; it could be other “stuff” on the peel.
    The hypothesis is stated this way: “A banana peel on the ground IS GUARANTEED to cause the person who steps on it to slip and fall.” For it to be true, NO OTHER FACTOR would cause you to slip. It’s false; they proved it. If it said: “Banana peels COULD cause a person to fall”, then it’s confirmed.
    BTW, this came from those old black-n-white movies, where everyone slipped and fell on banana peels. It wasn’t ’cause they was slippery. It was SLAPSTICK, and got great laughs. You know what; still does.

  19. Jenny says:

    For the double dipping experiment…

    In the show Food Detective, the host tested whether or not double dipping results in a significant increase in bacteria. Their results show that, compared to the control, the double dipped salsa had a significantly greater amount of bacteria. They did not sterilize their salsa, but factored in the bacteria already present with their control.

    When Mythbusters tested this myth, they mixed the salsa after the testers double dipped. This distributes the bacteria uniformly throughout a large area. When the Food Detectives tested this myth without mixing the salsa, they had completely different results. For guests at a party, the latter method is more realistic. Interestingly, the dipper after the double-dipper would scoop up much of the bacteria left behind from the previous dip, giving the dipper a concentrated dose of bacteria.

  20. blaster says:

    @Dave ANFO is already mixed with fuel hence the name ANFO Ammonium Nitrate Fuel Oil

  21. felixnoir says:

    I have actually slipped on a banana peel! The point is that the banana peel wasn’t fresh; it had been there some days. This makes the white stuff on the inside rot into slime. This was on an asphalt road. The soles of those shoes were rubber: therefore, they stuck to the banana skin (on top) which then slid on the slime. Also, I used to slip all the time on polished lino or tiles wearing (dressage) boots with smooth leather soles. By the way I am very sure footed and have excellent balance – I didn’t fall over, but recovered during the slip.

  22. Andre says:

    There are many microbes that are endogenous or inert to humans, most are destroyed by stomach acids or are crowded out by native intestinal bacterium which are better adapted to survive there.

    That said, I disagree with the conclusion because of one key factor: the human mouth and the kinds of germs it can contain. Hepatitis comes to mind, Streptococcus, Epstein-Barr virus etc that are pathogenic. So sure, it may not be a big bacterial culture, but when it’s nasty germs it doesn’t necessarily matter whether the colony is huge or not.

    As someone who likes to double dip sometimes himself, please be considerate to others and serve yourself your own dip on a plate, for God’s sake.

  23. norway says:

    You would slip on the banana peel if it was raining!!

    • dianna says:

      It happens in the cartoons, I don’t know in reality though…. :)

  24. Enrico Martinez says:

    “The act of double dipping is the equivalent of putting the microbes in your mouth into the dip as if all of the dip were put in your mouth.” is NOT busted!

    You have obviously not seen someone with HEPATITIS share his food or utensils with a healthy person.

    A person who UNKNOWINGLY HAVE HEPATITIS (or other communicable disease) have a high rate of passing the disease themselves to other persons by sharing food (DOUBLE-DIPPING or not).

    There are places on Earth in events like birthdays or other social gatherings, where drinking liquor is done by using and SHARING ONLY ONE GLASS FOR ALL DRINKERS. Healthy people or not, they share only one glass like having a kinship with one another.

    For obvious reasons, Adam & Jamie ARE AFRAID to do this with a sick person, therefore declaring a very much CONFIRMED Myth to be “BUSTED”.

  25. Dennis LeCuyer says:

    Regarding double dipping. I am a Critical Care RN. We deliver TPN (Total Parenteral Nutrition) intravenously. The usual glucose delivered in 4/mg/min. Due to the high level of glucose, the tubing has to be changed daily to avoid growth of bacteria. My question is if a person would double dip in a jar of peanut butter and kept at room temperature, would you not find a growth in bacteria.

  26. Dennis LeCuyer says:

    That is 4mg/kg/min

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