This video is sponsored by The Great Courses Plus. Chill: Brew, Brew, I got this whole chicken from the grocery store, but I don’t know how to cook it and I can’t ask for Grill’s help because I want to surprise him with some food. He’s been working so hard on his videos. Brew: Well we’ll need to measure the weight and heat capacity of the chicken first to see how much thermal energy is needed to cook it to temperature. Chill: Uuuhh okay, where’s your scale? Brew: That reminds me, did you know that the internet tried cooking a chicken by slapping it to convert kinetic energy into thermal? Chill: Brew, no no no no. Wa-wait... Brew: Today’s episode covers some theoretical physics. We’re not physicists, but do appreciate a healthy debate with a scientific approach. And, do not try this at home. Most likely, you can’t anyway. And with that out of the way, let’s get into it. October 2018, redditor, Goldenharp_Billy, asked “If kinetic energy is converted to thermal energy upon impact, how hard do you need to slap a chicken to cook it?” Their question went viral with many people trying to calculate the amount of slaps that could generate enough heat to cook a chicken. Parker Ormonde, a physics major, wrote an answer on Facebook: "As your friendly neighborhood physics major, I decided to calculate this with a few assumptions. The formula for converting between kinetic energy and thermal energy 1/2mv^2=mcT The average human hand weighs about 0.4kg, the average slap has a velocity of 11 m/s (25mph), an average rotisserie chicken weighs 1kg (2lbs) and has a specific heat capacity of 2720J/kg*c, and let's assume the chicken has to reach 205 degrees celsius (400F) for us to consider it cooked. The chicken will start off frozen so 0C (32F). 1 average slap would generate a temperature increase of 0.0089 degrees Celsius. It would take 23,034 average slaps to cook the chicken. To cook the chicken in one slap, you would have to slap it with a velocity of 1665.65 m/s or 3725.95 mph.” Aden, a 3D render artist, created a simulation and said that a human—obviously— wouldn’t be able to slap a chicken at 3725.95 mph, but if they could’ve that would decimate the chicken in a violent explosion. Chill: Uhh, that doesn’t look edible. Brew: Not really, no. But that didn’t really stop Youtubers trying to slap the dickens out of these chickens! Youtuber Jake Sing was unable to cook a whole chicken after slapping it for almost half an hour. Mr Bro, also known as Mr Beast’s brother, slapped a whole chicken over 100,000 times. While the colour of the meat on the side he slapped slightly changed, he wasn’t able to get the temperature above 86°F (30°C) Another Youtube channel, Rangers, was also unable to cook the chicken although it did start to dissolve into a gooey mess after 10 hours of slapping. Chill: Eww is that a toilet? Brew: Kyle Hill on Because Science tried explaining energy transfer, and said that even if all the assumptions are correct, the energy could never purely be transferred from kinetic energy to heat. In fact, since you’re pushing the chicken into a surface with the force of a slap that comes from the acceleration of your hand, this hit to the chicken is divided among different modes of kinetic energy into both heat and velocity. He also mentions Randall Munroe’s xkcd what if scenario as an example - you’d never be able to boil water for a cup of tea just by stirring it, since you’d have to stir so quickly with incredible amounts of force, that not only would there be water everywhere, you’d also end up destroying the cup. Youtuber Louis Weisz built a few chicken-slapping machines in order to test out if he could have a more consistent method of slapping the chicken, saying that humans are imperfect. He also said that the math that was done so far didn’t factor in cooling from the environment. Building a motorized chicken slapping device with a hand attached to it, he also tried to retain the generated heat by making an insulated chamber to hold the chicken before giving up on the single-handed machine and instead making a circular slapper that’d be able to beat the chicken in a higher frequency with the attached paddles. Although, that also didn’t work, and for some reason he had entirely abandoned the idea of insulation and heat retention. In the end, like others predicted, the chicken gets squished into gooey pieces before any of the pieces are even remotely cooked. Perhaps they became ... a pink slime? Just like that 3D artist thought! Okay so, while we were editing, Louis Weisz posted a video titled, "I Actually Cooked a Chicken by Slapping It". The video starts promising, with an updated "Meat Beater"; adjustable slap depth, and better control over the slapping surface. Following the suggestion of another YouTuber, JoelCreates, he wraps the chicken with an aerogel insulation material to minimize heat loss. After three failed attempts and many broken parts, he's able to get a chicken's internal temperature up to 45 degrees. Reinforcing the arm and doubling the power output, Louis opts to get a steak up to 40 degrees with a sous vide bath, then used the Meat Beater to bump it up to 60 degrees, cooking it to medium rare and finally eats something. Which gave him hope for the next bird... where details get murky. We do see the beginning of the slapathon, but for the first time, aren't shown the initial temperature. Louis says he's sustained almost 90 minutes in keeping the chicken at a minimum of 55 degrees celsius, when the joint holding the rig started breaking. Louis then shows a chart saying the chicken is cooked, but looking carefully, the chart is for poultry breast and thighs, not a whole chicken. In fact, earlier in the video he claims that sustaining at 55 degrees would kill bacteria necessary to "pasteurize" the chicken, but according to the FDA, 74 degrees of internal temperature is considered cooked, and safe to eat. Louis then tries distracting his audience by saying that the main reason he didn't end up eating the chicken was that it got contaminated due to the insulation material with fibreglass and aerogel leaking into the meat. So it's safe to say that no, Louis actually DID NOT cook a chicken by slapping it like his video title and content suggests. But hey, kudos on cooking that steak. And you know who else didn’t cook that chicken? Me! I built a hydraulic arm— Chill: Wait, wait, wait. You like, made a hydraulic arm? Have you like been watching some engineering Tiktoks or something? Brew: What do clocks have to do with this? Chill: Guess not. Brew: But no, The Great Courses Plus is where I learned how to build this little mechanical wonder! While we were working on this episode, I just had to throw together an experiment. Which, uh, didn’t turn out to look particularly appetizing. Chill: They have courses on that? Brew: You bet! Browsing the vast library of on-demand courses provided by professors from Ivy League universities, and experts from institutions like National Geographic and The Smithsonian, I found a course on DIY Engineering by Stephen Ressler, PhD. I’ve enjoyed learning how to construct cardboard towers, miniature suspension bridges, and yes, even hydraulic arms! For my next project, I might just build a ballista for Howard. Long range coffee delivery is within my grasp… Click the link in the description and sign up now at TheGreatCoursesPlus.com/Brew to get a free trial for this wealth of knowledge. But I’m not the only one who decided to test different forms of kinetic energy. 1987, Tucson Arizona. Researchers Gimmi and Browne from the University of Southern Arizona decided that they wanted to test out cooking a 25-pound turkey by using potential energy, claiming that since wood and fossil fuels are limited resources, alternative non-combusting energy sources were needed to ensure that civilization could continue, and that “The obvious solution to any future energy crises is the development and use of potential energy. This form of energy is ubiquitous in nature, it is renewable; and, to date, it has largely been untapped.” Their explanation on how this would work was that all elevated objects possess potential energy, that would be converted into kinetic energy when dropped. This energy then would be converted into heat upon impact with the ground, that can be described with the energy balance equation. So, to test it out, they bought a 25-pound (11.3 kg) turkey that they defrosted, along with some bananas to bribe an undergrad, and climbed on top of the administration building’s 10th floor at 9 am in the morning to start the most inefficient experiment ever. Flinging the bird carcass off a ledge on the building, the undergrad would have to run down 10 flights of stairs while the investigators took the temperature of the turkey. After grabbing the turkey from the concrete ground, the poor assistant would have to run all the way back up and throw the bird down again. This went on until 3pm in the afternoon, 6 hours after they’d begun their experiment. During this time, the turkey was dropped a total of 72 times, and the internal temperature had gone up 33 degrees Fahrenheit—from 32 to 65 degrees. They also noted that the ambient temperature was 68 degrees Fahrenheit, which surely contributed to the heat transfer, since we don’t live in a vacuum chamber. The reason they halted the experiment was because they ran out of bananas they had bought to bribe the undergrad, who I’m sure was sick of running up and down anyway. According to their calculations, the turkey would’ve reached a temperature of 400 degrees Fahrenheit in approximately 46 hours, and that while this was “admittedly a slow cook,” they hadn’t burned any fuel, and upon the principal investigator trying the turkey, he remarked while it was “somewhat cool, it was comparable to any of the cooking his spouse had done at home”, and that “the meat was very tender”. Chill: Ew, but Brew, that’s a turkey, and I can’t throw— Brew: Absolutely, so how does that apply to your chicken? Well, a chicken is lighter than a turkey, so the potential energy of it would be less as well. The formula for calculating potential energy is the multiplication of the object’s mass, the gravitational field strength, and height, so the decrease of mass— Chill: Brew we’re not going to eat sidewalk chicken! That’s a yuck not yum! Brew: Oh. Okay so what if instead of dropping the chicken, we launched it off by applying some force— like catapulting it? While human athletes can reach an initial velocity of 145 km/h for throwing, machines are better than humans. So, what if we launched our chicken with the greatest trebuchet ever built? Chill: Uhh, Brew… Brew: Meet the Ludgar War Wolf, the Bugatti of medieval siege weapons. Commissioned by King Edward I during the siege of Stirling Castle in the year 1304, it was the largest trebuchet that ever existed. Reportedly, it required the crafting skill of 5 master carpenters and 49 laborers to complete this formidable fear engine. In fact, even laying eyes of the size of such a weapon was enough to compel the defenders of Stirling Castle to surrender, to which the King responded: "hahahaha trebuchet go brr" The Warwolf sprung into action despite the surrender, so that the assembled crowd didn’t have to leave disappointed. Edward’s wife, Margarete even had a custom made tower with a viewing balcony. The trebuchet was capable of hurling heavy boulders up to 300 pounds at a speed of 120 miles per hour. and the castle didn’t hold out for long. At the end of the first and only time it was used, only 30 people survived the siege. Now, before we get to how fast we can launch our 2-pound (~1 kg) chicken with an initial velocity of 120 mph (190 km/h), we need to build our trebuchet. In order to make a historically accurate representation— Chill: Brew, all of these things are physically impossible for me to accomplish! And you talked so much that I ran out of time—Grill’s already on his way back! Brew: Oh, why didn’t you say so? Well, our fourth cooking method is probably just ordering it off Hillside Eats. That’s what I usually do. Chill: But we already have the chicken. And it’s definitely thawed by now. Grill: Ayy I’m back! Did Brew trap you in one of his episodes again? Chill: Grill - I don’t want to build a trebuchet! Grill: Dinner is served. Aand, if you wanna know more about chicken than anyone should ever know, click the video on your screen to watch the 3-part series I made about the wacky world of Colonel Harland Sanders’ Kentucky Fried Chicken, on my channel, Grill. Did ya know that he shot a guy once? True story!
