How hard do you need to slap a chicken to cook it?

[GuitarStv]

Settle a bet.  I'm pretty sure that your hand has to be moving at close to mach two when you hit the chicken.  Based on:



Thermal Energy Equation
Q = mc(T1 - T2)

Q = thermal energy
m = mass of object
c = specific heat
deltaT = desired temperature change

- The safe internal temperature of a cooked chicken is 75 degrees C (https://www.thekitchn.com/the-right-internal-temperature-for-cooked-chicken-quick-kitchen-facts-216074).  Let's assume that we're starting with a chicken from the fridge.  Average fridge temperature is 1.6 degrees C (https://lifehacker.com/what-temperature-should-you-keep-your-refrigerator-set-533534221).  So T1 - T2 = 75 - 1.6 = 73.4 degrees C

- Average weight of a chicken is 1.8 kg (https://www.quora.com/Whats-the-average-weight-of-a-whole-chicken) so m = 1.8 kg

- The specific heat of a broiler chicken is 3.22 kJ/kgC (https://www.engineeringtoolbox.com/specific-heat-capacity-food-d_295.html) so c = 3220 J/kgC


Therefore the energy needed to cook a chicken through kinetic energy is:
Q = mc(T1 - T2)
Q = 1.8 * 3220 * 73.4
Q =  425426.4 J


The number above is the amount of energy you need to deliver in the slap . . . but that's hard to picture.  Let's find out how fast your hand has to be moving to cook the chicken . . . which I think is closer to what you really want to know.  So we'll pull out another grade 9 physics formula . . . the one for kinetic energy:

Kinetic Energy Equation:
E = 1/2 mv^2

E = kinetic energy
m = mass of the object moving (in this case your hand)
v = velocity


Now let's re-arrange the equation to solve for v:
2E = mv^2
2E/m = v^2
v = (2E/m)^.5


- We already calculated the amount of energy necessary:  425426.4 J
- The average weight of a human hand is .41 kg (https://journals.sagepub.com/doi/abs/10.1177/154193128603000417).  So m = 0.41 kg.


v = (2*425426.4/0.41)^.5
v = 34,8849.65^.5
v = 590 m/s

The speed of sound is 343 m/s, so you would need to hit the chicken with your hand at roughly twice that speed (mach 2) . . . this leaves a little margin of error with the chicken temprature for losses due to other things (like the exploded bits of chicken bouncing into soft drapes/carpet and losing some energy).


Double check my math and assumptions, but I think this is the correct answer.

[SunnyDays]

That's funny.  For some reason, my brain read "to kill it" and my immediate thought was "are you holding an axe or not?"  Better go get more sleep.

[RetiredAt63]

Cooking is best if energy is evenly applied. If you could get enough energy with a slap, wouldn't the slapped side be overcooked and the non-slapped side be undercooked?

Who the hell thought up this scenario, and what were they high on?

[GuitarStv]

Cooking is best if energy is evenly applied. If you could get enough energy with a slap, wouldn't the slapped side be overcooked and the non-slapped side be undercooked?

Who the hell thought up this scenario, and what were they high on?

There may be an issue of uniformity of cooking . . . the part of the chicken that your hand first contacts will receive the most heat. I suspect that as the shockwave from the blow liquidizes the chicken that the heat will travel quite rapidly to the remaining pieces though. Either way, that's why I said mach 2. That's got a built in margin of error . . . so there should be some excess energy to avoid undercooked chicken liquid (vapor?).

[MrMoogle]

You're assuming all your kinetic energy from your hand is transferred to thermal energy in the chicken.  This is not true.  A lot of energy will stay in your hand.  A lot of the transferred energy will become kinetic in the chicken.  Also at these speed, you'll waste energy as you tear the chicken apart. 550m/s is the low end of the speed of a bullet.  I don't know how to quantify any of these things :)

[GuitarStv]

So, you think a second slap would be required?

[BussoV6]

Step away from that joint, sir!

[EvenSteven]

So, you think a second slap would be required?

I think it would be more effective to do a simultaneous double slap with the chicken in the middle. More like a clap.

[dandarc]

This sounds like a question for XKCD.

[Daley]

So, you think a second slap would be required?

I think it would be more effective to do a simultaneous double slap with the chicken in the middle. More like a clap.

Yes, I believe slapping the chicken simultaneously with both hands, each traveling at mach two with a collision trajectory between them would suffice. A double slap.

[robartsd]

This sounds like a question for XKCD.

Yes, I'm sure I'd enjoy Randall Munroe's take on this in the "What If?" section

Reminds me a bit of a video I saw recently in which they attempt to cook a turkey with thermite.

[solon]

The title question sounds vaguely... dirty.

[scottish]

I think it will cook your hand before it cooks the chicken...

[GuitarStv]

I think it will cook your hand before it cooks the chicken...

Let's assume as an initial condition that my hand is sufficiently calloused to survive the speeds necessary.

[bacchi]

So, you think a second slap would be required?

I think it would be more effective to do a simultaneous double slap with the chicken in the middle. More like a clap.

Yes, I believe slapping the chicken simultaneously with both hands, each traveling at mach two with a collision trajectory between them would suffice. A double slap.

If the hands met, they'd splatter chicken everywhere. That's fine if you want chicken stew but not if you want to eat a chicken breast.

But maybe that's what you meant when you stated a collision trajectory between them? The hands stop at a point before meeting based on the width of the chicken.

[Financial.Velociraptor]

Do we assume a friction-less and spherical chicken in a zero gravity environment?

[edit] - Also, Chuck Norris is the only living human who could cook a chicken this way.

[Daley]

So, you think a second slap would be required?

I think it would be more effective to do a simultaneous double slap with the chicken in the middle. More like a clap.

Yes, I believe slapping the chicken simultaneously with both hands, each traveling at mach two with a collision trajectory between them would suffice. A double slap.

If the hands met, they'd splatter chicken everywhere. That's fine if you want chicken stew but not if you want to eat a chicken breast.

But maybe that's what you meant when you stated a collision trajectory between them? The hands stop at a point before meeting based on the width of the chicken.

Absolutely. The key is to rapidly compress the chicken to heat it, ideally to the point just short of explosion.

[GuitarStv]

Guys, these theories are well and good . . . but where's the math to back 'em up?

[Daley]

Guys, these theories are well and good . . . but where's the math to back 'em up?

I'm more of an... idea man, so I had the guys down in accounting work out the details and they sent this back. I'm sure it all checks out fine, and they tell me that what you're looking for can be found in Table S1 on the attached file.

[Boofinator]

Settle a bet.  I'm pretty sure that your hand has to be moving at close to mach two when you hit the chicken.  Based on:



Thermal Energy Equation
Q = mc(T1 - T2)

Q = thermal energy
m = mass of object
c = specific heat
deltaT = desired temperature change

- The safe internal temperature of a cooked chicken is 75 degrees C (https://www.thekitchn.com/the-right-internal-temperature-for-cooked-chicken-quick-kitchen-facts-216074).  Let's assume that we're starting with a chicken from the fridge.  Average fridge temperature is 1.6 degrees C (https://lifehacker.com/what-temperature-should-you-keep-your-refrigerator-set-533534221).  So T1 - T2 = 75 - 1.6 = 73.4 degrees C

- Average weight of a chicken is 1.8 kg (https://www.quora.com/Whats-the-average-weight-of-a-whole-chicken) so m = 1.8 kg

- The specific heat of a broiler chicken is 3.22 kJ/kgC (https://www.engineeringtoolbox.com/specific-heat-capacity-food-d_295.html) so c = 3220 J/kgC


Therefore the energy needed to cook a chicken through kinetic energy is:
Q = mc(T1 - T2)
Q = 1.8 * 3220 * 73.4
Q =  425426.4 J


The number above is the amount of energy you need to deliver in the slap . . . but that's hard to picture.  Let's find out how fast your hand has to be moving to cook the chicken . . . which I think is closer to what you really want to know.  So we'll pull out another grade 9 physics formula . . . the one for kinetic energy:

Kinetic Energy Equation:
E = 1/2 mv^2

E = kinetic energy
m = mass of the object moving (in this case your hand)
v = velocity


Now let's re-arrange the equation to solve for v:
2E = mv^2
2E/m = v^2
v = (2E/m)^.5


- We already calculated the amount of energy necessary:  425426.4 J
- The average weight of a human hand is .41 kg (https://journals.sagepub.com/doi/abs/10.1177/154193128603000417).  So m = 0.41 kg.


v = (2*425426.4/0.41)^.5
v = 34,8849.65^.5
v = 590 m/s

The speed of sound is 343 m/s, so you would need to hit the chicken with your hand at roughly twice that speed (mach 2) . . . this leaves a little margin of error with the chicken temprature for losses due to other things (like the exploded bits of chicken bouncing into soft drapes/carpet and losing some energy).


Double check my math and assumptions, but I think this is the correct answer.

A quick check of your calcs shows what seems to be an error on the second-to-last line. I get

v=2,075,249^0.5=1,441 m/s~mach 4.2

But as others have noted, converting that kinetic energy to thermal energy is a different challenge.

A couple more things to consider: When cooking, chemical changes take place, and if I had to make a guess, these are often endothermic. Also, steam is often given off, and this latent heat wouldn't be accounted for either.

[APowers]

For more even cooking, why slap it only one extremely hard slap? Why not 100 slaps, evenly distributed at much lower velocities? or 1000 slaps?

[markbike528CBX]

This sounds like a question for XKCD.

Yes, I'm sure I'd enjoy Randall Munroe's take on this in the "What If?" section

Reminds me a bit of a video I saw recently in which they attempt to cook a turkey with thermite.

Steak drop https://what-if.xkcd.com/28/   TL;dr  - Mach 6 into air from space is not enough.

[seattlecyclone]

This sounds like a question for XKCD.

Yes, I'm sure I'd enjoy Randall Munroe's take on this in the "What If?" section

Reminds me a bit of a video I saw recently in which they attempt to cook a turkey with thermite.

Thank you for this link. I laughed out loud through most of the video.

[GuitarStv]

Settle a bet.  I'm pretty sure that your hand has to be moving at close to mach two when you hit the chicken.  Based on:



Thermal Energy Equation
Q = mc(T1 - T2)

Q = thermal energy
m = mass of object
c = specific heat
deltaT = desired temperature change

- The safe internal temperature of a cooked chicken is 75 degrees C (https://www.thekitchn.com/the-right-internal-temperature-for-cooked-chicken-quick-kitchen-facts-216074).  Let's assume that we're starting with a chicken from the fridge.  Average fridge temperature is 1.6 degrees C (https://lifehacker.com/what-temperature-should-you-keep-your-refrigerator-set-533534221).  So T1 - T2 = 75 - 1.6 = 73.4 degrees C

- Average weight of a chicken is 1.8 kg (https://www.quora.com/Whats-the-average-weight-of-a-whole-chicken) so m = 1.8 kg

- The specific heat of a broiler chicken is 3.22 kJ/kgC (https://www.engineeringtoolbox.com/specific-heat-capacity-food-d_295.html) so c = 3220 J/kgC


Therefore the energy needed to cook a chicken through kinetic energy is:
Q = mc(T1 - T2)
Q = 1.8 * 3220 * 73.4
Q =  425426.4 J


The number above is the amount of energy you need to deliver in the slap . . . but that's hard to picture.  Let's find out how fast your hand has to be moving to cook the chicken . . . which I think is closer to what you really want to know.  So we'll pull out another grade 9 physics formula . . . the one for kinetic energy:

Kinetic Energy Equation:
E = 1/2 mv^2

E = kinetic energy
m = mass of the object moving (in this case your hand)
v = velocity


Now let's re-arrange the equation to solve for v:
2E = mv^2
2E/m = v^2
v = (2E/m)^.5


- We already calculated the amount of energy necessary:  425426.4 J
- The average weight of a human hand is .41 kg (https://journals.sagepub.com/doi/abs/10.1177/154193128603000417).  So m = 0.41 kg.


v = (2*425426.4/0.41)^.5
v = 34,8849.65^.5
v = 590 m/s

The speed of sound is 343 m/s, so you would need to hit the chicken with your hand at roughly twice that speed (mach 2) . . . this leaves a little margin of error with the chicken temprature for losses due to other things (like the exploded bits of chicken bouncing into soft drapes/carpet and losing some energy).


Double check my math and assumptions, but I think this is the correct answer.

A quick check of your calcs shows what seems to be an error on the second-to-last line. I get

v=2,075,249^0.5=1,441 m/s~mach 4.2

But as others have noted, converting that kinetic energy to thermal energy is a different challenge.

A couple more things to consider: When cooking, chemical changes take place, and if I had to make a guess, these are often endothermic. Also, steam is often given off, and this latent heat wouldn't be accounted for either.

Dammit.  I think you're right.

[GuitarStv]

For more even cooking, why slap it only one extremely hard slap? Why not 100 slaps, evenly distributed at much lower velocities? or 1000 slaps?

Who has time to spend the whole day slapping a chicken?

[EvenSteven]

For more even cooking, why slap it only one extremely hard slap? Why not 100 slaps, evenly distributed at much lower velocities? or 1000 slaps?

Who has time to spend the whole day slapping a chicken?

Isn't this why we all aspire to FIRE?

[GuitarStv]

:D

[Milkshake]

https://www.boredpanda.com/physics-major-calculates-how-hard-to-slap-chicken-to-cook-it/?utm_source=google&utm_medium=organic&utm_campaign=organic

[GuitarStv]

Huh.  He used a different heat capacity and started from a different temperature, but came to roughly the same conclusion that I did (well, ignoring the math mistake in the OP).  I'd have figured there would be more variation between answers.

[dandarc]

Huh.  He used a different heat capacity and started from a different temperature, but came to roughly the same conclusion that I did (well, ignoring the math mistake in the OP).  I'd have figured there would be more variation between answers.

His chicken will also be burned to an inedible state. 400 degrees? I mean, you set the oven to roughly that temperature, but you don't leave the chicken in so long it also gets up to 400 degrees.

[frugalnacho]

This topic has been discussed at length all over the internet.

https://knowyourmeme.com/memes/slaps-chicken-at-327595-mph

[GuitarStv]

This topic has been discussed at length all over the internet.

https://knowyourmeme.com/memes/slaps-chicken-at-327595-mph

I was actually unaware of this . . . and will have to have some words with a friend of mine.

[frugalnacho]

This topic has been discussed at length all over the internet.

https://knowyourmeme.com/memes/slaps-chicken-at-327595-mph

I was actually unaware of this . . . and will have to have some words with a friend of mine.

You are one of the lucky 10,000 today. 

https://xkcd.com/1053/

[Dragonswan]

Go ask Barry Allen over at Star Labs.

[aetheldrea]

I will usually slap a 6 pound bird a couple minutes at 200-300 mph to cook it through completely. I find it best to stay below 600mph so you can get away with just a face shield instead of having to put on the blast suit, and the neighbors complain less about the sonic booms.

It also works good to gently tap it few times to get its natural vibrating frequency, and then scream that note really loud, like 400 decibels or so, and that will cook it deep inside. Hearing protection recommend.

Drizzling it with a melted stick of butter and sprinkling it with a mixture of oregano, thyme and salt before cooking adds a nice touch.

To get the skin nice and crispy, I just blow on it real fast, maybe 20,000mph, and then the friction of the air molecules cooks it like a meteor. Works best if you make a “hot” exhale by raising the tongue near the back of your mouth. Also make sure you give the National Weather Service a half hour or so notice so they can issue their tornado warnings.

YMMV

[electriceagle]

A couple more things to consider: When cooking, chemical changes take place, and if I had to make a guess, these are often endothermic. Also, steam is often given off, and this latent heat wouldn't be accounted for either.

This.

The USDA says that the water content of a chicken fryer decreases from 66% to 60% upon cooking (https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/meat-preparation/water-in-meat-and-poultry/ct_index)

Given the original poster's 1.8 kg chicken and the assumption that the lost water evaporates away, this requires evaporating 108 g of water. The enthalpy of vaporization for water is 40650 J/mol. One mole of water weighs 18 grams. Thus boiling the water in one such chicken should require about 2.4*10^5 J. The original post listed 4.2*10^5 J for heating, so we have a total of 6.4*10^5 J.

However, we have not yet considered the main reason that we cook food: to denature proteins. This serves to make the chicken easier to digest and to kill bacteria and other organisms that are inside the chicken. For more: https://onlinelibrary.wiley.com/doi/full/10.1111/1541-4337.12243

I will leave the protein denaturation energy requirement estimate as an exercise to the reader.

By the way, I like the vibration idea. It could be quite efficient, depending on the size of the chamber used.