I explore the world using science. That's pretty much all there is to it. Watch 2 videos. If you learn something AWESOME, please subscribe if you feel like I earned it.
Contact: www.smartereveryday.com/contact. I currently get lots of correspondence so please forgive me if I'm unable to reply. I mean well, but want to focus on being a better Dad.

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  1. Derek Jackson

    It is not a heat affected zone so much as a stiffness discontinuity and thus stress concentration for the fence. Also the line is getting a curved beam bending effect plus shear and tension which all combine into a max principal strain.

  2. Raeef Islam

    Spaghettification is now an official word

  3. STRtracer 3

    Your that guy and the youtuber

  4. Yung Padawan

    It's funny you've never considered the line length and engine torque demand. I worked on them while in high school at a small engine repair shop. I always had to tell customers not to remove their guards and also to try and keep the line at its longest length. Reason being if the line is run too short you can actually over speed the engine. If you do it for an extended period of time it can slowly destroy the engine. That was far less common than the other problem though. Most would remove their guards and then come in with a heavily worn engine. Even though it was less than a few months old. It was because they had such an excess load on the thing at all times, it was destroying itself. Not just the engine but the actual shaft and all the bushings and bearings would be so worn from this too. The cutter that regulates the length of the cutting chord not only keeps the engine from over speeding but it keeps the string the same length. Which makes the rotating force much more evenly distributed among the bearings. So if one side of the string is longer than the other, it will destroy the bearings and gears that drive the head.

    1. Yung Padawan

      To be clear. I didn't mean it's funny you've never thought of that, as an insult. I merely mean it's funny because of the fact I think about it immediately when someone tells me about a problem with these tools. Since I had to deal with so many different failures and problems with them. You find out a lot about the engineering behind these machines. It truly does make me grateful for the amazing minds behind even the simplest of machines. Without these fail safes, we wouldn't have the convenience we do today.

  5. Steve Reith


  6. Mr. Atrophy

    I have a request , I have always been fascinated with the Taylor-Couette flow experiment. the flows bifurcate in this experiment, over and over till an instability forms and a predictable flow become chaotic , how would this look with your camera ?

  7. Gardeners' Farmacy

    WHAT??? No leg slap close up??? You've done me no justice. I wanted to see what happened that one time i messed up. Ok maybe twice. But that one time, it really got my attention for a few days. That booboo was badbad.

  8. Joshua Cantin

    Seeing the line and the wire in slow motion just makes my intuition as to what the line is about to do just feel off :P That is, I almost feel as if the line is acting as if it were much denser than it appears. That is, it appears in the slow mo video to be moving slowly and thus with low kinetic energy, but its behaviour is as of with something with high kinetic energy; thus, the line intuitively feels much heavier. Is there actually a way to come up with an effective density such that if we took a line with the effective density but at the speed it appears in the video, the physics is the same? I am thinking of something similar to that used when scaling down ship models to table top sizes. That is, is there a scaling relationship that we could use to see the same physics without needing to go to high speed?

  9. Anas life and times

    while you've got the camera out, maybe show how I managed to whack a hole in a 5 gallon plastic bucket, which leaks now;)


    The fine gentleman at project farm has done some weed eater line testing too. Results were very interesting.

  11. Minuka Rodrigo

    Weed eaters have a metallic string at the bottom right?

  12. Not Justin Y


  13. Dap P

    You should also check out different types of lines!!!

  14. Prototheria

    1:20 Neighbors looking over the fence: "Why's he talking to his weed eater?"

  15. Keegan Moore

    Receive the G’s.

  16. John S

    Also it's not called a weed eater. Or a weed wacker. It's called a *Whipper Snipper*

  17. John S

    It's 2020 and you're still not using low E guitar strings as cutters? That's embarrassing dude.

  18. Jakers

    Literally just beats the snot out of grass

  19. MY1PATH

    I like how you put the stickers on the trimmer. I almost didn't notice them because I was so focused on the line lol

  20. twinturbostang

    7:45: My allergies are acting up just looking at this.

  21. zmaud

    Ugh just use milimetres or μm..... no one can understand 69420ths of an inch

  22. James Timothy Wier

    Hey do you want to learn about cotton next

  23. Derek H.

    I always file out the hole and run 1/4 inch square. That’s what the big walk behind weed eaters usually use. That’s what I think works best. Lots of berry vines where I live, it eats them up.

  24. Jesse Crotts

    I may be wrong, but I thought that it voids a patent if you publicly announce your patent idea???

  25. Enrique Boah

    How weed eaters work: 3.4M people: hmmm interesting

  26. Jason Stechman

    First off I’d like to say I really enjoy your channel, and so I saw this video last night and during the middle of it you interviewed General Brown. That was pretty cool for multiple reasons one being the access you were allowed but secondly was he was my Brigade commander at Fort Lewis at the 1st Stryker brigade and during our deployment. Pretty cool.

  27. King beef

    Ooooohhh that's where the noise comes from

  28. Joe Erler

    Which model is your Leatherman? Wave or Surge?

  29. Nathaniel Wilzer

    It’s a weed whacker not a weed eater 🤦‍♂️

  30. Panamera Ghost

    My electric weed eater has only one line. It never bothered me when I first bought it.

  31. Bikepaddle

    Loved the video...which is typical... keep it up! I have one request... please add metric. 110-112 thousandths... 95 thousandths of an inch... Please man....2 point something millimeters.... what exactly is the measurement... We love you in Canada. In the follow up I'd also love to see what the high-speed looks like when weed-eating around landscaped rocks or other solid objects.. maybe top view? I have doubled the cord in these situations which helps but I really wanna know what happens with a typical weed-whacker. Thanks Dustin, love the content.

  32. Jennifer Reeves

    I do feel bad for the kitties, but I'm definitely reassured by the fact that they don't seem upset at the humans afterward

  33. jUst a raNdom sTranger

    I just found out your channel few days ago and now i'm addicted to your videos..nice content man, this is how you upload vids and not those scripted "pranks" other youtubers uploaded :)

  34. Watch Hill

    Hiya Dustin. You earned my sub a few weeks ago with your 'Snatch Blocks" video. One of these days, when I have that magic thing called "disposable income", I'll be a patron. For now, thanks for making scientific concepts fun.

  35. TROLLZOR808

    We are so close to getting the wonder waffle IRL

  36. Lana Gray

    Well I never thought I'd watch a 20 min video on someone cutting grass but here I am

  37. Der Hutmacher


  38. Austin Atkins

    Smart guy, you bought a stihl 👍

  39. nzoomed

    11:25 look at all that micro plastic being created!

  40. Tim Pierce

    👍🏼👍🏼👍🏼: how about a video engineering and making/cooking/baking food

  41. chris brinkley

    I thought this was going to be about Joey Diaz

  42. Candid Gamer

    Destin: it seems like the water is hydrophobic Dumb me: wait, that's illegal


    11:58 Wacky waving inflatable arm flailing tube man

  44. James Fallon

    I love that you can hear the individual cylinder strokes of the weed eater engine. Very cool.

  45. Matthew Schultz

    Guess I have to up my patreon support since I already subscribed and support. I like the pause.

  46. Pretentious Bear

    Knew it, how weed eaters work oh its smarter every day its going to be a drawn out 20 minute video where he tries to make some huge life discovery, ill pass.

  47. Jonathan Maxwell

    This is the biggest NERD thing I've EVER watched on YT. and I LOVE IT!

  48. RandomGamerOS

    "the raycons are the most interesting to me because they got this iddi bity case that charges them" Apple airpods: am i a joke to you?

  49. Ben Plays

    I can’t believe I’m interested watching people cut grass

  50. Getbaccgang

    I thought sum was on my screen when the birds went by😂😂😭1:27-1:30

  51. bobbycone2

    Crazy to think that all those little bits of plastic are going into the ground every time we do this. Need some biodegradable weed eater line.

  52. bsandy.com

    I used to build airplanes in Brazil, later biomedical units in Florida; 30 years later the Brazilian airplane assembly line moved to Florida as well. So, the creative and industrial process is really amazing. I watched this video twice, it was entertaining once again. I still don't know how the rockets avoid the elephants and turtles supporting the Earth on the way out. :-D

  53. Bush Hippie

    As a guy who works with a weed whacker on a bi-daily basis, this video was so cool!

  54. Trick3y BIGHOUSE

    I thought ALsel had a 60 frame cap

  55. Galaxy Gang

    Ever thought of g force? Straightening the cord ?

  56. Jonny B

    Love that you put a bible verse at the end of your videos . especially being a scientific person.. Luke 14:11 those who exalt themselves shall be humbled, and those who humble themselves shall be exalted...

  57. B Donough

    The reason you see ten booms Me an intellectual: that’s not how this works

  58. Alexander Gen

    Love the cat in the background

  59. LlamabenGG Ahaha

    Why do you have your finger on the trigger that is very dangerous even if it is not loaded

  60. LlamabenGG Ahaha

    Why do you have your finger on the trigger

  61. Dakota Dirden

    SNATCH BLOCK!! bro it’s awesome lol

  62. Blubyrd Racing

    Why did I hust spend 20 minutes watching a video about a weed eater 🤣

  63. camrillem

    How was the sponsor not Snatchblock?!??,

  64. Electro Cute

    Destin breaks his wrist in slo-mo

  65. David L.

    Gee, Destin this is Amazing!!!!!

  66. Dr.TreVlogs

    When the weed eater caught the wire

  67. Bryan Rivas

    Hate this guy

  68. dragon bite art

    18:36 if you would like to chi that video

  69. David Rutherford

    I read that yo

  70. admiralcapn

    Destin: "I've been weed-eating for years." Me: Man, Hello Fresh is really starting to mess with their spokes-people.

  71. angry energy

    ngl i thought this was about pot

  72. pierre okkes


  73. Mint

    I watch 1 Mark Rober video and now this is in my recommended

  74. MerGe Flawless

    It whacks weeds, it doesn't eat them....

  75. William Schloendorn

    He needs to sharpen the cutter blade and it will cut on the first contact!

  76. Manny Lemus

    Video is way too long

  77. Miles The Man

    Why did the chicken cross the road? W E E D E A T E R

  78. David Rutherford

    I trim right to left as well but also walk backwards. Keeps the trimmer from throwing debris back on me.

  79. Dave Russ

    Weed wacker?

  80. Illumina09

    A smart phone has more processing power than the controller for Saturn V rocket. Think about that . . .

  81. pengudyst

    You do know ur putting thousands of tiny cuts on ur hands

  82. deathbykindnes

    Weed Eater is also a great band

  83. Stalkyard

    wth is 99 thousands of an inch. just give me milimeters lol

  84. Jere RGF

    You could just be one of the people ti walk in your shed and make us discover stuff we never thought about

  85. taiyoctopus

    6:27 getting allergies just looking at that lol

  86. Caliber Gold

    I usually call it string trimmer or weed wacker

  87. pengudyst

    It's pronounced mozin

  88. hunter

    You should break a bottle on the shleiran camera to see if anything happens

  89. Nathan Kahla

    Would love a how chainsaws work in super slowmo. How different depths of chain gullet effect chainsaw cutting speed. Love your videos, thank you!

  90. coleh46

    Bruh, who on planet earth says “weed eater”? That makes you literally upset

  91. Lizzy Kehlor

    Cant you just go straight on the bike

  92. Jamis Rose

    Weed WACKER gang where ya at?

  93. Tuffy

    Weed whacker

  94. Mita Skeledzija

    Thanks for this video! I always wondered how they work 😂

  95. MoltenPepsi

    Ughhh I hate how the water is getting his jeans wet

  96. Almost Oem Auto

    Go find georgey and help him for like a week he's so cool

  97. • Rock’tober •

    seeing two brilliant engineering guys scream “woah” is childish wonder is amazin

  98. Pedro Gómez

    Hey, cool video! I got intrigued about the sound. It seems to me that is added on post, but I wanted to check if that's the *real* sound of grass being cut in slomo. thanks!

  99. Riley

    We call it a whipper snipper in Australia

  100. Chris

    Destin subbed to mark when he was at 10k subs, and destin was at 600k subs. Destin is at 8 million subs and Mark is at 12 million. Time flies