How Lawn Mower Blades Cut Grass (at 50,000 FRAMES PER SECOND) - Smarter Every Day 196

  • Published on Jul 1, 2018
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Comments • 10 713

  • ZetPerson
    ZetPerson Year ago +2385

    At 6:03 my stepdad walked in and told me to go mow the front yard

  • Tazz Shakur
    Tazz Shakur Day ago

    Always wanted to see a lawn mower blade in action thanks

  • mixter7x7
    mixter7x7 2 days ago

    you went out in public with that haircut to demonstrate how a lawnmower works ?

  • Maikeru Kurusu
    Maikeru Kurusu 6 days ago

    If lawn mowers use vacuum to lift the grass up, how does a sythe (dunno if I spelled it correctly) works? Is it just force that cuts the grass?

  • Robert S
    Robert S 7 days ago

    Wow never thought about it that much lol

  • nicolas bourque
    nicolas bourque 10 days ago

    have he ever eard about flo-mo mowers ?

  • HotdogAnd aHayride
    HotdogAnd aHayride 11 days ago

    Actually the tabs and the air flow they create are for waste management and have nothing to do with how the grass is cut. Speed is what cuts the grass. A blade of grass may not have much inertia but there's enough to keep the grass standing upright as it meets an edge moving at 200 mph. String trimmers don't have aerodynamic surfaces or even an edge, yet they still cut grass due to the speed of the string.

  • nukestrom
    nukestrom 12 days ago

    I'm a physicist but I never thought about it before. Nice one.

  • Ashton Raethel
    Ashton Raethel 12 days ago

    Would the same effect happen with a whopper snipper?

  • Scootersnmore
    Scootersnmore 12 days ago

    cool video grass gets a beating for sure and sharp blade look nice even hair cut LOl

  • Karl Fredrik
    Karl Fredrik 13 days ago

    it pains me to say thius. but it's not slow enough

  • Tomar Stevenson
    Tomar Stevenson 13 days ago

    Nice because my mom 😁 like

  • Michael Mebane
    Michael Mebane 13 days ago

    Chainsaw but be safe

  • eceflyboy
    eceflyboy 15 days ago

    At time 8:08 Dustin puts his hands where the no-hand hazard label is and reaches for something.

  • Korree Lukes
    Korree Lukes 16 days ago

    Speed kills

  • Benjamin Esver
    Benjamin Esver 16 days ago

    At 0:04 imagine him just running over children with a lawn mower

  • NMC4114
    NMC4114 18 days ago

    Look at the Scythe and scything grass.

  • RCDai
    RCDai 19 days ago

    What would have been awesome is if you hammered thap tip flap, and tried to use your lawnmower, if it still worked as well

  • harlaf420
    harlaf420 20 days ago

    Question: i use a Flymo mower (yes i am not american)(we dont have a huge lawn), and flymo mowers dont have any wheels. You move them through the fact that it makes a cushion of air for the mower to "float" on, similar to a hovercraft. Wouldnt that mean that the blade pushes air down (there is an air intake at the top of the mower)? Would it mean that it relies on a cutting technique similar to a sickle/hoe(dont know the word, but the tool farmers used to cut grass like waaaay back)?
    Destin the kind of dude that makes people curious about lawn mowers

  • AustinAwsome
    AustinAwsome 21 day ago

    This is the most 'dad' video.

  • Henrik Strand
    Henrik Strand 23 days ago

    My grandfather own a lawnmower that uses opposing blades.

  • Ahmad Zobair Surosh
    Ahmad Zobair Surosh 23 days ago

    I do not understand how does the shape of blade effects the blade to cut the grass?
    Can u help me know it better!
    I appreciate it

  • NobHack
    NobHack 23 days ago

    There is zombie on your lawn

  • Fernando Barela
    Fernando Barela 26 days ago

    I wonder if there's a better way? It's just ripping the grass, and I wonder how healthy it really is for it? It just seems to me that the grass goes through too much trauma. Not that it even cares, but, okay...

  • Dilu
    Dilu 26 days ago

    This might be a dumb question but here in Argentina lawn mowers don't use blade, they used some kind of plastic string (it's usually green), do you think they would work the same way?

  • thousand points of light

    have you ever considered that you're not getting smarter, but you're actually getting

  • Quark Csj
    Quark Csj 28 days ago

    how about 2 opposing blades on the lawnmower

  • Charlie
    Charlie 29 days ago


  • Don Allis
    Don Allis Month ago

    Reel mowers and sickle bar mowers both use a shear motion for cutting.

  • Peter D Morrison
    Peter D Morrison Month ago

    I think it's a bit more complicated than that. The tab can't lift the grass until it has passed over it. The cut is then done by the next blade. At this point there is no more lift, so the cut is made because the mass (inertia) of the grass holds it in place as the blade passes through.

  • Ur boi
    Ur boi Month ago

    6:00 that’s why lawn mowers don’t work as well at high speeds. You drive right past it before the grass has enough time to stand back up.

  • Dwight Hicks
    Dwight Hicks Month ago

    You make her cook for cad

  • Dwight Hicks
    Dwight Hicks Month ago

    It's not science it has nothing to do with air flow it's magic and the barber is a practitioner of the black arts

  • totallyi812
    totallyi812 Month ago +1

    No I have a push mower... no gold
    Spoon here

  • Michael Skoblin
    Michael Skoblin Month ago

    Next, weed whackers, and how they do it.

  • Joseph LaBonde
    Joseph LaBonde Month ago

    A hedge trimmer work at high speed.
    Simple branch trimmer, the curved scissor style ones.

  • Yasad Faizan
    Yasad Faizan Month ago

    How reel mover works... Research paper toro university... Plss describe

  • Dalerobertweese Weese

    When I was very young my dad was still using a non-motor manual-powered "push" mower that used a scissor action. I think they are still being used on golf greens and other places where they want really good quality lawns.

  • Rob Hawkins
    Rob Hawkins Month ago


  • JelloPuddinPops
    JelloPuddinPops Month ago

    Him laying down on the lawn makes me itchy

  • Jason Morrow
    Jason Morrow Month ago

    Talk about the cutting edge of the blades .They are not like a knife edge .Why?


    Using a bolo doesnt have.vacuum effect but can cut grass in the same manner. We just use bolo to cut grass.

  • Pear
    Pear Month ago

    Only Destin gets super excited about a pair of scissors

  • Princern Prince
    Princern Prince Month ago

    How come they don't make a blade that stays sharp longer like a carbide or cobalt blade?

  • nocalsteve
    nocalsteve Month ago

    Dude, your videos are just too long. There’s far too much unnecessary filler and asides. Tighten it up and stop wasting my time.

  • Simon Pruszynski
    Simon Pruszynski Month ago

    A combine harvester is a Good example

  • Max Rabe
    Max Rabe Month ago

    How does a Scythe work?

  • Matthew Smiley
    Matthew Smiley Month ago

    I have a lawn care business!

  • Your sim enthusiast

    No one is wondering half the things this guy wonders

  • Doge The Salty
    Doge The Salty Month ago

    7:15 That moment when your theory that you came up with at the beginning of the video gets proven right

  • Christian Bärtschi

    can you cut off the tips and show the difference

  • John Kavli
    John Kavli Month ago

    now look at the kavli blade see how it works there is a huge difference

  • Gardner
    Gardner Month ago

    I'd love to see a farming equipment series

  • Forgiven Because Of Grace

    How did old time no engine push mowers work ?
    How so whipper snipper/ trimmers cut grass ?

  • Travis Hunt YouTube PhD

    Kinda disappointed he didn't instantly notice the blades would make airflow when the blades have a huge wing like curve on them.
    You can even buy blades with extra airflow design

  • Sandro Bartolini
    Sandro Bartolini 2 months ago

    Great video !
    An interesting double-check experimento would be to modify a blade to obtain a plane blade, without sucking aero effect from bottom to top, as to verify how much of the cutting effect is due to sheer blade speed (and grass inertia) and how much is due also to the lifting effect provided by aero.

  • Hubster
    Hubster 2 months ago

    What about a flymo? They ride on a cushion of air so rather than sucking up the grass and using the wheels to stop the thing vacuuming to the lawn wouldn't they be pushing air down and forcing the grass under the blade then? But they do work as at least in the UK it was if not still is one of the best selling electric mowers.

  • Ian Hamby
    Ian Hamby 2 months ago

    ok i found a 20$ mower at my local Lows but it was just a cylinder with 2 wheels and a handle how does that work if theres no ¨vacuum¨ effect from the blades moving at 200 mph

  • Carl
    Carl 2 months ago

    Why didn’t he call a lawnmower manufacturer???

  • blaster 0416
    blaster 0416 2 months ago

    Do a chain saw. That is interesting how it cuts