The Physics of Car Crashes 

“Speed has never killed anyone. Suddenly becoming stationary, that's what gets you.” ― Jeremy Clarkson

Thanks for using metric units!

This is really cool. A good way to counter the people who say that "cars were better back in the day"

Doing a joke about petrol would be fuelish

Crunchiness is something that good cars and good candy bars have in common.

Hooray for sperm teaspoons!

this is why the tesla model S has such a good safety rating. with no engine in the way, the entire front section is a huge crumple zone

And what about side crashes?

I liked the part about how inneficient fuel engines are... that's crazy.

Another technique is that the engine is designed to be deflected down under the safety cell. This is good for 2 reasons. The first is that the engine is pretty solid and can't be compressed. The second is that the engine is heavy but by deflecting it down under the car it doesn't have to decelerate gently and the crumple zones don't need to worry about absorbing all that energy. Let the engine hit the tree and come to a dead stop while the car is "gently" decelerated by the crumpling above it.

Your last point is excellent. A dent or crease in the wrong place can dramatically reduce the yield strength of that component, thus reducing it's ability to absorb that crash energy.

If I understand you correctly, although dings and dents might be aesthetically unpleasant, it's important to get them repaired anyway, because some of the part's energy absorbing (crushing) ability has been removed from the part, thus compromising its ability to absorb energy through crushing in subsequent collisions.

I thought it takes 5 teaspoons of sperms to power a car...*facepalm*

I love watching your videos and while working on my driving school, this video showed up and made my class so much better! Keep up the amazing content ❤❤❤

Now you know how a Mercedes bends

Fantastic stuff Henry. I'll show this to my classes after Christmas when we're preparing for exams!

I think this is one of the most informative videos I've watched here,I had no idea that the front of the car does that. New appreciation to it.

A new car built by my company leaves somewhere traveling at 60 mph. The rear differential locks up. The car crashes and burns with everyone trapped inside. Now, should we initiate a recall? Take the number of vehicles in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one.

Do you know what I like more than crashing cars....? KNOWLEDGE

Ah very informative. It is astonishing to know what level of engineering and Physics goes into making cars and other machines of our daily lives. Thanks for such a nice video.

You should have added the purpose of airbags, which are also designed to decelerate your body vs the car. What is often mistakenly assumed is that airbags are soft cushions that hit your face, but if that were the case, they would shred apart from the explosion and your face would be hit by a huge amount of shrapnel from the airbag's micro-explosion. Instead, airbags are actually made of a material that is similar to a basketball so that they could withstand the pressure of the sudden inflation, and when they hit you in the face, it really feels like a basketball thrown right into your nose.

Oh, thanks for uploading this 4 days before my driving test. :D

When I asked a friend of mine, who is a firefighter, abour car crashes, he told me about an observation he did. More accidents with low speed cars (like 30-40 km/h) were fatal for the driver in relation to accidents with arround double the speed. Our explanation was that the engineblock gets crushed at arround 70 km/h but is pushed into the driving compartment when on lower speed consequently killing the driver. Needless to say that there is an upper Border of speed to make this work, since there is only so kuch energy the engineblock can take until it is completly crushed.

This helped dispel the myth that older cars (being an older guy I remember those old "solid" cars) are safer than the newer, lighter vehicles. Sharing this!

0:29 Funny, I've seen the exact same teaspoons in my biology book.

"Cars are carefully designed to crumple when they crash." I guess the Cybertruck designers missed this part.

a full day is now 22 hours?

Crash? I think you mean rapid unplanned dis-assembly!

...and this video is epitome of why we love physics.

As if I can afFORD a car. Get it? Ok I'll go away....

off topic: can you do an episode on internal combustion engines? I've always wanted to know how they worked

Excellent work as usual, Henry!

Awesome! Thanks Henry and Ford :) ....Henry Ford. :O Omg!

a lot of people actually want to drive a batmobile

I wish he would've talked more about how speed and such affect accidents, and perhaps also make a "Drive Safely" PSA. I think more people would listen to Henry about the dangers of driving than the Secretary of State.

Thanks!! I love your videos ! You can explain so good! I like your concept of drowning by hand the graphics and your funny animations!

Great video, but I also really wanted to learn about head on collisions, like the transfer of energy involved and the different forces during the crash

great video!

Ive tried to explain this to so many old people who lament that cars "plastic" now instead of metal.

From 1:38 - What if the beam/the front part is replaced with Spring/coil? which can be absorbed energy and divert it to ground.

to all those people saying first here, you're wrong! this was on vessel first

I love your videos. Greetings from Germany

I did not know that, I just figured air bags were the only thing keeping us alive in crashes but this is amazing explanation :)

Crashed my car a couple months ago going about 70 km/hr, the car was totaled and I barely got a scratch on my elbow that didn't even leave a mark. Cars are absolutely safer nowdays

0:28 That doesnt look like gas to me...

im going to buy a ford now. goodjob

I need to send my parents this video lol. They still complain that cars nowadays are made out of outsourced garbage because they crumple and the old ones were so strong because they were made of steel. Man steel ain’t gonna absorb any of the impact 😂

If the car's fast enough, can the crumple zone become a death zone? Also, I'll be very pleased if you make one video on Airbags.

2 dislikes and it hasn't even been long enough since the upload for one viewing. xD. Seems like we have some trolls.

Cybertrucks bad? 😮

You're drivin' along, you're drivin' along, the kids start shouting from the back seat, "I gotta go to the bathroom, Daddy!" "Not now, damn it!" Truck tire. AHHHH, I CAN'T STOP!

Awsome video, but you should have also discussed the designed give of a seat belt. And the awesome speeds of the airbags. Ive been in a car crash before, t wasn't fun.

1 liter of gasoline does not weight 1 kilogram, it's something around 0.75 kg, and the energy from 1 liter of gasoline burning is around 32 MJ on average

I guess gta wasn't aware of this

I'm a car modder, but not like scraping the pavement and loud exhaust on a small Japanese car haha. My current project is making a 83 vw to be the most crash resistant. I'm trying to find a blend between avoiding permanent damage to the vehicle and absorbing impact. The read bumper mounts which are normally designed to crush have a large coil spring to help reduce permanent damage while the fronts have a fault zone at a cheap, easy to replace and easy to crush bracket that cost $4 to make/replace per side. My goal is to be able to get in an accident rear ending a car at 20mph then to be rear ended at 20mph and to only have the two front bracket to replace. Of course in testing it out on a large tree and not on the freeway haha

Many people believe that if you crash head to head with another car, both cars having the same speed, is like cashing straight into a wall with double the speed. My driving instructor told me that during my driving lessons and we pretty much argue because I was saying that it doesn't matter if you crash into another car (of the same mass) or into a brick wall. But how do we prove this? I justify this to myself like this: 1) in the first situation, the energy equals the kinetic energy of the 1st car plus the kinetic energy of the second (which is the same, because of the same speed the cars have). Now after the crash the energy has to stay the same as before the crash. So the two cars after the crash actually exchange energy, that is why both cars get crumbled. 2) In the second situation, the energy equals only to the kinetic energy of the car (as the wall doesn't move => no kinetic energy). So, just like the first situation, the energy has to be the same before and after the crash. when the car crashes into the wall and provided the wall doesn't get destroyed, the energy gets mirrored back to the car. If the car crashes into the wall with double the speed the energy that is returned to it would be 4 times more, so the damage to the car would be way even bigger.

I am a Stegassaurus

BeamNG.drive!!!

"Meticulously Engineered Destruction" sounds like an awesome metal song.

Nicely done. I didn't know that this was an advert. until the end! Loved it!

0:43 when you cant draw an elephant but are a big fan of dinosaurs

Dear Henry, what is a charge? Often we talk about subatomic particles having a positive or a negative charge (or no charge at all). But what exactly IS a charge and what's the difference between positive, negative, and neutral particles.

Since you were talking about organ difsormations, and wounds, maybe you could try to make a serie of videos about imaging techniques, as these imply a lots of physics, and most people barely understand the whereabouts of MRI (uh, you go in a big magnet and boom, pictures), PET-scan (with a dog? a cat?), and other techniques. It could give people more insight about the pro's and con's of each technique, and maybe allow them to have an idea of what they undergo when they go to the hospital. (maybe even for medical doctors. I once had an inspector of health security coming to a lab, asking to put a radioactive label near some stocks of D2O, 13C-glucose, 15N, 18O and so on)

i definetely support this channel and you . I like your videos

is no one going to talk about how cool a sponsored video this is

Should have featured a Model S crash pic, it's super cool.

HAHA funny how the thumbnail is a car running into a tree and talking about car Physics like paul walking hitting a tree he's the expert :') #WATCHOUTFORTHATTREE!

This is pretty much my favorite channel

I'm a Quality Engineer in the electronics industry. Trust me. Sudden stops are no better for robots than they are for humans, particularly since the advent of lead free solders. Ever wonder why your iPhone breaks when you drop it on the side walk? Same concept.

Finally! Been waiting for a video for so long!

You can do an experiment like this with matchstick boxes. Drop a matchstick box on the slidy end Then open the box a bit and drop it again and notice the change

Those early cars also lacked seatbelts, which were forced on Fords by Robert MacNamara, who had observed their value during ww2, but he still screwed up the Vietnam war

DO The Physics of Skyding : like the energy from the speed of free fall and deceleration from the parachute opening and maybe more. that would be awsome !

I just wanted to say good job on the video even if it is sponsored and sponsored content I think it was good thank you very much

Wow, the stuff I didn't know. This is cool, and thank you for making it easy to understand.

Hey, can you do a video about treadmill running vs outdoor running? This debate with my friend will not end.

LOL Just picked up my Ford today from the body shop after being rear ended about a month ago. Not much in the rear to absorb the energy on my little Ford Focus hatchback.

I like the music! Great job, as always!

I will recommend a video idea:The Bloop Mystery

Dear +MinutePhysics, any chance you could make an episode on Lagiewka Bumper?

while i know this was uploaded to Vessel first.i do find it rather ironic since it is snowing like crazy in northern Utah, and i'm sure there will be plenty of accidents.

Finally a good old hand drawn video :D

It would be cool if you added this: How fast the car needs to be to a wheel come out when it crashes? Or a version about motorcycles. Or, Physics of Plane Crashes, and other things related to vehicles. I think i should commented in newer videos

You know, I feel so smart when watching your videos and pretending that I understand what you are talking about

this boutta be the best physics assignment my teachers ever seen

Steel rails connected to the front bumper? Not in any modern car I've seen, unless he is referring to the bent sheet metal structure on either side of the engine compartment as a "rail"

At 0:28 I thought we went from physics to biology when you drew 5 spermatozoa, until I realised they were teaspoons.

Seatbelts also function to lengthen the time in takes you to become stationary. In addition to making sure you don't go flying out of the car!

20 milliseconds into the crash: Speed of your front bumper 0 kph Speed of your rear bumper 60 kph. Have fun.

You do the, relatively, simple physics lesson of elastic vs. inelastic collisions, if you haven't already. Also, if you don't feel it's below your pay-grade to do so.

what about military vehicles, like tanks travel at a high speed as well or those offroad vehicles where they do tricks like flying and jumping....just curious

please tell us also , all the physics behind car crashing that they told you!!

i am a crash investigator. that was an awesome video. just like all of them. YEA science

This was really cool. I love these videos.

These videos are the only ones where auto-generated captions work correctly

If you were wrapped in some kind of hard body casing would it keep your organs in place so you could survive very high G forces? I don't know a lot about this stuff. I heard a story once that a man fell from an airplane and his chute didn't open so he fell horizontally or flat and he survived because his organs didn't move very far, wheras if he had landed on his feet the organs could have separated and moved around easily.

The influence of seat belts should have been mentioned. Firstly because without it, the cars decelerate in a progressive way but not the body of the driver if it is not firmly attached to the car! Secondly, the acceleration (retardation) of a 56 km/h crash (standard speed of many regulation crash tests) in 50 cm crumple gives you around 25g which is pretty higher what fighter pilot may experience (9g). However add to that the controlled elongation of seat belts and you obtain a total ride down distance necessary to reduce the acceleration to around 15g, pretty close if what experienced by fighter pilot as correctly claimed by the video.

How would having the car seat facing backwards alter the effects of the crash on the human body? I've often read that rear facing seats are safer for passengers, but there's never the numbers that you attach to your videos.

Speed has never killed anyone. Suddenly getting stationary, that's what get you.

The effect of a car's engine is only 20% during optimal conditions, straight road, constant speed etc. A normal person would be lucky to press the engine's effect to 10% due to accelarating, breaking and standing still. This has nothing to do with the video, but felt like posting it anyway.