It’s hot in China right now. It’s summer, after all, so that’s to be expected. This year, though, the heat has spawned a viral video showing “pregnant cars” with huge round bubbles on their hoods and doors.
The implication is that a Chinese heatwave has been so extreme that it caused vinyl wraps to balloon up to this immense degree. There’s a certain intuitive nature to this. Heat makes things expand, air included. Thus, extreme temperatures could make vinyl wraps balloon out like a big pregnant belly, right?
![Vidframe Min Top](https://images-stag.jazelc.com/uploads/theautopian-m2en/vidframe_min_top1.png)
![Vidframe Min Bottom](https://images-stag.jazelc.com/uploads/theautopian-m2en/vidframe_min_bottom1.png)
Many outlets fell for this, including The Times of India and The Express Tribune. But a casual examination suggests the whole heatwave explanation is pretty nonsense. Let’s watch the video, do a little science, and talk about what’s really going on here.
Protective films on vehicles inflated in heat wave in China
pic.twitter.com/jcCu3v9gk1— Science girl (@gunsnrosesgirl3) August 10, 2024
Examine The Evidence
The video has been shared and reshared on Twitter many times. A version was posted by reporter Jennifer Zeng on August 6, while a clearer version was shared by Pritam on August 9. When reposted by Science Girl, this misleading video gained over 9 million views.
Each car has these huge ballooning bubbles in its vinyl wrap, filled with many gallons of air. Roughly translated, the Chinese audio comments on how the vinyl has puffed up. The narrator says “This is not too bad, you can still see directly ahead,” referring to one of the hood bulges. The audio doesn’t tell us much about what’s going on, but the Chinese text tells us that this was apparently taken in Hubei province on June 5.
![Vlcsnap 00059](https://images-stag.jazelc.com/uploads/theautopian-m2en/vlcsnap-00059-e1723448541328.png)
The prevailing theory from posters and the press is that a Chinese summer heatwave caused this problem. But that seems entirely unlikely if you run the numbers. Science time!
It’s true that small air bubbles in vinyl wraps are not unusual. Properly applying the film involves removing the air bubbles for a clean look, but it’s plausible that a hasty or lazy installer may have left some air bubbles behind. However, the idea that leaving these vehicles out on a hot day could create these huge bulging bubbles? That’s difficult to believe. Here’s some math to explain why.
Imagine that a whole quart (~0.94 L) of air was trapped underneath the vinyl wrap on the hood of one of these vehicles. That would be a sizeable bulge that you could never miss on sight. Nobody would accept a wrap with a bubble that big, but let’s be generous in our calculations. Imagine that air bubble was there when the vinyl was installed at a temperature of 68 F (20 C). If you then took that car outside on a hot day of 104 F (40 C), the air would expand. By how much? Only a disappointing 7%! Your quart-sized bubble would now be 1.068 quarts (1.004 L) in volume assuming the same atmospheric pressure.
Meanwhile, the bubbles we’re seeing are many gallons in size. That doesn’t check out. Basically, there’s no way heat alone could have caused these bulges. Air simply doesn’t expand enough to generate such extreme results.
![Vlcsnap 00061](https://images-stag.jazelc.com/uploads/theautopian-m2en/vlcsnap-00061-e1723448615223.png)
Another theory put forth was that outgassing from the vinyl or adhesive caused this phenomenon. It is conceivable that breakdown under heat could release some gases from the vinyl, it’s true. However, it’s simply not plausible that a thin layer of vinyl could release so many gallons of gas—let alone while retaining its structural integrity and remaining visibly unaffected in any other way!
If you think critically and do the research, you’ll realize there has to be another explanation. Especially given that on June 5, the temperature in Hubei was only 79 F. Even as temperatures have risen closer to 100 F in recent days, that’s still not hot enough to explain anything. After all, Texas regularly hits those kinds of temperatures. There are plenty of wrapped cars there that survive without issue!
There is one thing, however, that generates bubbles in vinyl wraps exactly like these ones. Compressed air! In fact, blowing air under a vinyl wrap is a pretty common way to remove it. The typical technique involves inserting a compressed air nozzle under the corner of the wrap and inflating it to lift the wrap up from the hood. Head over to one of the many discussions on Reddit, and you’ll find a bunch of commenters from the vinyl industry saying just that.
So what’s the deal with this video? Well, I can think of two explanations. Somebody potentially saw these cars in the process of having their wraps removed, and simply assumed it was down to the warm local temperatures. Alternatively, it was a joke video put together that has been misinterpreted across a significant language barrier.
Out of extreme caution, I’ll say there’s an extremely tiny chance that there was some terrible batch of Chinese vinyl that maybe outgassed to some insane degree. But it’s hard to see how that would be the case. Especially given that most of the cars shown only show bubbling on one or two panels. You’d expect the vinyl to be bubbling all over if it was a heat-related outgassing issue.
![Vlcsnap 00060](https://images-stag.jazelc.com/uploads/theautopian-m2en/vlcsnap-00060-e1723448659697.png)
It’s a shame that so many Twitter accounts—and news outlets—uncritically ran with this story about heatwaves and pregnant vinyl-wrapped cars. A bit of thinking and checking the weather forecast would have revealed all was not as it seemed! Of course, many newsrooms don’t employ engineers or scientists on their regular payroll, but it’s still important to examine exceptional claims like these before printing.
Ultimately, critical analysis and a bit of good old science will help you find the truth, even if Twitter is wrong. My engineering degree has never found me fame or fortune, but it’s given me the key skills to see through things like this!
Image credits: Pritam via Twitter screenshot
maybe forced air coming into a crease in the gaping maw near the edge of the audi grill???
They’re just trying to copy the bloated cars of America
Also figure these are just for clickbait and are made on Photoshop…or a prank as mentioned
I smell another Takata air bag recall.
Audi drivers full of hot air.
Oh. My. God, Becky…
As a chemist, my brain immediately went to PV=nRT. I used that equation so many times in phys. chem. class
DIY Citroen Cactus…
With four of the five top stories, it appears today is
Lewin Day.
You know the day destroys the night
Night divides the day
Tried to run, tried to hide
Break on through to the other side
Between the embedded videos, background ads, and pop-downs, this site has now reached Jalopnik-levels of glitchiness. The page crashed and reloaded 3x just trying to serve up this article.
I’m not having these issues, and I’m using stock MS Edge. Do you see this happening in other websites as well? It could be due to malware, happens to the best of us 🙂
Thanks for assuming I’m “the best of us.” ????.
Safari on iPhone.
I work in tech, and I know we’re all just a click away from really nasty stuff on the web.
That being said, I have only Android and Windows, so I can’t tell how the site would load on a setup similar to yours 🙂
I can confirm on my Android tablet with Chrome that it regularly freezes up when scrolling over ads. My iPhone doesn’t freeze up but it does start to jump around on all over the page with the roll over ads as they expand and contract. Makes it very frustrating to view on mobile.
Same, moz on win and android, safari on ios and brave on win. The ad popups cause the glitches.
I emailed Hardigree about it two months ago but haven’t seen any real change. He acknowledged I had a concern at least.
I suspect becoming a member will cause the adverts to go away. Could be wrong, but they gotta pull the dosh somehow.
I am a member and logged in on all my devices. The ads still exist.
Good to know. Must be some weirdness in the ad delivery system. I get random ads, huge screen dominators, and ads that just keep coming back. Brave usually blocks ads quite well, but can’t seem to handle the ones on autopian. It does get annoying at times, but the content is worth it and the commenters aren’t the usual internet aholes.
Hood Hooters™
Would a car bra help?
This is nothing more than a cosmic retribution for all the idiots who have hung truck nuts off the rear view mirror rather than the rear bumper like God intended.
Move along people. Nothing to see here. /s
Arnold: “It’s not a tumor.”
Sensational Internet Post May Not Be True!
Maybe I shouldn’t get my medical advice from Reddit, my life coaching from Instagram, and my political advice from TikTok? Well I’m sure glad Autopian is still around as a rock-solid go-to information source.
You go, Lewin! Call out these lazy and unprofessional media accounts!
The only plausible explanation I could think of was that maybe the vinyl or adhesive used was somehow hygroscopic, and absorbed great amounts of moisture due to the moisture, which is a major exacerbating element of a heat wave. Water multiplies in volume by 1,646 when it evaporates, so the bubbles would be physically possible, the presence of a hot engine below would explain the hood-only bulge on the white cars and the darker car also makes sense as it would absorb more sunlight and heat up all the panels.
That said, unless this can be tested, I’m inclined to believe it was a deliberate joke or even a new form of vandalism. I can imagine some kids walking around with CO2 cannisters and a simple nozzle and just popping up someone’s PPF for fun. Nothing like some good, old-fashioned prankless harm.
I think water is the likeliest explanation. There’s a bit of a trend of writing off things that are silly or unlikely as fake/staged/done for YouTube, and while those things do happen, that “faked for views” logic falls apart pretty quickly; YouTube doesn’t remotely pay out that well.
Leave a lot of water under there, heat up the water into vapor, boom, there’s your ruined wrap.
If it were vaporized water wouldn’t it just immediately condense from the pressure caused by the expanding vinyl?
Not if the vinyl is soft and flexible enough (elastic). The vapor could build enough pressure to hold soft vinyl that’s getting even weaker up as it goes through plastic deformation (the shape of the vinyl is permanently changed, which also then does not require net new force to be in that shape – like blowing up a balloon, except it won’t go back into shape when deflated). It wouldn’t confirm that it was water vapor per se, but seeing some after pictures would be nice – it probably looks like a sad deflated sac. The presence of water underneath that would be a much stronger clue, of course.
It’s pretty easy to see this work even in your kitchen. Stretch plastic wrap over a bowl of hot water. The plastic wrap will expand up and away from the bowl. Put it in the fridge, wait a bit, and the plastic wrap will be saggy and have droplets on the bottom.
Otherwise, like Lewin points out, it’s so much air it’d mean someone is walking around with air tanks or a giant compressor and surreptitiously pumping gallons of air under peoples’ wraps.
While I definitely agree, and it’s more fun to believe and try to find a real explanation, this is a pretty much free thing to do if you’re in it for the views. Wraps need to be removed periodically and compressed air is very cheap. Then take into account the value and purchasing power of the Yuan, and a few USD from YouTube plus selling footage to news agencies is well worth it (plus the attention/fun factor, of course. Never underestimate what people are willing to do just for kicks).
That said, I want the water build-up explanation to be true, I just think it’s more likely to be deliberate, whether it’s a views-farm, prank or vandalism.
Except that “wet” application, using soapy water and a tiny bit of glycerine, has been around for decades. Wet the surface, position the vinyl, squeegee the water out. You generally get fewer bubbles with this method, not more. If it bubbled up in the heat, no one would do it this way.
The prank/joke explanation seems most likely. The adhesive may be failing here and there due to the heat (heat is also used to remove vinyl and wraps), and someone sees a loose edge and has an idea.
Wet application works great, especially with quality vinyl. That’s why I was wondering if maybe this is a cheaper composite with a hygroscopic adhesive that absorbs and retains water. If any market is going to adopt a cheaper, non-vinyl plastic wrap without much testing, it’s China. I’m just trying to keep the magic alive a little bit, it’s still far more likely to be deliberate.
A French pole vault athlete had a similar issue…
He may have lost at the Olympics, but he absolutely won at getting to spend the rest of his life talking about how his giant dick cost him a medal.
Some have predicted a post sports career in the porn industry?
He actually did get a porn offer for $250K (not that he took it) Hilarious!
I think people are more motivated to believe chinese wrap applicators (?) are bad at their jobs when they share this, because some of these look very “beautiful cabin crew scarlett johansson”.
I’m pretty certain the hood gets hotter than 100 degrees after the car has been running a while anyways (and that the hood reaches about the same temp in 70 degree as 100 degree weather).
Many vehicles have heat shield attached to the hood underneath.
I used to work in a factory that makes them.
The hood still gets hot.
Can confirm that the hood gets heat from the engine bay. In the winter when there is ice on my car the stuff on the hood melts first once you start it.
Perhaps – but you’re still not getting maybe more than 30% expansion. And keep in mind my premise of starting with a 1 quart air bubble is ridiculous in itself.
Agreed, I’m not disputing anything you said, merely adding another reason why the proposed idea is ridiculous.
Way to burst our bubble.
I think they’re likely fake but if they weren’t could it be vaporized water from a recent installation?
Perhaps, but I doubt it. Because you’d see it on more than just one panel.