Happy National Puzzle Day! I was a little hot and cold on today's puzzle (lol sorry), but I hope you enjoy all of my experimentation anyway 😅 Also, yesterday was the St Paul Winter Carnival Puzzle Competition, so stay tuned for a video all about that in two weeks!

Ooooohhh science question, YAY: so, color change technology works works by altering the crystalline structure of the paint/dye. Think of it simplistically as when it's cold the crystals are all leaning one way and when you heat them up they roll over in a sense. As the paint/dye ages the crystals get more and more sluggish to roll over, as it were. Your hands probably could've turned the puzzle when it was brand new. And to answer your questions, yes, they' could've had a simplistic design. They probably didn't because then it would have been easily solvable. My biggest gripe with this particular is actually the piece quality. They knew people would be moving these pieces around a LOT. They should've increased the piece stability accordingly. Well, I hope that answered your questions a little bit! Glad you stuck it out. Can't wait for the Ice show episode! I left Minneapolis around 15 years ago, and while I don't miss the cold I do miss the Ice show sometimes.

You're probably the only person to ever finish this puzzle. Most people would have given up. I know I would have! I don't have a hair dryer!

Dude, I would not have put up with that puzzle. At one point, I thought that you were going to declare it not worth it, but half of the video was still left, so I knew that you figured out something. Not only the hair dryer, but another tool that I won’t spoil for those that haven’t finished the video yet. This puzzle was certainly a test in perseverance!

That slowmo of the puzzles turning hot pink is actually satisfying. Also I love how clever Karen can be outside of puzzles and games. The frozen vegetable bag, heating bag/pad and hair dryer plus diffuser are smart solutions. Crazy that all those items mentioned were used for a puzzle lmao

The hair dryer and lightbox was such a great idea. If you didn't need 5 hours and a lightbox to solve it then you could've done the puzzle in a sauna! Then you'd be able to write off a spa day as a video expense lol!

Whoa. 😳 Thanks for taking one for the team. It’s safe to say I shan’t be purchasing this puzzle to solve. I don’t have a diffuser for my HAIRDRYER, so I’d be chasing pieces all over the place. 😂 I wonder how well a heating pad/throw/blanket would have worked under your foam board? Great video, as always!

I'm guessing they used leuco dyes instead of liquid crystals, because that would allow them to create the gradient; they consist of molecules that switch between colorless (the hot state) and opaque (the cold state), which are made into microcapsules with the necessary reactants to facilitate the molecular state change. Essentially, with the right temperature and the right stuff around it, the molecule changes shape and either becomes opaque in a specific color (depending on the molecule) or transparent. Because the microcapsules are much larger than ordinary dye particles, there are some challenges to both durability and manufacturing, depending on the form factor, which is a somewhat technical way to say that putting it on paper makes it not last as long.

My guess is that when the puzzle is very fresh your body heat would actually work, but the longer it's been sitting, the more heat you need to activate it. The reason I'm guessing this is actually because when I was in elementary school, after we had the whole fire safety talk, they would give out heat activated color changing pencils, that actually did work with your hand, and I would guess this puzzle uses a similar technology.

Karen's videos are so well produced, you can tell she puts a lot of hours into them. 😁👌🏻

I'm sure you're the only one who approached this puzzle with such dedication 😁 It's obvious that this puzzle was produced with this color-changing gimmick in mind as the most important aspect, not the actual solvability.

We need a “what Karen has said about jigsaw puzzles out of context” video 😂😂😂

A marriage proposal through a jigsaw puzzle, that’s so cute!!!

There is no way I would have been able to stick this out! The number of things it needs is mind boggling. I loved how you used so many different ideas to get through the puzzle.

I definitely wouldn't have finished that! Maybe it would have been doable when it was brand new, but still. I think a much more fun idea would be to have a puzzle with very unique, fun piece shapes that you could solve as a solid-color puzzle. Then when you're done, you could reveal the "secret image" with a hair dryer (this is assuming you could make an image more interesting than a gradient). The bonus to this approach is that you'd be able to use an ordinary hair dryer without the diffusion attachment (who has one of those?) and not worry about the pieces blowing away, because they'd all be attached together at that point!

I'd like to see this concept well executed. If it was cut well it would have been a better puzzle.

Great choice of music, Karen. I'm sure it made people all over the world stand and applaud when the last piece was put in. Thanks for the adventure in this nearby galaxy.

The patience! The tenacity! The sheer resourcefulness on display with this monster! I truly can't believe you finished this -- not because I doubt your ability (We've all seen you solve some truly hardcore jigsaw puzzles) -- but because you would have been so justified in bailing. I feel like even having something as simple as a more unique piece cut would have saved this one! Like, at least in that case you wouldn't have needed the literal lightbox. Totally commendable solve for a puzzle that truly didn't deserve you!

Imagine someone to open your freezer to find a puzzle inside xD

This puzzle would - with or without the noises of my hairdryer - absolutely drive me nuts 😂 You're great!!

60 pieces an hour or 1 piece a minute and a hairdryer and light pad and the fact you got it done-made this video so much fun! I hope you kept it together and thanks for sharing this one as I know I could never get it done as quickly if at all.

As soon as I saw the pieces I had Ketchup puzzle flashbacks! I absolutely would not have finished that puzzle. It was fun to see the colors change with your magic hair dryer. Well done.

This puzzle almost made me mad... until I saw your video ! THANK YOU SO MUCH KAREN ! About 100 pieces were connected and I was blocked when I searched for help. I hair-dried my work and... discovered so many errors. Heat was the key-tip. Did you notice, at last, the shapes on the box (recto&verso) are the actual ones ? Start from the left (the "pink" corners). And drop the 3 columns on the right (côté "orange"): they don't exist, it'a trap. Greetings from France. (By the way, I suscribed your channel) Ce puzzle m'a presque rendu fou... jusqu'à ce que je voie ta vidéo ! MERCI BEAUCOUP KAREN ! Environ 100 pièces étaient connectées et j'étais bloqué lorsque j'ai cherché de l'aide sur Internet. J'ai passé mon travail au sèche-cheveux et... j'ai découvert plein d'erreurs. La chaleur était la clé. As-tu remarqué, à la fin, que les formes sur la boîte (recto&verso) sont les bonnes ? Commencez par la gauche (les coins "roses"). Et laissez tomber les 3 colonnes de droite (côté "orange") : elles n'existent pas, c'est un piège. Salutations de France. (Au passage, je me suis abonné à votre chaîne)

You deserve a trophy for solving that one! 👏

Your perseverance on this puzzle is genuinely inspiring

The sponsor reminds me of how Joey Richter from starkid proposed to Lauren by doing a huge puzzle with her of the two of them and their dog and at the end (weeks of work I think since it was a black and white puzzle) he revealed the hidden pieces of the dog holding a wedding ring

I was a fan of your videos, Karen, from way back when in the Nerdfighter and crafting days, and I don't know you but it still makes me really happy to see you finding so much success and joy with your puzzle videos. It warms my heart like a hair dryer!😊

You are my hero! Such a legend for sticking with this, and that grotty experience of working through those horrible pieces will help you out with better made puzzles :-) I would have given up 1/3rd of the way through, hairdryer or no hairdryer

I have no idea why youtube recommended this to me, or why I actually watched the whole thing start to finish, but i can say with confidence that this is the nerdiest video I have ever watched.

My mom loves watching you, and we love jigsaw puzzles! Keep up the great work Karen!

I found your channel last year and I've been hooked ever since. To the point that you actually got me back into jigsaw puzzles! I don't think I could've stuck this puzzle out so you're braver than I am. Also this was just what I needed today, so thank you for the laugh. Happy National Puzzle Day right back at you, Karen!

i feel like a yellow to purple gradient (or just a wider one in general) would have made this a lot easier. also adding the patterns would make near-duplicate pieces less of an issue

You have made so many puzzlers happy. Knowing that they are not the only ones struggling to do puzzles. Doing this for us was great. I for one feel that I really don’t have to feel bad about having a hard time. I’m glad you took the time to do this woohoo❤❤

Happy National Puzzle Day Karen!!! 🥳 I'm glad you did this one and not me, because I don't even have a hairdryer to solve it! False fits are definitely the most frustrating kind of puzzle, it could definitely be possible to produce a more complex puzzle with this color-changing material, but it would not be easy or cheap to make, so it definitely feels like they cut a few corners here.

Your music choice when you used the diffuser is cracking me up!! I love it!! Still watching to see you solve it 😊

"When millions of Americans yell at their TVs for their favorite football teams, you are..." "...yelling at a woman to put a curl diffuser on her hairdryer to use in her jigsaw puzzle." And actuall conversation I just had with my husband this morning while watching this video 😂😂😂

I am so impressed by the perseverance and ingenuity it took for you to solve this puzzle!! And your comments about the design seem spot on. Well done!! 😀

You have way more determination than I do because I would not have finished it. I also wouldn't have blamed you a bit for giving up. I loved watching they hairdryer change the finished puzzle. The images you produced were awesome. I want to screenshot one image for a wallpaper. Stay warm up in St. Paul!

Dude I wish I had you’re patience. It takes me forever to do normal puzzles with plenty of different colors and textures to look at. Props to you for finishing the puzzle. Hair dryer

I‘m so happy that you finished it… because the footage at the end is really beautiful. With changing the colour differently and great music in the background. So well done how you presented the solved puzzle 👍

This was hysterical! Had so much fun watching you do this puzzle! Extra, extra kudos for figuring out the best heat source for the best results! Love your channel!

Also your editing is always really great but this video especially stood out to me. The more vlog-esque style at the beginning and all of the slow-mo with dramatic music was all great!

I was amazed at all the hurdles you overcame to solve this puzzle. Great video and wonderful editing. I was surprised at the hair dryer as a solution but I guess a heat gun would have been too hot and also lacking a diffuser, which ultimately was the game changer. The color change was fun to watch, so thanks for going through all that!

To be fair, I don't know what color-changing stuff they're using, but some of them do start to expire incredibly quickly, so that might be a reason for why the box says body heat is enough but you're having to use a hair dryer. When it was brand new, it might've worked as advertised. Most color-changing stuff you find easily are made of tiny crystals, but that would probably make cutting the puzzle difficult as you can't reliably use laser-cutting (because it might reflect on the crystals into areas it's not supposed to be) and you can't reliably use saw-cutting (because it might split a crystal and thus cause the edges of the pieces to not be smooth.) If that's the case, the technology they used will likely be nowhere near as good as most stuff you see, as it'll have less colors, less sensitivity, and it might expire faster.

The music and editing was great! In this video glad you finally got it done

I'm so glad you figured out the diffuser trick for your hair dryer! I was sending telepathic thoughts about the diffuser while watching the video 😂 I'm the type that needs to see things to completion. I suffered through a foil puzzle by spinmasters because I just had to finish it. The foil has a color shifting aspect which is tough. Congrats on sticking with it!

I am so entertained by you Karen. I laughed my way though this one, and was so proud of you when you thought of the final tool you used! Keep up the great work!

I would never have finished it! 😂 First of all, I don't have a diffuser for my hairdryer, and I have NO patience for false fits. Like, I'm not an expert at puzzling, and I very often make 2 pieces fit that have no business being in each other's businesses, haha! It was satisfying to see the final reveal gradient, though! Thank you for making it so we don't have to do it ourselves! 🤭

This is pure dedication and I am definitely here for it! Awesome video!

Amazing puzzle as always Karen I love watching your videos and that such cool puzzle :)

I didn't believe you solved this puzzle! What courage and patience you have and what a beautiful hairdryer! Lol!

Seeing all the shots of the "spacey landscapes" you could create by adding less or more heat, definitely worth the 5 hours of work!! Such a unique puzzle, truly amazing. I wouldn't wanna put it together myself, I don't even own a diffuser nor a light box!

I think it probably would have warmed up with body heat when you initially got it. I think the color changing effect weakened enough that you needed drastic temperature shifts to see an outcome and not just body temperature.

Proud of you for not giving up! You’ll definitely grout from this experience.

Hate the puzzle, love the music! Great entertaining video! I don’t have a diffuser with my hair dryer, and would never attempt such a frustrating thing. But, I’m glad you did and gave us a fun video - I especially liked the hand shadow.

Just watching this was giving me flashbacks of watching you do the Heinz puzzle. Another thanks for doing it so us much less patient puzzlers could save their sanity.

Woah. You were so creative and had so much perseverance 💪👏 Using the tools around you - like the hot water bottle, peas, hair dryer + diffuser, and lightbox - was so clever

Oh my goodness! So much work! You are very clever for coming up with all of these strategies! The hairdryer footage was very satisfying. 😊

So I probably would not have finished this myself (not least of which because I don't have a hair dryer with a diffuser), but I'm so glad you did! Those color change shots look amazing, especially on the time lapse! It's a really cool and unique thing to get to see. :) Thanks for putting up with it!

You're so right, I would have given up so fast lol Loved the extended dramatic color changing scenes btw, made the puzzle much cooler!

Oh my! Bless your heart. You have more patience than I could ever hope to have. Congratulations! Your idea of using a hairdryer was epic.

great job powering through this one. excellent use of tools. especially the diffuser on the hairdryer!

That B-Roll looks great :] Glad you had the fortitude and good ideas to carry on to the end! Especially that you had the diffuser for the Hair Dryer -- and the light box was definitely inspired.

You're so smart 😁. I love seeing you come up with all these ideas to overcome challenges.

Always new and funky puzzle ideas. Looks fun

Happy national puzzle day…wow, and it’s my birthday. Karen, I have fallen in love with your channel. I’ve purchased about a dozen now, many of which you have done and I loved them, and my husband bought me a puzzle table for Christmas, so you are having an influence on us.

You’re dedication to finish this is outstanding! 🎉

Karen, the pigment molecules at room temp or colder are at their most stable shape, which reflects the deep blue to purple colors. When these molecules absorb heat energy, their most stable shape changes, and reflects blue or pink. As they cool off, they lose energy and return to their original shape/orientation, which reflects that darker color. Printing on top of the pigment would only affect the color changing molecules underneath the printing, so it is possible.

I would’ve quit that puzzle so fast but I’m happy to have seen what it looks like when solved! Your dedication is impressive!

The Areaware gradient puzzle is one of the few I have decided not to finish (I didn't try a light box), so... I probably would have absolutely hated this puzzle. I'm so glad that Karen did it so I don't have to!

I love all the triumphant music 😂 great job!! I definitely would have given up!

You truly are braver than any marine to finish this puzzle. This was so much fun to watch!

"I'm now going to put my puzzle in the freezer" sounds like a regular Duolingo sentence 😂

Of course we always watch the whole video. Sometimes multiple times. Loved it. Love you

Great job! If anyone could finish this puzzle, you could ... glad you stuck with it! I don't think I would have stuck with it (even if I had a diffuser and light box!)

I stumbled upon your channel a couple of weeks ago, and I've got to tell you that you are so much fun to watch, and this video is no exception! Keep being you!

I'm glad you stuck it out, those shots at the end were very satisfying :)

Wow you have way more patience than I do. A regular gradient puzzle would drive me nuts, nevermind having to continually heat up poorly fitting pieces! This puzzle just seems like torture. Good for you for finishing it.

I have never watched a video about puzzles with so much excitement and anticipation before.

Amazing that you really pulled this off. I would have thrown this puzzle in the trash bin or even burned it. The idea behind the puzzle as such is really good. The cutting of the pieces seems to make it painstakingly hard to put it together. Congrats, you made it! The heat impressions at the end were really fun to watch.

Fun! You're channel has great variety. I admit I eventually get tired of just watching just watching a time lapse for an hour ;)

So satisfying to watch those pieces change with the hair dryer! My friend reccomended your channel to me after I had to give up on a puzzle I got for myself for new year's. It was mostly black with pictures of butterflies on it. I tried for hours and only managed to fit two pieces together -- even trying to work on the butterflies didn't help me get anywhere. I don't think I would have been able to do this one, so I definitely commend you for your perseverence!

Wow 😯... Kudos to you for sticking with it until you completly solved the puzzle! Congratulations! I could never have done this. And people say I have patience just for solving any puzzle (I mostly think: "it doesn’t have anything to do with patience"), but THIS is patience for solving a puzzle. 🤪 RESPECT!

The dedication is truly amazing

Cannot wait to get your new puzzle and the one that's coming out in spring.

This was such a joy to watch! Loved the editing and music! That hair dryer really came in clutch 👌 😁

Thermochromism is the property of substances to change colour due to a change in temperature. Examples are the strip on a Duracell battery which indicates battery life remaining, a mood ring, colour changing coffee mugs, or the famous 1990s hypercolour t-shirts. I even think my brothers had matchbox hot wheels cars that colour changed. The two common approaches of thermochromism are based on liquid crystals and leuco dyes and for your jigsaw I would guess they used a leuco dye, which can switch between two chemical forms; one of which is colourless. So chances are one of the layers of paper is actually printed with the gradient colours on it so the solved image. And then a layer of leuco dye is onto of it, so when it’s activates by heat it turns colourless revealing the gradient orange pink you see and when it isn’t activate then it remains the original leuco dye colour, thus the purple/blue, as indigo is the most classic use of a leuco dye for papers and clothing. If this is in fact how it’s printed that the bottom layers is in fact a normal paper jigsaw and the colour changing part is the the purple blue layer then yes I’m sure they could have printed some sort of image/line art/pattern on the gradient paper even if was very slight. I think they may have felt that they may have need a thicker layer of leuco dye to hide the pattern underneath thus affecting its thermochromic ability. Also note the fact you had to use a hair drier on something that was suppose to change with body heat shows how much they didn’t trial this jigsaw design before market. As with all colour changing items I had growing up they lost their ability to change colour after a period of time or use or wash and wear or forcing the reaction back and forth. So maybe the layer on the jigsaw is now no longer as sensitive as it once was before they marketed it. I would have finished that puzzle as I’m too stubborn not too. There would have been a bunch of choice words and anger and many attempts to quit. But I would have continued with it. Would hate to know my time though. I will now read the rest of the comments for any more info on this thermochromic ability

Even though you nearly gave up, you stuck through with it and managed to finish it! It looks so pretty when it’s complete, and it has such a cool concept

So much determination! But the end result was so satisfying!

Man, I am so impressed by your patience. I'm not an expert puzzler though I have completed 5000, 6000, and 7500 piece puzzles before. I'm sure i would have thrown this one in the garbage or set it on fire out of pure frustration.....And then maybe thrown a rock through the window of the company that invented it.

I get so much enjoyment watching you tackle these puzzles. Who'd a thunk it!

So excited to see this!

Heat sensitive colours like that depend a lot on the time of year. I have a colour changing notebook and during the summer when it was getting up to 40C, it got stuck on the warm colour, I had to roll a cold bottle of water over it to get it to change back for a short while. During the winter it's hard to get it to change colour.

U are so cool! It's also satisfying to watch u finish it! ♥️ It's so beautiful

False fits is definitely my most hated puzzle problem to run into. It takes something that could be fun and challenging to just annoying.

Hey. You pushed through it. You should be super proud of yourself!!! Great job.

OMG when you decided to use the diffuser... best moment ever on your channel!!! Lol

I can't believe you had the patience to complete this. Fantastic!

There's a 100 piece clear acrylic puzzle sold at Five Below that I picked up for fun. It has the same issue of a lot of piece options to put together. Would love to see your take on it because I don't think the light box would work since it's already clear.

Great work as always 😊