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Humans of New York went to Europe to see the refugee crisis firsthand. The photos are striking.

They're fleeing violence to an uncertain future.

This 76-year-old Greek baker has a new routine.

Every morning, Dionysis Arvanitakis asks his workers to make an extra 200 pounds of bread and pastries.


Photo by Brandon Stanton/Humans of New York, used with permission.

He then heads down to the port in his home of Kos, a Greek island in the Aegean Sea where an estimated 200,000 refugees have landed this year after fleeing conflicts in Iraq, Syria, and Afghanistan, among other places. He passes out the loaves of bread to hungry migrants — a warm welcome for the often-weary travelers.

This is one of roughly a dozen stories captured by Humans of New York, a photo project that offers a glimpse into a person's life.

The photographer behind the effort, Brandon Stanton, was on the road in Europe, listening to the experiences of refugees and the people who have greeted them.

Here are some of the stories he's heard since launching the 10-day project on Sept. 25:

1. A baker who knows what it's like to be a migrant

So what motivates a person to devote their time, energy, and money to helping newcomers? For Arvanitakis, it's because he knows what it's like to be one.

He moved from Greece to Australia as a teenager and ended up sleeping on the street. His thoughts on the crisis, via Humans of New York:

"My father was a farmer and we had eight siblings. I went to Australia when I was fifteen because my family didn't have enough to eat. I was on a boat for forty days. When I got there, I couldn't find a job, I couldn't speak English, and I had to sleep on the street. I know what it's like. So everyday I drive the van to the port and hand out bread to the refugees. My son is my business partner. He says, 'Baba, please. It's fine to help. But not every day.' But I still go every day because I know what it feels like to have nothing."

2. Feeling grateful for a small gift

This group photographed in Lesbos, another Greek island in the Aegean (also written as Lesvos), appeared to have little to ease their journey to Europe but took comfort in a gift from a priest.

"Everyone here has been very nice to us. When we got to the beach, there were people there who gave us food and a hug. A priest even gave us this carpet to pray on. He told us: 'We have the same God.'"


Photo by Brandon Stanton/Humans of New York, used with permission.

3. A grief-stricken woman who lost her husband

She and her husband boarded a boat jam-packed with people — so overloaded that the luggage had to be thrown overboard. When it began to sink, her husband gave his life jacket to a woman, she said. She was later rescued; he wasn't found.

“My husband and I sold everything we had to afford the journey. We worked 15 hours a day in Turkey until we had enough money to leave. The smuggler put 152 of us on a boat. Once we saw the boat, many of us wanted to go back, but he told us that anyone who turned back would not get a refund. We had no choice. Both the lower compartment and the deck were filled with people. Waves began to come into the boat so the captain told everyone to throw their baggage into the sea. In the ocean we hit a rock, but the captain told us not to worry. Water began to come into the boat, but again he told us not to worry. We were in the lower compartment and it began to fill with water. It was too tight to move. Everyone began to scream. We were the last ones to get out alive. My husband pulled me out of the window. In the ocean, he took off his life jacket and gave it to a woman. We swam for as long as possible. After several hours he told me he that he was too tired to swim and that he was going to float on his back and rest. It was so dark we could not see. The waves were high. I could hear him calling me but he got further and further away. Eventually a boat found me. They never found my husband."


Photo by Brandon Stanton/Humans of New York, used with permission.

4. Families seeking refuge

Before they left home, this mother told her son that nearby explosions were far away. Then tragedy struck.

"They fired rockets from a mountain near our house. They were very loud, and every time he heard them, he'd run into his room and close the door. We'd tell him fake stories. We'd tell him that there was nothing to worry about, and that the rockets were far away and they would never reach us. Then one day after school he was waiting in a line of school buses. And a rocket hit the bus in front of him. Four of his friends were killed."


Photo by Brandon Stanton/Humans of New York, used with permission.

5. A vital effort from volunteers

This family has aided thousands of migrants as they've arrived in Greece, handing out sandwiches, juice, and water. Even their son has noticed how serious the crisis has become.

“In the past four months alone, we've had twelve thousand refugees stop here. We know because we've counted the sandwiches that we've handed out. They show up battered and beaten. We set up this rest area along the road to hand out sandwiches, juice, and water. One night we had one thousand people here. You could see nothing but heads. We're not professionals, just volunteers. The families break our heart the most. They show up with no money, no papers, and no hotels. Sometimes it's raining and they have nothing but cardboard over their heads. They have nothing for their children, and we know how hard it is to raise kids even in standard conditions. Our son hasn't seen very much of us recently. Even when we are together, the phone is always ringing and we are absent in mind. Recently he asked if we could build a big boat and send the refugees somewhere that there is no war."


Photo by Brandon Stanton/Humans of New York, used with permission.

6. A father desperate to provide a better future for his daughter

"She hasn't known many happy moments," he told Stanton. The man recalled a powerful scene as the family boarded a small boat to Greece.

"I wish I could have done more for her. Her life has been nothing but struggle. She hasn't known many happy moments. She never had a chance to taste childhood. When we were getting on the plastic boat, I heard her say something that broke my heart. She saw her mother being crushed by the crowd, and she screamed: 'Please don't kill my mother! Kill me instead!'"


Photo by Brandon Stanton/Humans of New York, used with permission.

7. A traumatized young girl

Stanton approached a young girl and asked to speak to her mother. The request seemed simple enough, but it triggered a look he described as "uncontrollable fear." A life on the run had conditioned her to expect the worst.

"The extent to which refugee children have been conditioned by their environment is heartbreaking. We wanted permission to take this young girl's photograph, so we asked if her mother was nearby. Her eyes filled with the most uncontrollable fear that I've ever seen in a child. 'Why do you want my mother?' she asked. Later, her parents told us how the family had crouched in the woods while soldiers ransacked their house in Syria. More recently they'd been chased through the woods by Turkish police. After we'd spent a few minutes talking with her parents, she returned to being a child and could not stop hugging us, and laughing, and saying 'I love you so much.' But I went to sleep that night remembering the terror on her face when we first asked to speak to her mother."


Photo by Brandon Stanton/Humans of New York, used with permission.

8. A man who wants to see his brother healthy again

After a sniper shot his brother, he thought the injuries would be fatal, the man told Stanton. His brother survived but needs medical attention, something he's hoping to find in Germany.

"A friend called me at work and told me that a sniper had shot my youngest brother. I rushed to the clinic and he was lying there with a bandage on his head. I unwrapped the bandage to help treat the wound with alcohol, and small pieces of brain were stuck to it. The doctor told me: 'Unless you get him to Damascus, he will die.' I panicked. The road to Damascus went straight through Raqqa and was very dangerous. It took ten hours, because we could only take back roads and we had to drive very far out of the way. My brother was in the back seat, and after a very short time he started to vomit bile. Water was pouring from his eyes. I didn't know what to do. I was so scared. I thought for sure he was dying. But somehow I got him to the hospital. He's paralyzed now and his speech is slow. His memory is OK. He can remember old things. He needs an operation in his eye. We used to do everything together, and now he can't do anything. He can only move his hand. I'm trying to get him to Germany because I hear that maybe the doctors there can help him."

Photo by Brandon Stanton/Humans of New York, used with permission.

9. Finding a friend when you need one most

This young man was taken under the wing of a baker in Austria (these bakers have big hearts!) who helped him settle there. He studied German intensely to help obtain legal immigration status in the country.

"After one month, I arrived in Austria. The first day I was there, I walked into a bakery and met a man named Fritz Hummel. He told me that forty years ago he had visited Syria and he'd been treated well. So he gave me clothes, food, everything. He became like a father to me. He took me to the Rotary Club and introduced me to the entire group. He told them my story and asked: 'How can we help him?' I found a church, and they gave me a place to live. Right away I committed myself to learning the language. I practiced German for 17 hours a day. I read children's stories all day long. I watched television. I tried to meet as many Austrians as possible. After seven months, it was time to meet with a judge to determine my status. I could speak so well at this point, that I asked the judge if we could conduct the interview in German. He couldn't believe it. He was so impressed that I'd already learned German, that he interviewed me for only ten minutes. Then he pointed at my Syrian ID card and said: 'Muhammad, you will never need this again. You are now an Austrian!'"


Photo by Brandon Stanton/Humans of New York, used with permission.

Sometimes the political debate over immigration can muffle the human stories.

The scale of the refugee crisis can seem overwhelming. According to The New York Times, six countries — Germany, Austria, Hungary, Sweden, the Netherlands, and Finland — expect 1.3 million asylum applications by the end of the year.

But these stories help us remember that behind each of these numbers is a person, someone willing to risk their life for a better future.

Gen Z; Millennials; technology; cell phones; social media; teens and technology; teens social media

Gen Z is the first generation less cognitively capable than their parents. Denmark has the solution.

Nearly every parent hopes their child will be better off than they are: smarter, more secure, and more well-adjusted. Many parents see this as a stamp of successful parenting, but something has changed for children growing up today. While younger generations are known for their empathy, their cognitive capabilities seem to be lagging behind those of previous generations for the first time in history.

Dr. Jared Cooney Horvath, a teacher turned cognitive neuroscientist who focuses on human learning, appeared before Congress to discuss concerns about cognitive development in children. In his address to the members of Congress, he says, "A sad fact that our generation has to face is this: our kids are less cognitively capable than we were at their age. Since we've been standardizing and measuring cognitive development since the late 1800s, every generation has outperformed their parents, and that's exactly what we want. We want sharper kids."


kids, intelligence, sharp kids, generations, education, cognitive abilities Student smiling in a classroom, working on a laptop.Photo credit: Canva

Horvath explains that the reason this happens is that each generation has gone to school longer than the previous generation. Gen Z is no exception to the longer duration of time spent in school, but they're the first ones who aren't meeting this normal increase in cognitive development. According to the cognitive neuroscientist, the decline is due to the introduction of screens in the classroom, which started around 2010.

"Across 80 countries, as Jean was just saying, if you look at the data, once countries adopt digital technology widely in schools, performance goes down significantly. To the point where kids who use computers about five hours per day in school for learning purposes will score over two-thirds of a standard deviation less than kids who rarely or never touch tech at school," Horvath reveals.

In most cases, the decline in performance doesn't result in better strategies. The neuroscientist shares that the standardized testing has been adjusted to accommodate lower expectations and shorter attention spans. This is an approach that educators, scientists, and researchers went to Capitol Hill to express wasn't working. But not every country is taking the approach of lowering standards to meet lowered cognitive ability. Denmark went in the opposite direction when it realized their students were slipping behind.

France24 recently interviewed educators in Denmark following their seemingly novel approach to students struggling with cognitive development. Since the beginning of the 2025/2026 school year, Denmark has not only been having students turn in their cellphones, but they've also taken tablets, laptops, and computers out of the classroom. No more digital learning for the majority of the school day. Danes went old school by bringing back physical textbooks, workbooks, and writing assignments. The results have been undeniable. Even the students can't seem to deny the success of the countrywide shift in educational approach.

"I think the biggest issue has been that, because we kind of got rid of the books and started using screens instead, that we've noticed that a lot of the kids have trouble concentrating, so it's pretty easy to swipe with three fingers over to a different screen and have a video game going, for example, in class," Copenhagen English teacher, Islam Dijab tells France24.

Now, instead of computers being part of every lesson, Denmark uses computers very sparingly and with strict supervision. One student says that it has been nice not having screen time at school because she loves to read and write. But it wasn't just the lack of attention span children were developing, they were also developing low self-esteem and poor mental health due to the amount of time spent on devices.

kids, intelligence, sharp kids, generations, education, cognitive abilities Students focused and ready to learn in the classroom.Photo credit: Canva

The data showing the negative impact of screens on teens' brains has prompted a nationwide change in Denmark that extends outside of the classroom. Afterschool activities are eliminating or extremely limiting electronic use. There is also a national No Phone Day that encourages everyone to put away their devices for the day, and Imran Rashid, a physician and digital health expert, is petitioning parliament to ban social media use for children under the age of 15. The no phone movement in Denmark is a nationwide effort that hopes to right the ship before another generation feels the effects.

dementia, dementia village, elder care, memory care, alzheimer's disease

In a dementia village, people get to choose where they go.

No matter how much caregivers may want to keep a loved one with dementia in their home, it's not always feasible. Living with dementia is not easy, nor is living with someone who has dementia. But moving a loved one with dementia into a traditional care facility isn't always ideal, either. It can be difficult to find a suitable living situation that ticks all the boxes for what a family and their loved one would want.

That's where a "dementia village" comes in as an alternative. Instead of trying to fit a person with dementia into a living situation that either isn't designed for them or is overly focused on their limitations, a dementia village is an environment designed specifically to help people with severe dementia feel safe and free and live as normal a life as possible.


- YouTube www.youtube.com

The Hogeweyk was the world's first dementia village, founded in 2009. Since then, the idea has been replicated in dozens of locations all over the world. The concept is quite simple: A full, self-contained neighborhood where people with dementia can walk around freely without fear of getting lost, where everyone from shopkeepers to restaurant servers to salon workers are trained in dementia care, and where people who are losing their memory to dementia diseases are treated as people who still have aspirations.

Eloy van Hal, one of the founders of the Hogeweyk, explained to Vox how the guiding principle of the village is "normalcy." Traditional nursing homes keep all residents under one roof, and they are subject to do whatever program the institution provides for them. In the Hogeweyk, people live in small groups of six or seven in apartments with furnishings like they'd have at home. Distinct landmarks in the public space help residents know where they are, and putting a theater, grocery store, barber shop, etc. in separate buildings encourage movement through the neighborhood.

"It's about choice, choice, choice, where you want to be during the whole day and with whom," said van Hal. The idea is to balance safe design with controlled risk, allowing for as much of a normal life as possible.

dementia, dementia village, elder care, memory care, alzheimer's disease Every worker in a dementia village is trained in dementia care.Photo credit: Canva

The one downside to the village concept, of course, is cost. Without adequate funding assistance from governments, living in a dementia village can be prohibitively expensive.

Does it really make a difference for residents, though? Has it been proven that outcomes are better than traditional care models? With dozens of villages now being used around the world, research is ongoing, but the data from the Hogeweyk is promising. People in the comments of Vox's by Design video shared how such facilities have been life-changing for their loved ones and how traditional care doesn't always meet the needs of people with dementia.

"My grandmother had dementia and when her caretaker who was my grandfather (her husband) passed unexpectedly we had to scramble to get her into a memory care facility in the US. The first place she was in temporarily was so sad, I could see her spirit drain but after about a year we were able to get her into a "village" and the quality of life difference is nothing short of ASTOUNDING! She could function in a way that was familiar and comfortable to her and not be in a foreign hospital setting. The abrupt change from a home where they are familiar, to a clinical setting must be very disorienting and upsetting to these people. That side of my family had mental health issues and memory loss starts early, so I know it will happen to me to some extent and I only hope I can have people take care of me as well as in this Hogeweyk."

"I've worked in a nursing home through high school and college. While I can't say it was the worst place for dementia patients, it certainly did not work well for all of them. One patient once tried to wedge herself through the door begging to go outside with me and I even had patients confide in me that they hated being institutionalized, they missed being able to live a normal life, being part of a real community, and being able to come and go as they pleased. This concept is probably the closest thing possible to a normal life a dementia patient could ever have."

dementia, dementia village, elder care, memory care, alzheimer's disease In a dementia village, residents can live somewhat "normal" lives.Photo credit: Canva

"A relative of mine used to get aggressive, violent and angry when she would encounter a locked door in the institution she was in. She couldn't understand why there would be a locked room in what she understood to be 'her home', this would take a lot of calming down and management, only for her to discover another locked door, and kick off again. I love these village based models as they allow autonomy for residents, and have an individual experience. Just because someone has a brain disease doesn't mean they aren't entitled to the very best care. I hope the govt spends far more on these establishments in the future."

"As he said at the end, people with dementia are still people—even if there is proven to be no benefits to this model over a care home, I would much prefer to have dignity in my final days than live in a clinical trap. Love all the incredible ideas the Netherlands come up with."

dementia, dementia village, elder care, memory care, alzheimer's disease A dementia village is a self-contained neighborhood with shops and places for people to go like a normal neighborhood. Photo credit: Canva

Dementia care is something Americans are going to have to look at closely. According to The Alzheimer's Association, the number of people living with Alzheimer's is set to nearly double from seven million to 13 million by the year 2050. As more of our elders require full-time care, the more we'll have to consider prioritizing putting resources into things like dementia villages.

Everyone deserves safety and a good quality of life. The Hogeweyk is a great example of what it looks like to view people with dementia as people first and to care for them accordingly.

This article originally appeared last year. It has been updated.

parenting, teens, raising teens, teen hangout, high school, game night for teens, activities for teens, parenthood

Amy White explains how her house became "the house" for her teens.

I grew up in "the house." In high school, my home was the designated place where my friends gathered, sometimes in big groups, sometimes just my small core squad. My three best friends spent the night there almost every Friday and/or Saturday night for four years straight. We devoured Totino's frozen pizzas by the dozen, inhaled soda, and laid waste to any snacks or leftovers that were brave enough to survive in the kitchen. Not only that, but my house was pretty small — four teenage boys took up a lot of space in the living room (the whole thing) and made a lot of noise playing video games deep into the night. It must have driven my parents and older brothers crazy. It's a wonder anyone put up with it.

Or so I thought when I was younger. When I became a parent myself, I started to understand a little more why my mom and dad were so willing to host and feed all my friends and me every single weekend. Why the outrageous grocery bill and constant chaos in the house were probably a small price to pay.


Mom explains how to make your house 'the house' where teenagers hang

One mom has perfectly encapsulated the value of turning your home into "the house" for your kids and their friends, and exactly how she did it for her family.

teens, teen house, teens hanging out, teens having fun, teenagers Teens hanging out in a living room.via Canva/Photos

Amy White shared a reel on Instagram showing her college-aged son hanging in her dining room with a group of friends playing cards. The text overlay reads "What makes your kids' high school friends want to come over, play cards & spend the night on their College Christmas Break." I think most parents can agree that we want our kids to keep coming home as long as possible! So how exactly did White pull this off?

Her explanation in the caption was spot-on.

First, White says that you have to start early. Become "the hang out house" in high school or even earlier. Then you have a better chance of holding onto the mantle into your kid's college years.


Next, be ready to stock the house with snacks and drinks, and don't make a fuss when your kid's friends have at it. "The kids knew we had food," she writes, "BUT they also knew I didn't care what they had. They knew they could eat anything in my pantry and fridge."

Third, and this is a big one, don't mistake being the "cool house" for being "the house." Some parents choose to allow their underage kids and friends to drink alcohol under their supervision, but you don't have to bend your morals and the law to lure the squad over to your place. Pizza and Coke is plenty to keep most teens happy. "We were not the house that served alcohol or even allowed the kids to bring alcohol to our house. And Guess What?? The kids still came and wanted to hang at our house!"

teens, teen house, teens hanging out, teens having fun, teenagers Teenagers eating pizza.via Canva/Photos

Fourth, always say Yes (as often as possible, anyway) when your kids want to have friends over. "They know my answer is 99% of the time YES," White writes. "You have to have your kids take the leadership of offering your home and if your home was 'open' to their friends in high school, they know it will be 'open' to their friends in college."

As a bonus tip, White pleas with parents not to worry about the mess having friends over makes. "I love a clean house and organization, BUT I would much rather have a crazy messy house for the kids where memories are made than a quiet house with nothing going on just to keep my house 'clean.'"

Should parents allow teens to drink at home?

There's an age-old debate over whether parents should allow teens to drink at home because it's better than if they do is unsupervised or keep their home dry as a bone. A recent study out of the University of Buffalo found that kids who grew up drinking at home had a greater chance of having addiction problems when they got older. "A robust relationship was found between parental permission to use alcohol during adolescence and increased alcohol use frequency and quantity, alcohol use disorder symptoms, and alcohol-related harms in young adulthood," the study says.

White writes, "It's worth being 'the house', so let go of control & get to know your kids friends." Commenters agreed.

White's video went viral to the tune of 8.5 million views and hundreds of comments. Parents shared their own experiences of what it's like being the default hang out house.

"Our house was the high school hangout for my son and friends... every weekend... I loved it!! Miss it now that they are all college graduates and have moved away. I love seeing them when they do come home for the holidays"

"A wise man once said don't be the house with the alcohol. Be the house with the food."

"Amy 1000% agree!!! My house is full of teenagers on the weekends and I love every bit of it. Even though I wake up to a kitchen that looked much different from when I left it"


teens, teen house, teens hanging out, teens having fun, teenagers Teenagers eating pizza.via Canva/Photos

"We never allowed alcohol, drugs, bad language, always respectful, and guess what, our house was always the house where the kids hung out. First my daughter, then my son. Through grade school, high school, then when my kids went out of state for college their college friends would come spend a couple weeks during the summer. I always thought of it this way, I loved knowing my kids friends and, who knows, maybe some of those kids, especially during the younger years, just maybe those kids just needed an adult to care. Anyway, it was always fun to have them here!"

"It used to crack me up when my daughter would bring over a bunch of her friends (girls and boys) in high school and instead of hanging out in the family room they all wanted to crowd into either the kitchen with me or our tiny office and happily share all the gossip with me."

Experts say that knowing your kids' friends, and their parents, can have huge benefits. Not only will it bring you the peace of mind of knowing where your kid is and who they're with when they get to those crucial high school years, it has been shown to tangibly improve kids ability to create positive relationships and problem-solve collaboratively. Plus, it can actually be really fun! Kids and teens are the funniest, silliest, most interesting people on the planet. Having a house full of them is messy and loud, but it's always a good time.

One caveat: "don’t feel bad if your house isn’t the chosen house," one commenter reminds us. "Just be happy your kid has a good group of friends and be thankful they have somewhere safe to hang out."

This article originally appeared last year.

text in mirrors reversed, text backward in mirrors, how mirrors work, mirrors, science

Why is text reversed in mirrors?

Have you ever wondered why text shows up backwards in a mirror? It's confusing to our brains because it doesn't seem like anything else is flipped like that. If we turn our head, it doesn't move the opposite direction in the mirror. Or does it? After all, right-handed you is actually left-handed you in the mirror. Right? (Wait, is that right?)

Mirrors can be confusing despite not being very complicated. A mirror image is simply a reflection of what's in front of it. But when someone else is looking at us head on, they don't see text in reverse, so why don't we see what other people see when we see ourselves in a mirror?


mirrors, mirror, how mirrors work, mirror image, text in mirrors Woman smiling in a mirror.Canva Photos.

(If you think this is a super stupid question with a super obvious answer, congratulations. Pat yourself on the back and scootch along so the folks who don't fully grasp the physics of mirrors can enjoy a demonstration that makes it a little easier to understand.)

"Why do mirrors reverse text?" asks the creator behind @humanteneleven on YouTube. "You might think it's just a property of mirrors—they flip things from left to right—but that's not true." He then picks up a metal arrow to show that it points the same direction in the mirror as it does in real life. So why is the text flipped when the arrow isn't?

- YouTube youtu.be

He then holds up a book to show how the text on the book cover appears backwards, just like the shirt. But when he holds up a Ziploc bag with the word "HELLO" written on it, the word shows up properly.

Why? How?

It's because he had to flip the book over to see the cover text in the mirror. The baggy, on the other hand, he could just hold up and see the letters through the transparent plastic, just as we see them in real life. If he flips the baggy over like he did the book, the text shows up backwards in the mirror, just like it does in real life.

"So it's actually not the mirror that's flipping anything from left to right," he says. "It's the human."

People appreciated the simple, straightforward explanation and demonstrations.

"One of the most insightful demonstrations I've seen. It's simple and explains the phenomenon. Well done!"

"While I've heard this explanation many times before, I've only recently seen it demonstrated with text-on-transparency, which is what really makes it click. Great video!"

"Love these sorts of demonstrations. It’s a bit of a complicated one, but I love seeing how different people's minds work when explaining simple things like this. My kid explains it with “left is on the left, right is on the right, things aren’t flipped, they are mirrored” but it’s true that you are the one who flips things and I’ve never thought of it that way before."

"Oh my God, I haven't understood explanations from physics videos about why mirrors flip but this, gosh this helps."

Mirrors have been hilariously befuddling people in other videos as they try to figure out how the mirror "knows" what's behind a barrier placed in front of objects.

@sarahcoome

this is kinda creepy 👀 #mirror #relatable #creepy

Is this something all of us should probably have learned in high school? Yes. Do all of us remember everything we learned in high school? No. Does the scientific explanation make perfect sense to everyone even if it's explained in detail? Um, no.

Like the reversed text question, having a simplified explanation that doesn't fully get into the nitty gritty physics and geometry of how mirrors work is helpful for some folks.

- YouTube youtu.be

For those who want a bit more scientific substance to their explanations, this next video does a good job of giving a bit more detail while still keeping the explanation simple. It even uses a visual diagram to explain:

- YouTube youtu.be

And for those who say, "This is so basic! How do people not understand this?" here's a video that really does get into the nitty gritty physics and geometry of how mirrors work, diving into ray and wave optics, photons, wave functions, probability, and quantum mechanics. It's only 12 minutes, and it manages to entertain while explaining, but it certainly blows the notion that understanding mirrors is super simple.

- YouTube youtu.be

As one commenter wrote, "I thought I understood mirrors. I understand mirrors even less now. And that's a compliment."

Isn't science fun?

This article originally appeared last year.

dog experiments, dog tongue cleaner than humans, experiments by kids, cool science, dogs, fun science, experiments, science

A young teen boy holding a beagle.

Dogs come in a wide variety of breeds, along with their own unique personalities and needs. They can be guardians, helpful workers, loyal friends, snuggly companions, but there's one thing almost all dogs have in common: Licking.

Sure, some dogs lick way more than others, but it's rare to find a dog who never licks anyone or anything. Many dogs communicate and show affection by licking, which is sweet—if a little gross—depending on how slobbery they are. There's a common saying that dogs' mouths are cleaner than humans', which is a bit hard to believe when you see what some dogs put in their mouths, but it is true?


What does science say about dog tongues and saliva? Is a dog licking our face something we should worry about?


dog experiments, dog tongue cleaner than humans, experiments by kids, cool science, dogs, fun science, experiments, science A man being licked by a golden retreiver. Photo credit: Canva

It turns out, the answer to whether a dog's mouth is cleaner than ours isn't super straightforward.

An 8th grader named Abby tackled this question in a science experiment that won her a Young Naturalists Award from the American Museum of Natural History in 2011. Her family had gotten a dog and her mom kept telling her not to let the dog lick her face because dog mouths are full of bacteria. Instead of arguing, Abby decided to find out herself if this was true.

"I hypothesized that human tongues would be cleaner than dog tongues," she wrote. "I thought this because humans brush their teeth at least once a day. I hypothesized that dogs' tongues would be dirty because they were always licking dirty things like garbage."

After diving into the research about bacteria that live in and on humans and dogs, Abby decided she had a testable hypothesis. But this wasn't any old middle school science experiment. She applied for and got a grant to the State Hygienic Lab at the University of Iowa, where she was assigned a mentor to work with her.

You can read the nitty-gritty details of her experiment here, but it involved a lab, swabs, agar plates, and more. Here was the conclusion:

dog experiments, dog tongue cleaner than humans, experiments by kids, cool science, dogs, fun science, experiments, science A dog's tongue close-up. Photo credit: Canva

"I concluded that dog and human mouth flora are very different. (Flora means the bacteria found in a mouth or anywhere else.) The bacteria found in human mouths are more similar to another human's oral bacteria than the bacteria found in a dog's mouth.

"I also concluded that dogs' mouths are cleaner than humans' in some ways, and dirtier in other ways. Humans have more bacteria in their mouths than dogs do, based on the total number of bacteria. Most of the humans had a 'moderate' number of bacteria, and most of the dogs had 'few' bacteria. A possible explanation of this might be that dogs pant a lot, and maybe while panting, bacteria falls off their tongues along with their saliva. But dogs had more types of bacteria. The average number of different bacterial colonies in a dog's mouth was about 5.7. The average number of different bacterial colonies in a human's mouth was about 4.1. I think this is so because dogs sniff and lick a variety of things, like carpets, floors, chairs, grass, etc., so they pick up bacteria from many places."

But what about the licking of our faces? That's a bit of a subjective call, but Abby's results gave her some peace of mind:

"In conclusion, will I let my dog continue to lick me? The answer to the question is yes!" she wrote. "I will feel guiltless about letting my dog lick me because I found out that human and dog oral bacteria are different, so my dog's oral bacteria present no harm to me."

What do the experts say?

According to Colin Harvey, professor at the University of Pennsylvania’s School of Veterinary Medicine and executive secretary at the American Veterinary Dental College, comparing dogs' mouths to humans' mouth is "like comparing apples to oranges." As Abby found, the microbes in a dog's mouth are very different than those in a human's.

The American Kennel Club elaborates:

"Most of the bacteria in your dog’s mouth aren’t zoonotic, which means you probably won’t get a disease from a big old doggy kiss. There are exceptions to this. Dogs that eat a raw diet are at an increased risk of contracting salmonella, which can be spread to humans. You also probably shouldn’t share kisses with a dog that regularly raids the litter box.

In other words, kissing your dog is less risky than kissing another human, but that doesn’t mean that your dog’s mouth is necessarily cleaner than a human’s—they just have a mostly incompatible set of germs."

Keeping your dog's mouth healthy through regular teeth cleaning and dental check-ups can also help prevent issues that could potentially come from dog licks.

dog experiments, dog tongue cleaner than humans, experiments by kids, cool science, dogs, fun science, experiments, science A golden retreiver getting their teeth brushed. Photo credit: Canva

So there you have it. If your dog doesn't eat a raw diet and doesn't go snacking in the cat box (or some other equally fecal-bacteria-ridden place), their kisses are probably not going to hurt you. Guilt-free pooch smooches for the win!

This article originally appeared last year.