Have you ever seen a bug walking up a wall and thought, “Wow, that’s amazing!”? Bugs can walk up and down walls and even hang upside down on ceilings, just like superheroes. They don’t need ropes or special powers to do it. Imagine if you could walk up a wall like that!
Let’s take a closer look at how bugs manage this incredible feat. For example, Asian weaver ants can climb walls while carrying more than a hundred times their body weight. That’s like you climbing a building with a hundred of your friends hanging on!
It’s not just bugs that can do this. Tree frogs can climb trees and walls, even in the rain, without slipping. So, how do they stick to walls?
When I first thought about how bugs stick to walls, I imagined they might use something sticky like glue. And in a way, they do! If you look closely at a fly’s feet, you’ll see they’re covered in tiny hairs. These hairs produce a liquid that helps them stick to walls. It’s not exactly glue, but it works similarly, like how a wet cup can stick to a coaster.
Other creatures like ants, grasshoppers, bees, and tree frogs also use this liquid to stick to surfaces. But could humans do the same thing?
There are adhesives strong enough to let us stick to walls, but the problem is getting unstuck. Insects are small and light, so they don’t need much sticking power. They can easily move their feet to unstick themselves. Humans, however, are much heavier, so we’d need a very strong adhesive. But then, it would be too strong to lift our hands again!
Geckos are the heaviest animals that can walk on walls. They can even hang upside down using just one toe! Surprisingly, their toes aren’t wet or sticky. Instead, geckos have tiny hairs on their toes called setae. These hairs create an invisible force called the Van der Waals force, which helps them stick to walls.
This force is similar to how your hair might stick to a balloon after you rub it. It’s like having little magnets on their feet. Spiders also use this invisible force to stick to surfaces.
Scientists are trying to create something similar for humans. Students at Stanford University have developed “gecko gloves” that mimic how geckos climb. These gloves have tiny bendy spikes that stick when pressed down but release when lifted, just like gecko toes.
So far, these gloves only work on glass, but they could be useful for things like helping astronauts grab onto objects in space.
That’s all for this week’s question. Thanks for asking! Remember, there are mysteries all around us. Stay curious and keep exploring!
Try creating your own version of “sticky feet” using materials like tape, glue, or Velcro. Test different materials to see which one allows you to climb a small incline or stick to a vertical surface. Discuss with your classmates why some materials work better than others.
Find a bug, like an ant or a fly, and observe how it moves on different surfaces. Draw a detailed picture of its feet and label any special features you notice. Share your drawing with the class and explain how these features might help the bug stick to surfaces.
Use balloons to explore the Van der Waals force. Rub a balloon on your hair and see how it sticks to different surfaces. Write down your observations and discuss how this force might help geckos and spiders stick to walls.
Imagine you are an engineer tasked with designing a glove that allows humans to climb walls like geckos. Draw your design and list the materials you would use. Present your design to the class and explain how it mimics the gecko’s ability to stick to surfaces.
Research a real-life application of adhesive technology inspired by nature, such as “gecko tape” or “gecko gloves.” Create a short presentation to share with the class, explaining how this technology works and its potential uses.
**Sanitized Transcript:**
(phone ringing) – Hi Doug. – Hi, Sophie. I have a question. Can people often walk on walls? – That’s a great question. I’m sure you’ve seen bugs walk on walls. And if you’re like me, you don’t really think much about it. It’s like it’s no big deal. But stop for a second and think about just how amazing that is. When a bug is doing this, it’s actually walking up and down walls and hanging upside down on the ceiling. Just like a superhero. Just like Spider-Man. And they’re doing this without using ropes or special powers or special effects. I mean, have you tried walking up a wall lately? If you have, you probably weren’t very successful, and yet many different kinds of bugs do this all the time.
Like check out these, they’re called Asian weaver ants. Not only can they climb up walls, they can do it while carrying more than a hundred times their body weight. That would be like you climbing up the side of a building while a hundred of your friends hang on for the ride. And it’s not only bugs that can walk on walls and hang upside down on ceilings; have a look at this tree frog. It can climb up trees or walls even in the pouring rain without sliding. In fact, they even stick better in the rain. So if bugs and other animals like tree frogs can do it, couldn’t we?
Before I say anything more, I’m curious. What do you think? Do you think people could ever walk on walls and how would they do it? Now would be a good time to pause the video and discuss. Okay, you ready? Well, in order to answer this question, it might help to learn more about how animals stick to walls. When I was thinking about that, I immediately thought they must use something sticky, like glue. Like, do bugs that can walk up walls have glue on their feet? Well, sort of. Check out this fly; look closely at its feet. You notice something? A fly’s foot is covered in tiny hairs. Scientists have found out that those hairs make a liquid that helps their feet stick to tiny bumps on a wall or ceiling. It’s not the same ingredients as in glue, but the liquid does help them stick to the wall. Kind of like the way water will make a cup stick to a coaster or a piece of paper when you lift it up.
And flies aren’t the only living things that use this method. Other creatures like ants, grasshoppers, bees, and even tree frogs use liquid to stick to walls too. So that makes you think, could humans do the same thing? Like, could we put some kind of glue or liquid on our shoes to help us walk up walls? Well, there actually are types of adhesives that are strong enough to allow us to stick to a wall or hang upside down. But people soon discovered the hardest challenge isn’t sticking to a wall; it’s unsticking.
You see, the thing about insects, like flies and ants, is that the liquid on their feet is sticky enough to keep them on the wall, but not sticky enough to get them stuck. That’s okay because they don’t need that much sticking power because they’re so small and don’t weigh that much. All they have to do is start to move the position of their feet, and they get unstuck again. They can walk while staying stuck on a wall or ceiling. But human beings are way heavier than flies or ants—too heavy. In order to stick to a wall, you need some really strong adhesive to hold your weight. But for the strength of that adhesive, it would be too strong to be able to lift your hands again.
Okay, so sticking to walls like flies might not work. But are there any other wall-crawling animals we can get ideas from? And are there slightly heavier animals that we could learn something from? There are. You see this gecko? Geckos are the heaviest animals on earth that are able to walk on walls, and they’re really good at it. So good that they can even hang upside down from the ceiling using only one of their toes. But here’s what’s most surprising. If you touch a gecko’s toes, you’ll soon discover that they aren’t wet or sticky at all. Geckos somehow stick to walls differently than flies do.
So how do they do it? Scientists have discovered once again that the sticking power comes from hair. Take a look up close; see all those hairs? Just like flies, gecko toe pads are covered with hundreds of tiny hairs called setae. And each of those hairs has even tinier hairs sprouting from their tips. Now these hairs don’t have any liquid on them to help them stick like flies do. But they do have a sticking power—in fact, even more than flies. Scientists have discovered that the hairs on a gecko’s toes can create an invisible pulling force called the Van der Waals force. That might sound really strange, but there are other invisible forces you’ve probably noticed yourself.
Like, if you’ve ever rubbed your head on a balloon, have you ever noticed when you do that your hair gets pulled invisibly toward it, almost like a magnet? The Van der Waals force is kind of like that. You’ll get to study more about this in high school science class, but each of the hairs on a gecko’s toes has this invisible pulling force that pulls a gecko’s toe pad towards the wall. Not hugely different from how your hair gets pulled toward a balloon or how a magnet gets pulled toward another magnet. So it’s almost as if a gecko has little magnets on its feet. Notice that’s a lot different than the sticky liquid that a lot of bugs use. Other creatures like spiders have this invisible sticking power on the hairs of their feet too.
So could human beings copy geckos and spiders and use this invisible sticking force to stick to walls? Well, maybe. Amazingly, students from Stanford University are trying to invent something that could work. They carefully studied the way geckos climb walls and developed something called gecko gloves. Just like spiders and gecko’s feet, it doesn’t use magnets or electricity. And when you touch it, it doesn’t feel sticky at all. But on each pad, there are lots and lots of tiny bendy spikes, kind of like hairs. When you press down and flatten them out, the gloves stick, but when you lift them up, the stickiness stops—a lot like a gecko’s toes.
The only problem is, so far they’ve only been able to make this work on glass. But as long as it’s a glass surface, like a window, it is now possible for human beings to climb up walls. In addition to being amazing to see and fun to do, there might even be some useful things these gloves can do, like helping astronauts grab onto things when they’re in space without floating away.
That’s all for this week’s question. Thanks, Sophie, for asking it. Now for the next episode, I reached into my question jar and picked up three questions sent in to me that I’m thinking about answering next. When this video is done playing, you’ll get to vote on one. You can choose from who invented microwaves, how are books made, or how does toothpaste clean your teeth? So submit your vote when the video is over; I want to hear from all of you watching. There are mysteries all around us. Stay curious and see you next week.
Bugs – Small insects that are often studied in biology for their diverse characteristics and behaviors. – Example sentence: Scientists study bugs to understand how they adapt to different environments.
Walls – Structures that can be natural or man-made, often used to separate or protect areas. – Example sentence: Some animals, like geckos, can climb walls using their special feet.
Sticky – Having a surface that can adhere to other surfaces, often used to describe substances or surfaces in nature. – Example sentence: The sticky pads on a frog’s feet help it climb trees and leaves.
Feet – The lower extremities of animals, used for walking, climbing, or holding onto surfaces. – Example sentence: Geckos have special feet that allow them to walk on ceilings and walls.
Geckos – A type of lizard known for its ability to climb smooth surfaces due to its unique toe pads. – Example sentence: Geckos use tiny hairs on their feet to stick to surfaces, even upside down.
Ants – Small insects that live in colonies and are known for their strength and teamwork. – Example sentence: Ants work together to build their nests and find food for the colony.
Frogs – Amphibians that are known for their jumping abilities and their life cycle, which includes a transformation from tadpoles. – Example sentence: Frogs have long legs that help them leap great distances to catch insects.
Scientists – People who study the natural world and conduct experiments to learn more about it. – Example sentence: Scientists use experiments to learn how geckos can climb smooth surfaces.
Force – A push or pull that can change the motion of an object, important in understanding how things move. – Example sentence: The force of gravity pulls objects toward the Earth, but geckos can resist it with their sticky feet.
Gloves – Protective coverings for the hands, often used in scientific experiments to handle materials safely. – Example sentence: Scientists wear gloves when handling chemicals to protect their skin.
