Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.

Why can’t I wiggle my toes individually, like I can with my fingers? – Vincent, age 15, Arlington, Virginia

One of my favorite activities is going to the zoo where I live in Knoxville when it first opens and the animals are most active. On one recent weekend, I headed to the chimpanzees first.

Their breakfast was still scattered around their enclosure for them to find. Ripley, one of the male chimpanzees, quickly gathered up some fruits and vegetables, sometimes using his feet almost like hands. After he ate, he used his feet to grab the fire hoses hanging around the enclosure and even held pieces of straw and other toys in his toes.

I found myself feeling a bit envious. Why can’t people use our feet like this, quickly and easily grasping things with our toes just as easily as we do with our fingers?

I’m a biological anthropologist who studies the biomechanics of the modern human foot and ankle, using mechanical principles of movement to understand how forces affect the shape of our bodies and how humans have changed over time. Your muscles, brain and how human feet evolved all play a part in why you can’t wiggle individual toes one by one.

Comparing humans to a close relative

Humans are primates, which means we belong to the same group of animals that includes apes like Riley the chimp. In fact, chimpanzees are our closest genetic relatives, sharing almost 98.8% of our DNA.

Evolution is part of the answer to why chimpanzees have such dexterous toes while ours seem much more clumsy.

Our very ancient ancestors probably moved around the way chimpanzees do, using both their arms and legs. But over time our lineage started walking on two legs. Human feet needed to change to help us stay balanced and to support our bodies as we walk upright. It became less important for our toes to move individually than to keep us from toppling over as we moved through the world in this new way.

Human hands became more important for things such as using tools, one of the hallmark skills of human beings. Over time, our fingers became better at moving on their own. People use their hands to do lots of things, such as drawing, texting or playing a musical instrument. Even typing this article is possible only because my fingers can make small, careful and controlled movements.

People’s feet and hands evolved for different purposes.

Muscles that move your fingers or toes

Evolution brought these differences about by physically adapting our muscles, bones and tendons to better support walking and balance. Hands and feet have similar anatomy; both have five fingers or toes that are moved by muscles and tendons. The human foot contains 29 muscles that all work to help you walk and stay balanced when you stand. In comparison, a hand has 34 muscles.

Most of the muscles of your foot let you point your toes down, like when you stand on tiptoes, or lift them up, like when you walk on your heels. These muscles also help feet roll slightly inward or outward, which lets you keep your balance on uneven ground. All these movements work together to help you walk and run safely.

The big toe on each foot is special because it helps push your body forward when you walk and has extra muscles just for its movement. The other four toes don’t have their own separate muscles. A few main muscles in the bottom of your foot and in your calf move all four toes at once. Because they share muscles, those toes can wiggle, but not very independently like your fingers can. The calf muscles also have long tendons that reach into the foot; they’re better at keeping you steady and helping you walk than at making tiny, precise movements.

In contrast, six main muscle groups help move each finger. The fingers share these muscles, which sit mostly in the forearm and connect to the fingers by tendons. The thumb and pinky have extra muscles that let you grip and hold objects more easily. All of these muscles are specialized to allow careful, controlled movements, such as writing.

So, yes, I have more muscles dedicated to moving my fingers, but that is not the only reason I can’t wiggle my toes one by one.

Divvying up brain power

You also need to look inside your brain to understand why toes and fingers work differently. Part of your brain called the motor cortex tells your body how to move. It’s made of cells called neurons that act like tiny messengers, sending signals to the rest of your body.

Your motor cortex devotes many more neurons to controlling your fingers than your toes, so it can send much more detailed instructions to your fingers. Because of the way your motor cortex is organized, it takes more “brain power,” meaning more signals and more activity, to move your fingers than your toes.

Even though you can’t grab things with your feet like Ripley the chimp can, you can understand why.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Steven Lautzenheiser, Assistant Professor of Biological Anthropology, University of Tennessee

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

Are there thunderstorms on Mars? – Cade, age 7, Houston, Texas

Mars is a very dry planet with very little water in its atmosphere and hardly any clouds, so you might not expect it to have storms. Yet, there is lightning and thunder on Mars – although not with rain, nor with the same gusto as weather on Earth.

More than 10 years ago, my planetary science colleagues and I found the first evidence for lightning strikes on Mars. In the following decade, other researchers have continued to study what lightning might be like on the red planet. In November 2025, a Mars rover first captured the spectacular sounds of lightning sparking on the Martian surface.

Lightning on Mars

On Earth, lightning is an electric discharge that begins inside big clouds.

But because Mars is so dry, it doesn’t have clouds of water – instead, it has clouds of dust. With little water to weigh down dirt on Mars, dust clouds can quickly grow into huge, windy dust storms a few times taller than Earth’s tallest thunderstorms.

When smaller dust particles and larger sand particles collide with each other while being whipped around by these storms, they pick up a static charge. Smaller dust particles take on a negative charge, while larger sand particles become positive. The smaller dust particles are lighter and will float higher, while the heavier sand tends to fall closer to the ground.

Because oppositely charged particles don’t like to be apart, eventually the energy building between the negative charges higher up in the dust storm and the positive charges closer to the ground becomes too great and is released as electricity – similar to lightning.

The air around the electricity rapidly warms up and expands – on Earth, this creates the shock waves that you hear as thunder.

Nobody has seen a flash of lightning on Mars, but we suspect it’s more like the glow from a neon light rather than a powerful lightning bolt. The atmosphere near the surface of Mars is about 100 times less dense than on Earth: It’s much more similar to the air inside neon lights.

Releasing radio waves

Besides shock waves and visible light, lightning also produces other types of waves that the human eye can’t see: X-ray and radio waves. The ground and the top of the atmosphere both conduct electricity well, so they guide these radio waves and cause them to produce signals with specific radio frequencies. It’s kind of like how you might tune into specific radio channels for news or music, but instead of different channels, scientists can identify the radio waves coming from lightning.

While nobody has ever seen visible light from Martian lightning, we have heard something similar to the radio waves created by lightning on Earth. That’s the noise that the Perseverance rover reported at the end of 2025. They sound like electric sparks do on Earth. The rover recorded these signals on a microphone as small, sandy tornadoes passed by.

Searching for Martian lightning

When my colleagues and I went hunting for lightning on Mars a decade ago, we knew the red planet emitted more radio waves during dust storm seasons. So, we searched for modest increases in radio signals from Mars using the large radio dishes that NASA uses to talk to its spacecraft. The dishes function like big ears that listen for faint radio signals from spacecraft far from Earth.

We spent from five to eight hours every day listening to Mars for three weeks. Eventually, we found the signals we were looking for: radio bursts with frequencies that matched up with the radio waves that lightning on Earth can create.

To find the particular source of these lightning-like signals, we searched for dust storms in pictures taken by spacecraft orbiting Mars. We matched a dust storm nearly 25 miles (40 kilometers) tall to the time when we’d heard the radio signals.

Learning about lightning on Mars helps scientists understand whether the planet could have once hosted extraterrestrial life. Lightning may have helped create life on Earth by converting molecules of nitrogen and carbon dioxide in the atmosphere into amino acids. Amino acids make up proteins, tens of thousands of which are found in a human body.

So, Mars does have storms, but they’re far drier and dustier than the thunderstorms on Earth. Scientists are continually studying lightning on Mars to better understand the geology of the red planet and its potential to host living organisms.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Editor’s note: This story was updated on Jan. 27 to reflect the static charges of particles during a dust storm.

Nilton O. Rennó, Professor of Climate and Space Sciences Engineering, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Curious Kids is a series for children in which we ask experts to answer questions from kids.

What is the smallest thing in the universe that actually exists? – Mimi, 12, Abeokuta, Nigeria

To find an answer, we asked physicist Omololu Akin-Ojo, who teaches this subject. A physicist is someone who studies physics. Physics is the science of energy, forces and particles. We study physics in order to be able to manipulate energy, forces and particles for our benefit. For example, to create electricity or motion to move a car.

So, what’s the smallest thing in the universe?

Thank you for your question.

Take a piece of anything, cut it into tiny pieces, cut the tiny pieces into tinier pieces (at this point you might need a magnifying glass or microscope to see what you are cutting), and continue to cut them into yet tinier pieces. After a point, you will not be able to see the particles, even with microscopes. Suppose we can continue this process until we get to a point where we cannot cut the tiny pieces into tinier pieces any longer.

Then we have reached the level of the atom. An atom is so small you can’t see it, but atoms are everywhere.

To start with, what is an atom?

The word “atom” is from the Greek word atomos, which means “uncuttable”. This is the smallest particle in the universe that behaves “normally”. Normal behaviour for a particular atom means that it is neutral (not electrically attracted to other particles) and still retains chemical properties from the substance from which it was cut.

However, scientists have found that the atom is made up of even tinier particles: electrons and the nucleus.

The electron is one of the tiniest particles that exists.

Inside the nucleus, we have protons and neutrons and inside these there are quarks. Quarks are as tiny as electrons. When atoms break up, other particles, called neutrinos, may be released. Although they are not tinier than electrons, neutrinos might weigh less than electrons – we are not certain.

Scientists have also been able to smash particles together by giving them a lot of energy and making them collide with one another. When particles smash into each other, sometimes we get other particles that are as tiny as electrons but weigh more than electrons. Their names are muons, tauons and pions. We cannot see them with our naked eyes, but scientists have been able to create environments such that when these particles move in them, we can see their paths.

So, Mimi, the electron is the tiniest particle. Then there are neutrinos, which are as small (but may or may not weigh more). Then we have quarks (which are found inside protons or neutrons) and also we have muons, tauons and pions, which are as small as electrons but weigh more.

Everything in the world is made up of all these tiny pieces. They’re everywhere.

Omololu Akin-Ojo, Senior Lecturer, University of Ibadan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

What is Bluetooth? – Henry, age 13, Somerville, Massachusetts

How do headphones, toys, gadgets and other devices talk to each other without any wires? Many of them connect with Bluetooth. It’s a technology that allows different devices to communicate wirelessly. Think of it as a device’s voice that it uses to share information.

Bluetooth works by sending radio wave signals between devices. Radio waves are electromagnetic waves, which are a type of energy that moves from one place to another. Other kinds of electromagnetic waves include heat, light and X-rays. Radio waves can carry information, from the sights and sounds on a TV to data on a laptop. As an example, your music player sends the music through these invisible waves to your headphones.

I’m an electrical and computer engineer and I study wireless technologies. Every device that uses Bluetooth contains a set of computer chips that send and receive these radio waves.

Connecting through Bluetooth starts with a process called pairing. Pairing is like first introductions between two people, where they acknowledge each other and agree to talk to each other. Once paired, the devices remember each other and don’t have to be paired the next time.

Bluetooth is everywhere! Over 5 billion Bluetooth devices were sold worldwide in 2025. It’s in headphones for listening to wireless music and in video games that let you play with wireless controllers. Smartphones and tablets use Bluetooth to share photos, videos and files with friends. Smartwatches connect to your phone to get notifications and track your fitness. In cars, Bluetooth lets you play music from your phone and enables hands-free calls.

Bluetooth is named after a Scandinavian king, Harald Bluetooth Gormsson, who united parts of the Nordic region in the 900s, because the technology unites different devices. The symbol for Bluetooth comes from a combination of two ancient Nordic runes, or symbols, for the king’s initials.

Bluetooth vs. Wi-Fi

Bluetooth and Wi-Fi complement each other, serving different purposes in our everyday connected world.

Bluetooth is great for things that need moderate but not superfast speeds, such as streaming music or connecting devices. For faster needs, people use Wi-Fi. Bluetooth is not ideal for transferring large files or streaming high-definition video. But for most everyday tasks, it’s pretty capable.

Bluetooth is ideal for short-range connections up to 30 feet, so mostly when the two connected devices are in the same room. Wi-Fi, on the other hand, is designed for longer-range communication, up to 300 feet – for example, within a house or school building.

Bluetooth connects devices directly to each other without needing to connect to the internet. But if you need high-speed internet access or to create a local network of multiple devices, Wi-Fi is the way to go.

Bluetooth is good for when it’s important to use low amounts of power to connect devices, like for wireless devices that run on batteries. Wi-Fi consumes more power, so the Wi-Fi routers that connect devices to each other and the internet typically have to be plugged into an outlet.

From blasting music to tracking your steps or sharing a meme with a friend, Bluetooth makes it faster and easier. So the next time you use your wireless headphones, you’ll know the technology behind the magical flow of songs through the airwaves.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Shreyas Sen, Associate Professor of Electrical and Computer Engineering, Purdue University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

What are those orange balls on some power lines? – Maggie, age 8, West Chester, Pennsylvania

Have you ever looked up while driving on a highway and spotted those big orange balls hanging on power lines? They look a bit like giant toy beads strung along the electric wires.

What in the world are those overgrown basketballs doing up there?

I’m a professor who teaches about and researches power systems, the big networks that move electricity from power plants to our homes, schools and businesses.

Those big orange balls don’t help with electricity flow or improve the efficiency of the power lines, but they do have a very important job. Officially called aviation marker balls or spherical markers, they’re there to help pilots see power lines so airplanes and helicopters don’t crash into them. They’re like bright warning signs in the sky, protecting pilots, passengers and people on the ground below.

Big round warning signs in the sky

Power lines can be very hard to see from an airplane or helicopter, especially when pilots are flying low. Thin metal wires can visually blend into the background of nature.

The orange balls help the lines stand out. You can think of them as being like reflective tape on a bike – just a little something simple that helps people notice a danger before it’s too late.

Orange isn’t a random choice. This vibrant color is very visible to the human eye and especially stands out against the more muted colors of nature – blue sky, green trees or gray clouds. Sometimes the balls are red or white, or even striped, but orange is the most common because it works well in most lighting conditions.

Aviation safety rules in many countries explain which colors should be used so pilots can quickly recognize hazards. Organizations like the U.S. Federal Aviation Administration publish guidelines you can check out about marking obstacles near flight paths.

These balls may look like slightly oversized ping-pong balls from your perspective on the ground. But most are actually much bigger, about the size of a large beach ball, roughly 2 to 3 feet (0.6 to 1 meter) across. Each one can weigh 10 to 25 pounds (4.5 to 11 kilograms), about as heavy as a large backpack full of books.

They’re usually made from strong plastic or fiberglass, similar to materials used in boats or playground equipment. That way, they can survive years of sun, rain, snow, wind – and even the occasional bird landing on them.

Even though they sit on wires that carry huge amounts of electricity, the balls themselves are not energized. They’re made of insulating materials, so electricity does not flow through them.

Why are there so many wires up there?

High-voltage power lines are like highways for electric power, carrying electricity from the power plants where it is generated to the places where it is used.

The wires are strung between sturdy metal towers or wooden poles that are very tall to keep dangerous high-voltage electric wires high up in the sky, far away from people on the ground. This design makes it safe to walk, play and drive underneath them. Some transmission towers, especially for very high-voltage lines, can be as tall as a 15-story building.

If you look closely at big transmission lines, you’ll often see three thick wires, sometimes with an additional thinner one on top that’s called a shield wire. Because the shield wire sits higher, lightning is more likely to hit it first, protecting the other wires from a strong blast of electricity that can damage equipment or cause power outages. The shield wire is connected to the ground, so a lightning strike’s electricity can flow safely down the tower and into the earth.

The three main wires work together to carry electricity in a steady rhythm. By sharing the job among three wires instead of one, the system can move more energy with less waste, making it more efficient.

Clamping the balls to the wires

Installing the aviation marker balls is a job for specially trained crews, often working from helicopters. The power line usually stays turned on while the work is being done, so safety rules and careful planning are critical. The ball comes in two halves that clamp around the wire and bolt together tightly.

Once installed, these balls can last 10 to 15 years, depending on weather and conditions. They don’t need much maintenance, but utilities inspect them from time to time to make sure they haven’t cracked or faded too much.

Not every transmission line needs the markers. Usually only places where aircraft are more likely to fly low – such as near rivers, valleys, airports or helicopter routes – will use these brightly colored balls. Most neighborhood power lines are too low to need markers.

Next time you spot those bright orange dots in the sky, you’ll know: They’re not electrical equipment, and their color isn’t random. They’re simple, clever tools helping keep our busy world a little safer.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Rui Bo, Associate Professor of Electrical and Computer Engineering, Missouri University of Science and Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.