This is an article from Curious Kids, a series for children of all ages. The Conversation is asking young people to send in questions they’d like an expert to answer. All questions are welcome: find details on how to enter at the bottom.

What’s it like to be a fighter pilot? – Torben, aged eight, Sussex, UK

Thanks for your question, Torben. I’m a professor working at the University of Portsmouth’s Extreme Environments Laboratory, where we study how humans respond when going into space, mountains, deserts and the sea, as well as what it’s like to be in submarines, spacecraft and, of course, jet planes.

To be a fast jet pilot, you must be fit and smart, and able to do what’s needed, even when the going gets tough. You also get to wear some very special clothes, to protect your body while flying.

If you’re a fighter pilot, you’re not allowed to get air sick (which is a bit like getting car sick, in a plane). And you have to be the right height and weight to fit in the cockpit – and to jump out in emergencies.

Fighter jets can go 1,550 miles an hour: that’s more than twice the speed of sound, or 25 miles in a minute. So, if you live two miles from school, you could get home in less than five seconds in a fighter jet.

Only the best pilots in the world can fly a plane that goes so fast: you have to be able to think and act very quickly. To help you, modern jets listen to your voice, so you can tell them what to do – it’s called “voice command”.

Fast jets aren’t smooth to fly in, like the kind of planes you go on holiday in – they’re more like a fast fairground ride. You have to be strapped into your seat very tightly, so that you don’t get thrown around.

In fact, flying that fast and making lots of turns and dives can make you feel very sick. Can you imagine being sick, while wearing a mask and flying a plane at 1,000 miles an hour? That’s why fighter pilots have to be checked and trained to make sure they don’t get air sick.

Fast jet pilots also have to wear lots of special clothes to protect them in different situations. One thing they have to wear is a helmet to protect their head, and a mask with a microphone.

The mask is linked up to a system that can provide extra oxygen if anything goes wrong – after all, there’s less oxygen in the air when you’re flying very high, and humans need plenty of oxygen to breathe properly.

Standing on Earth, humans experience gravity at 1G (that’s one times the acceleration due to gravity). But when fighter jets make fast turns and rolls, the pilot can experience up to 9G (by comparison, roller coasters only produce 3-6G). That means they feel nine times heavier, which can be very unpleasant and would make most people black out.

To help with this, fighter pilots also wear special trousers that squeeze their legs tightly when they go round bends – this keeps the blood pumping up to their brain, to stop them from fainting: trust me, you don’t want to faint when flying a fast jet.

Fast jet pilots may also have to wear a flying suit, a life jacket and an “immersion suit” – that’s a suit which keeps you warm and dry, if you end up in the sea. They may also wear another suit to protect them from chemicals and other dangerous things.

All this kit and clothing can make a fighter pilot pretty hot. Plus the jet has a plastic lid and lots of very clever electronics, which can also heat up the cockpit. And when the plane goes fast through the air, it warms up due to friction – like when you rub your hands together fast.

To stay cool, fighter pilots can wear a special vest with long small tubes in it, which pump cold water around. Or, they can wear a suit next to their skin which has cold air blowing through it.

Pilots sit on a rocket-powered ejector seat, so if he or she gets into trouble, they can pull a handle and be blasted up into the air and away from the crashing plane.

Luckily, the seat has a parachute that opens up and lets them float down to the ground safely. But the force of the ejection actually makes them shorter for a little while afterwards.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:

* Email your question to curiouskids@theconversation.com
* Tell us on Twitter by tagging @ConversationUK with the hashtag #curiouskids, or
* Message us on Facebook.

Please tell us your name, age and which town or city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question, but we will do our best.

More Curious Kids articles, written by academic experts:

• How do the clouds stay up in the sky? – Samson, age four, London, UK

• If an insect is flying in a car while it is moving, does the insect have to move at the same speed? – Sarah, age 12, Strathfield, Australia

Michael Tipton, Professor of human and applied Physiology, University of Portsmouth

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

How did humans think about things, before they had language to think with? – Katie, aged 11, Sydney, Australia.

When we think, most of us have the feeling that words flow through our minds. If you stop to “listen” to your own thoughts, though, you will be amazed by how jumbled and chaotic they are. Our inner voice is something of an inner mumbler, creating a stream of disconnected words and phrases, rather than crystal-clear speech.

It is easy to imagine that we think in whatever language we speak – whether English, Spanish or Mandarian. But this is entirely wrong: language can express some of the results of our thinking, but it’s not the thinking itself.

Get it?

For example, think about what happens when you “get” a joke – like this award-winning joke by comedian Tim Vine:

I’ve decided to sell my hoover … well, it was just collecting dust.

Whether you laugh or groan (I rather like it), you need to do a lot of thinking to figure about what the joke even is.

You’ll need to remember that “collecting dust” is usually a snide remark about something that just sits in a cupboard, unused, so that dust settles on top of it. And you’ll realise that hoovers are made especially to suck up or collect dust, so it’s silly to criticise them for doing that. And that’s why the joke is funny.

Curious Kids is a series by The Conversation, which gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.com. We won’t be able to answer every question, but we’ll do our very best.

You must have reasoned along these lines, or you wouldn’t have “got” the joke. But I bet you reacted to the joke long before you had thought about what it meant using words.

And that is always true: the thoughts come first, and the expression of our thoughts in words, whether out loud, or in our heads, comes later and much more slowly – if at all.

Another example is the complex thinking you need to do when playing a fast-moving video game. You might sometimes say “oh no!” or “got you!” as you play, but if I were to try and make you say all your plans out loud in words, you would slow to a snail’s pace.

Smart species

So we can, and do, think about things without language, all the time. I don’t think in English, but I can report some of my thoughts in English, when I have the time to do so.

And it turns out that people who have aphasia – which means they sometimes can’t use or understand language, perhaps because they had a stroke – can do difficult maths, problem solving and reasoning tasks, so long, of course, as these don’t involve language.

You can test this yourself, by shutting down your inner voice. Simply repeat a single word quickly, either out loud or in your head – a trick psychologists call “articulatory suppression”.

You’ll find that while you’re repeating the word, you can no longer think using words, but you can still plan, reason and imagine, pretty much as normal.

But even though we don’t think in language, it does help us make our thoughts clear. In fact, the real magic of language is that it helps us share our thoughts with other people.

This means we don’t have to face the world all by ourselves – we can learn from the cleverness of the generations who have gone before us. This lets humans develop the really complicated scientific theories, laws, financial systems, histories and stories that make our lives so incredibly rich.

So we can, and do, think without language. But the invention of language is the special trick that makes us so amazingly smart as a species.

Children can have their own questions answered by experts – just send them in to Curious Kids, along with the child’s first name, age and town or city. You can:

• email curiouskids@theconversation.com
• tweet us @ConversationUK with #curiouskids
• DM us on Instagram @theconversationdotcom

Here are some more Curious Kids articles, written by academic experts:

• How do ripples form and why do they spread out across the water? – Rowan, aged six, UK.

• How does our brain send signals to our body? – Aarav, aged nine, Mumbai, India.

• How can we see what we are imagining but still see what’s in front of us? – Malala Yousafzai class, Globe Primary School, London, UK.

Nick Chater, Professor of Behavioural Science, Warwick Business School, University of Warwick

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

What do plants do all day? – Oliver, aged almost three, Kent, England

It is easy to think that the daily life of a plant is a simple one. They seem to just stand there and sunbathe. However, plants are very busy all the time doing many things. This activity is aimed at surviving the day and planning for the future.

Plants need food to survive. Being rooted in the ground means that they can’t move around to find food, so they must make their own.

They do this by taking water from the soil in through their roots and a molecule in the air, carbon dioxide, into their leaves. They then use the energy from sunlight which they absorb into their leaves to combine the water and carbon dioxide to make complex sugar molecules – food.

This process, called photosynthesis, is one of the most amazing chemical reactions on the planet.

Curious Kids is a series by The Conversation that gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.com and make sure you include the asker’s first name, age and town or city. We won’t be able to answer every question, but we’ll do our very best.

The plant then does one of two things with these sugar molecules. It can use them in respiration. This is a process that releases the energy of the sugar molecules to allow the plant to do its daily activities. It can also convert the sugar molecules into other more complex chemicals to build other plant parts, such as new leaves or flowers.

However, the chemicals that are used to make up plant parts need more than just the input of sunlight, water and carbon dioxide. They also need additional chemicals that they take from the soil. It is the same as humans needing a healthy diet.

So, the plant spends all day mining the soil for useful chemicals such as nitrates, phosphates and various metals. These must then be moved to the part of the plant where they are needed.

Measuring light

Every day, plants must measure the amount of daylight they are getting. In particular, they need to know whether the hours of daylight are getting less or more from one day to the next. Measuring this change allows the plant to recognise what time of year it is. If daylight is increasing, then it knows that it is spring and time to start producing flowers.

If daylight is getting less then the plant knows that winter is coming. It can put food into storage ready for next spring’s growth. For example, daffodils produce bulbs, and the potato plant makes tubers – which are the potatoes that we eat.

It can also get rid of things it will not need in the winter. Oak trees do not use leaves to make food during the winter, as there isn’t enough light. So, the leaves fall off its branches and grow again in spring.

While a plant is always keeping track of how much of the 24-hour period is daylight, a term scientists call light quantity, it also monitors any changes in light quality.

This is the type of light falling on the plant. It might be full sunlight, or it might be light that is filtered through the leaves of other plants. If the plant is not getting the right light quality, it means it is being shaded by other plants. It must either start growing taller to find the full sun again, or produce larger leaves to gather in more light.

Staying healthy

The plant also monitors its own health. If a plant is being eaten by insects, it can produce a set of chemicals to make its leaves less tasty.

We also know that plants that have detected they are being eaten can release chemicals into the air to warn its neighbours, and let them know that they should start making their leaves less tasty.

The same applies if fungal disease strikes the plant. The plant produces chemicals to attack the fungus and seals off parts of the plant that are damaged too much to be repaired.

So, every day, plants are making food, extracting minerals so they can grow, working out what season it is and whether they are getting enough light, and protecting themselves from animals that want to eat them – as well as warning their neighbours. It makes for a busy day, although one that is largely invisible to humans.

Paul Ashton, Head of Biology, Edge Hill University

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

How does our brain send signals to our body? – Aarav, aged nine, Mumbai, India.

For hundreds of years, scientists have tried to understand the human brain – known as the most complex organ in the universe.

The average human brain contains about 86 billion nerve cells, called neurons. These are the building blocks of your brain. Neurons communicate with each other by sending chemical and electrical signals.

Each neuron is connected with other neurons across tiny junctions called “synapses”. Impulses rush along tiny fibres, like electrical wires, from one neuron to the next.

Every time you recognise a familiar face, hear a voice, learn something new or read a word like this, millions of neurons are communicating with each other through hundreds of millions of synapses.

Curious Kids is a series by The Conversation, which gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.com. We won’t be able to answer every question, but we’ll do our very best.

Making sense

The brain is the body’s control centre: it sends messages to your body through a network of nerves called “the nervous system”, which controls your muscles, so that you can walk, run and move around.

The nervous system extends through your body from your spinal cord, which runs from your brain down your backbone, like the branches of a tree.

The brain is also in charge of the way you experience the world around you. Imagine you’re walking in a forest. The light bouncing off the trees enters your open eyes; the chirping sounds of the birds reach your ears; and the damp smell of the forest soil wafts up your nose.

The nerve cells in your eyes, ears and nose detect these sensations, and send signals to different parts of your brain, which turn them into what you see, hear and smell – all in a matter of milliseconds.

Sending signals

As well as sending electrical signals through the nervous system, the brain also uses chemical signals to control processes in the body.

Have you ever wondered why you feel sleepy? When the sun goes down, a part of your brain called the pineal gland produces a hormone called melatonin, which makes you feel tired.

Melatonin is produced a few hours later in teenagers than it is in adults and children. This makes teenagers want to go to bed and wake up later than adults and children.

Teenagers are not lazy: it’s all to do with how the brain sends signals to the body.

A sense of self

As well as allowing us to move around and understand what’s going on in the world, the brain gives us a sense of who we are – a “sense of self”, that’s different to other people.

Scientists don’t quite yet understand how the brain creates each person’s sense of self. But research has shown that when people think they are being watched by others, certain parts of their brains are busy. This part – called the “medial prefrontal cortex” – is what makes you feel self-conscious.

The human brain, with its billions of neurons working together, is sending signals to your body to determine how you feel, from one moment to the next.

The brain is always trying to find ways to explain the sensations that we feel in our body. And the same sensation can have different meanings in different contexts. Here’s an example: when you see a delicious piece of cake and your stomach churns, your brain might send signals to your body that you’re hungry and excited.

But if you’re about to have a test at school, your brain may give a different meaning to that churning stomach and create feelings of fear or anxiety.

The experiences you have become part of how your brain makes sense of what is happening to you. This means that people have more control over their emotions than they might think, because the brain can learn how to respond to experiences differently. As author Wayne Dyer said: “If you change the way you look at things, the things you look at change.”

From perceiving the world through the five senses, to creating our sense of self, uncovering how the human brain sends signals to our body is one of the biggest mysteries in science.

Children can have their own questions answered by experts – just send them in to Curious Kids, along with the child’s first name, age and town or city. You can:

• email curiouskids@theconversation.com
• tweet us @ConversationUK with #curiouskids
• DM us on Instagram @theconversationdotcom

Here are some more Curious Kids articles, written by academic experts:

• How can we see what we are imagining but still see what’s in front of us? – Malala Yousafzai class, Globe Primary School, London, UK.

• Why is the sea salty? – Torben, aged nine, Sussex, UK.

• Why do I have boogies and why does my nose keep replicating them? – Duncan, aged seven, Sydney, Australia.

Georgia Chronaki, Senior Lecturer in Developmental Neuroscience, University of Lancashire

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

This is an article from Curious Kids, a series for children of all ages. The Conversation is asking young people to send in questions they’d like an expert to answer. All questions are welcome: find out how to enter at the bottom.

How does our heart beat? – Aarav, age nine, Mumbai, India

Aarav – that’s an excellent question and one that matters to every single person on the planet!

The heart is a muscle, and all the muscles in the body work to move things around. Some muscles move our eyes as we read this page, others help us pick things up with our hands. These muscles are “voluntary”, which means you can control them. But other muscles in the body are “involuntary”, which means you can’t control them.

The heart is made of a special involuntary muscle called cardiac muscle, and this muscle is made up of cells called cardiomyocytes (which literally means “heart muscle cells” in Latin). You can’t control the heart muscle or its cells: they respond to the things our body needs, such as oxygen in our leg muscles as we move, or getting rid of our waste carbon dioxide by breathing out.

The heart has a special patch of cells called “pacemaker” cells, which are different to all the other muscles cells of the heart when you look at them with a microscope. These cells set the rhythm that the rest of the heart beats to, and they are located in the wall of the right atrium, which is the top right chamber of the heart.

The cells create an electrical impulse – like a small electric shock – that shoots out through special paths across the heart, to make sure all the other muscle cells contract in a wave pattern, to pump blood out of the heart, to the lungs and around the body.

This wave is caused by movement of tiny molecules that move from inside and outside the cells. These molecules come from the foods we eat and are used to keep us functioning, which is why it’s important to eat enough fruit and vegetables, and foods containing calcium.

Some people have problems with their pacemaker cells, so the electrical impulse doesn’t travel all the way through their heart, and their heart doesn’t contract properly. These people can have an operation to put a tiny machine in to control their heart rate – this is called a “pacemaker”, and it takes over from the pacemaker cells.

The heart doesn’t always beat at the same rhythm. Our heart responds to nervous signals sent from the brain, or to chemicals that the body produces in response to things it sees, hears or smells.

If your sibling dressed up in a scary costume to give you a fright, your eyes would see this, and chemical and electrical messages in the brain would send impulses to the heart, to cause it to beat faster. This would deliver more blood and oxygen to the cells of the arms and legs, so you could run away.

And when you are at home on a Saturday night, relaxing and watching your favourite TV show, the opposite thing happens: the heart doesn’t have to work as hard and so it relaxes and returns to its resting speed, with most blood going to the gut rather than the limbs, again caused by chemical and electrical messages.

The heart beats around 60 to 70 times each minute, and when we exercise really hard, it can beat as many as 220 times per minute. Children’s hearts can beat faster than adults’, especially when you’re exercising hard.

If you want to figure out the most beats your heart can do in a minute, the calculation is 220 minus your age – so in your case, 220 minus nine equals 211 beats per minute, when you’re exercising as hard as possible. For someone of my age, it’s around 190 beats per minute.

To feel how hard your heart works, try clenching and relaxing your fist 60 times in a minute. Hard work, right? And remember, your heart beats 60 times per minute, 60 minutes an hour, 24 hours a day and 365 days per year. That’s 31,536,000 beats every year – if all we did was just sit still! Luckily, your heart does get to have a little rest, in between every beat.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:

* Email your question to curiouskids@theconversation.com
* Tell us on Twitter by tagging @ConversationUK with the hashtag #curiouskids, or
* Message us on Facebook.

Please tell us your name, age and which town or city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question, but we will do our best.

More Curious Kids articles, written by academic experts:

• How do birds see where they’re going? – Thomas and Luke, age six, Sussex, UK

• What sea creature can attack and win over a blue whale? – Drake, age seven, Sydney, Australia

• Do butterflies remember being caterpillars? – Evan, age 5, Bristol, UK

Adam Taylor, Director of the Clinical Anatomy Learning Centre and Senior Lecturer, Lancaster University

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