This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

Is it true that with seahorses, males give birth? - JJ, age 9, Brisbane.

Great question! It sounds crazy, but it is true.

Seahorses and their close relatives the pipefish and the seadragons are very unusual, because it is the males that get pregnant and give birth to the babies. Instead of growing the baby seahorses inside their belly in a uterus, like human mums do, the seahorse dads will carry the babies in a pouch, a bit like a kangaroo’s pouch.

To produce babies, seahorses have to mate first. Seahorse mating is really beautiful. Males and females dance around one another and flutter their fins, and they may dance together over several days before they actually mate.

When they’ve decided they like each other, the seahorse females swim towards the surface of the water, and the males follow. The females then put their bright orange eggs into the pouch of the males through the hole at the top of the pouch. Once the eggs are safely inside, the males will add their sperm and shut the opening. The eggs are fertilised by the sperm, and then start developing into baby seahorses.

With that, the job of the seahorse mum is done! She swims off, and leaves the father to take care of the growing babies. Inside the pouch, the babies grow eyes, tiny snouts, and little tails. It takes about 20 days for the babies to develop, safely tucked away from other animals that might want to eat them.

It’s tough being a baby seahorse

When male seahorses give birth, it is very dramatic. You can watch a cool video of seahorse birth here:

The male will open the hole in his brood pouch, and violently jerk around to squeeze all of the babies out. They shoot out very quickly, and it looks spectacular. In fact, some species of seahorse can give birth to more than 1,000 babies at once!

After he has given birth, the seahorse dad does nothing more for his babies. They must look after themselves and hide from predators, as they have no parents to protect them. The seahorse father does not eat until several hours after he has given birth. However, if the babies are still hanging around him after that, they may become a tasty meal. That’s right, males sometimes eat their own babies.

It’s tough being a baby seahorse. Of the hundreds of babies that the male gives birth to, only one or two will survive to become adults and have babies of their own.

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

* Email your question to curiouskids@theconversation.edu.au
* Tell us on Twitter by tagging @ConversationEDU with the hashtag #curiouskids, or
* Tell us on Facebook

Please tell us your name, age, and which 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.

Camilla Whittington, Research Fellow / Lecturer, University of Sydney

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

This is the first piece in Curious Kids, a new series aimed at children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky! Email your question to curiouskids@theconversation.edu.au

Where does money come from? – Millie, aged 5, Sydney.

If you look inside your parents’ wallets, you’ll see some brightly coloured plastic sheets and some little plastic cards. These plastic notes and cards are “money”, which your parents use to buy food, clothes, and beautiful toys.

When I was a child, I used to read The Adventures of Pinocchio. Pinocchio is a puppet who became a child. He believed that money grew on trees. It took him a bit of time to understand that this isn’t true.

Money doesn’t grow on trees. Your parents have to work in a job to get it.

The plastic notes come from a place called the Federal Reserve Bank of Australia. You can call it “the RBA” for short.

The RBA is in Sydney. The people who work there operate a machine that prints and cuts the yellow, red, purple and blue plastic notes that you have seen in your parents’ wallets.

The good people at the RBA can print pretty much as many of these notes as they want. But they know that if they print too many of these notes, then something not so nice will happen. This not so nice thing is called “inflation”. Let me explain what that means.

When there are too many notes going around, people start to spend more and more money. Because there is so much money going around, the people in shops start charging more for things like food and clothes and beautiful toys. Everything starts to get more expensive. That’s inflation.

So, when you hear your parents saying that “life is too expensive”, you can blame it on inflation.

We haven’t always had money like the money you see today. A few thousand years ago, people wouldn’t buy things, they would swap. For example, you could swap some vegetables from your garden with your friend to get some ham, for example.

That worked for a while, but humans eventually decided it was easier to make small notes and coins than to go around finding shells, vegetables or salt to trade, and that’s how the money system was born.

The plastic cards inside your parents’ wallet are also money. The coloured plastic notes are beautiful, but you can lose them, and it’s hard to keep them all in your wallet if you need a lot of them to buy lots of things.

So, instead of going around with a lot of notes, people put their notes in a place called a “bank”. The bank keeps the notes safe for you and gives you a plastic card in return.

When your parents need to get some notes from the bank, they use this plastic card. They put the card into a machine, the machine reads the card and knows that the owner of that card has notes in the bank. Then your parents tell the machine how many of their notes they want back and the machine gives them the notes.

But there is one more surprise: these plastic cards can be used to buy things today and pay next month!

Your parents do not even need to go to the store with paper money. They can go to the store with their plastic card and show it to the shop owner. The shop owner will tell the bank that they have purchased some things. Next month, the bank will ask your parents to pay for those things using their paper notes.

That’s why the plastic cards are basically the same as plastic money.

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

* Email your question to curiouskids@theconversation.edu.au
* Tell us on Twitter by tagging @ConversationEDU with the hashtag #curiouskids, or
* Tell us on Facebook

Please tell us your name and age (and, if you want to, which city you live in). Send as many questions as you like! We won’t be able to answer every question but we will do our best.

Fabrizio Carmignani, Professor, Griffith Business School, Griffith University

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

Curious Kids is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

How can penguins and polar bears stay warm in the freezing cold waters of Antarctica? - Riley, age 8, Clarksville, Tennessee USA.

Thanks for your question, Riley. The first thing I should probably say is that while a lot of people think polar bears and penguins live together, in fact they live at opposite ends of the Earth. Polar bears live in the northern hemisphere and penguins live in the southern hemisphere.

I’m a penguin researcher so I’m going to explain here how penguins can stay warm in Antarctica.

There are four species of penguins that live in Antarctica: emperors, gentoos, chinstraps, and Adélies.

All these penguins have special adaptations to keep them warm, but emperor penguins might be the most extreme birds in the world. These amazing animals dive up to 500 metres below the surface of the ocean to catch their prey, withstanding crushing pressures and water temperatures as low as -1.8°C.

But their most incredible feat takes place not in the ocean, but on the sea ice above it.

Surviving on the ice

Emperor penguin chicks must hatch in spring so they can be ready to go to sea during the warmest time of year. For this timing to work, emperors gather in large groups on sea ice to begin their breeding in April, lay their eggs in May, and then the males protect the eggs for four months throughout the harsh Antarctic winter.

It’s dark, windy, and cold. Air temperatures regularly fall below -30°C, and occasionally drop to -60°C during blizzards. These temperatures could easily kill a human in minutes. But emperor penguins endure it, to give their chicks the best start in life.

A body ‘too big’ for its head

Emperor penguins have four layers of overlapping feathers that provide excellent protection from wind, and thick layers of fat that trap heat inside the body.

Have you ever noticed that an emperor penguin’s body looks too big for its head and feet? This is another adaptation to keep them warm.

The first place that you feel cold is your hands and feet, because these parts are furthest from your main body and so lose heat easily.

This is the same for penguins, so they have evolved a small beak, small flippers, and small legs and feet, so that less heat can be lost from these areas.

They also have specially arranged veins and arteries in these body parts, which helps recycle their body warmth. For example, in their nasal passages (inside their noses), blood vessels are arranged so they can regain most of the heat that would be lost by breathing.

Huddle time

Male emperor penguins gather close together in big groups called “huddles” to minimise how much of their body surface is exposed to cold air while they are incubating eggs.

This can cut heat loss in half and keep penguins’ core temperature at about 37°C even while the air outside the huddle is below -30°C.

The biggest huddles ever observed had about 5,000 penguins! Penguins take turns to be on the outer edge of the huddle, protecting those on the inside from the wind.

Incredibly, during this four-month period of egg incubation the male penguins don’t eat anything and must rely on their existing fat stores. This long fast would be impossible unless they worked together.

Changing habitats

Emperor penguins are uniquely adapted to their Antarctic home. As temperatures rise and sea ice disappears, emperors will face new challenges. If it becomes too warm they will get heat-stressed, and if the sea ice vanishes they will have nowhere to breed. Sadly, these incredible animals may face extinction in the future. The best thing we can do for emperor penguins is to take action on climate change now.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.

Jane Younger, Research Fellow, University of Bath

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. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky! You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

How do remote controls work? – Ethan, 10, Sydney.

Thanks, Ethan. I was younger, I wondered the same. I was completely mesmerised with how a lump of plastic could possibly change channels on a TV without any physical connection.

Very early TV remote controls worked with wires. Then we created battery-powered remotes and we didn’t need the wires any more.

Now remotes are everywhere. In fact, the planet-watching Voyager spacecraft are controlled remotely and they are presently 20 billion kilometres away. It takes 20 hours for instructions to travel from Earth to the spacecraft but we can do it – using a remote.

A remote control has three things, what engineers would call a “communications channel”, a “procotol”, and an “interface”. I will explain what those words mean.

The communications channel

The communications channel is what connects the remote to the device you want to control (like a TV).

It could be light (such as infra-red light), sound or radio waves (sometimes called electromagnetic waves). The human eye cannot see infra-red light or radio waves.

TVs tend to use infrared light as it is low cost, easy to build, and suitable for a short distance like in a lounge room. However, it does require a direct “line of sight” so that the light beam is not blocked. How many times have you heard “get out of the way!” when someone is trying to change the channel?

Radio waves are usually used for long distance situations, or for outdoors, and can even travel through objects.

Many game consoles like the XBox and PlayStation use low power radio waves (like Bluetooth, which is a type of radio wave system). This is great for games as it does not need line of sight. It will still work even if you bounce around the room, or dive behind the couch with your controller.

Protocol

You can think of the protocol as the “language” the remote uses to communicate with the TV, XBox or whatever the device may be.

TVs, for instance, use a long list of “binary codes” (on and off, or one and zero bit sequences) that tell the TV what to do. Some codes tell the TV volume to go up, others tell it to go down, or change channel.

These patterns have been predetermined so that the TV will understand the remote. It can “speak” the language of the remote. The remote will package the message up in a little packet of data that the TV can understand.

Some remotes are able to send messages and receive them. For instance, a game console control will send commands to the console (eg “move the character forward”) and can receive them (for example, “make the controller rumble and vibrate”).

User interface

“User interface” is just a fancy way of saying how the remote looks and is used.

TV remotes just have a rather boring array of buttons. Some remotes have a screen and look like a mobile phone.

Pump up the volume

Say you want to turn up the volume on your TV. You press a button on the remote. The little microcontroller (which is just a tiny computer) in the remote wakes up, and reads which button you have pressed (“volume turned up, please”). It then creates a packet of data – a message – in a language the TV can understand.

It sends the message via an infrared light to the TV, assuming you aimed the remote correctly.

That message is then picked up by the infrared TV receiver, which decodes it (“ahh, he wants the volume turned up, ok.”). Then the small microcontroller (a tiny computer) in the TV makes the necessary changes to the volume.

All remotes all are designed to:

1. take your request
2. apply the protocol (translate it into a language the device can understand)
3. create a packet of data (a message) and
4. send the message via the communications channel to the device.

You then put these things together and you have a remote control.

Even the remote used to control the Voyager Spacecraft follows the same method. It’s no more complicated than controlling a TV, it just has more steps to it.

Thank you for this question, and I hope I have helped you understand the fascinating world of remote controls.

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

* Email your question to curiouskids@theconversation.edu.au
* Tell us on Twitter

Please tell us your name, age and which 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.

Andrew Maxwell, Senior Lecturer, University of Southern Queensland

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

Curious Kids is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

Why do bats sleep upside down? - Questions from Year 5 at Brandon Park Primary School, Victoria. The class has been studying animal adaptation.

Evolution allows animals to adapt to their environments by favouring those who have an advantage that helps them survive. If they survive long enough to have babies they pass that advantage onto their children through their genes. That process is what we call adaptation.

Animals have adapted to live in different environments and eat different foods, so they don’t have to compete with each other.

Around 530 million years ago, all animals lived in the ocean. They were rapidly evolving and adapting to live in different places to minimise competition.

Some animals have evolved to live at great depths, like the anglerfish. It has a bioluminescent light it uses to attract prey in the dark water. Other sea creatures evolved amazing camouflage skills, which helps them stay safe from predators.

Eventually, sea animals developed adaptations that allowed them to live on land. More adaptations occurred over millions of years, leading to the amazing and complex range of animals we have today.

Sometimes, two different animals will evolve to have a similar adaptation, even when they are not closely related. Flight is an excellent example.

The four flights

Flight has evolved four times: in insects, bats, birds and pterosaurs (the flying creatures from the time of dinosaurs).

These four groups don’t have a common ancestor who could fly. In fact, they all evolved to fly from ancestors who could not. This is what we call “convergent evolution”.

However, birds and bats have some major differences. Bats still have the five digits, or fingers, that their mammalian ancestors had (mammalian means they are mammals, which are animals who have a mammary gland, that produces milk to feed their babies; they also typically have hair or fur).

Birds, however, have lost the digits that their ancestors had. The bones in a bird wing have fused.

Hunt, but don’t be hunted

The bat ancestor (or pre-bat) lived in trees, hunting small insects as they moved along the bark. Since it’s much harder to run up a tree chasing an insect, the pre-bat would wait, facing downwards for prey to come up the tree trunk. That way they could easily run downwards if they saw something tasty.

They used their hands and mouth to grab the prey and hung from their back legs. This led to an adaptation in their claws which allowed their tendons to lock into place when they hang. That’s why bats can hang upside down without using muscles, and barely any energy. Gravity does all of the work for them.

Since it uses the least amount of energy, it’s the best way for a bat to sleep. But on the trunk of a tree, they are visible to predators who hunt during the day while bats are sleeping. Some bats moved to sleep under the horizontal branches, which provided protection.

As with all evolution, the adaptations that help a species to survive is the one that will persist. Most bats now sleep in protected areas and only a few species still sleep on tree trunks.

Make light work

To save energy while flying, you want to make yourself as light as possible. Birds have hollow processes in their bones but bats do not. One way in which bats evolved to save weight was to make their back leg bones shorter and thinner.

However, this means that the bats can no longer stand on their back legs. The pressure is too much for the small bones. As a result, they have lost the ability to run on their back legs as well.

The drop and fly theory

When you watch a bird take off from the ground, you will notice they need a run-up. In order to get off the ground, flying animals needs to achieve what scientists call “lift” to overcome gravity. Many big birds, and bats, do not have strong enough wing muscles to generate the lift required to take off from a standing position (like a helicopter can).

Bats cannot run so it would be almost impossible for them to take off from the ground. A major advantage to hanging upside down is that bats do not need to generate lift to begin flight. They just drop out of their bed, open their wings and off they go.

Did you know there are seven species of bats that do not sleep upside down? They sleep in curled-up leaves! Six of these species live in Central and South America, while the other one lives only in Madagascar.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au

Amy Edwards, Post Doctoral Researcher, La Trobe University

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