The curious link between smell and memory

Aquila Magazine for children, December 2015. 

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The curious link between smell and memory

Why is smell such a strong trigger for bringing back memories? And what happens in our brains when a memory comes flooding back?

Smells have a funny way of bringing back memories you hadn’t thought about in a long time – maybe even things you’d forgot all about. If you’re not sure what we mean, just go and take a whiff from a bottle of sunscreen. It may be winter right now, but it will bring you right back to the beach, or the park, or wherever you were the last time it was hot enough to need to put on suntan lotion. But even if it’s snowing outside, chances are the smell will trigger memories and feelings of summer, and they’ll come flooding into your head, far more intensely than they would by just talking about it.

memory1This little memory trick works with all sorts of scents we have an emotional connection to. Think about how the smell in the air changes when summer turns to autumn, and it can only mean one thing: school’s back. Or if you’re in a car or train on the way to the sea, and you can smell the saltwater long before you can see it. Many of the smells we experience in childhood will act as doorways to memories when we’re grow up, waiting to be rediscovered if we smell something just like it again. Say if your grandfather is a woodworker and you like spending time in his workshop, the smell of wood shavings will probably remind you of this for the rest of your life. Sometimes the special smell can be really subtle, like the smell inside a toy chest or a wall clock, meaning you may not even realise it has meaning to you. But one day in the future you could find yourself smelling it again, and the effect can be striking: suddenly you will be right back to the place, and maybe even the time, where you were the first time you experienced that smell.

But how is it possible for smells to do this?

Out of the five senses – smell, sight, touch, hearing, taste – neuroscientists have discovered that smell is the oldest. What they mean by this is that in the history of evolution, creatures were early to develop the ability to “smell” chemicals in the air and water around them. Because of this, we can say that even bacteria have a sense of smell. But while we’re good at describing how things look or taste, we’re actually pretty bad at describing how something smell. While we describe tastes as sour or sweet, we usually resort to comparing smells to something else – like fresh bread, a meadow, or dog poop. Or as you might say if a smell triggers a memory: “This cake smells like my grandma’s kitchen.”

Let’s take a look at how we process scents inside our brains. The part of the brain responsible for handling smells is called the olfactory bulb: it starts inside the nose before running up into the brain. The olfactory bulb has connections to two other parts of the brain: the amygdala, which deals with emotion, and the hippocampus, which is very important for creating memories. Most other senses don’t touch on these areas as they travel into the brain, meaning they’re not as likely to bring back memories of the same intensity. Maybe that’s why hearing the word “rose” isn’t as effective for remembering as smelling a rose?

memory2Another unique thing about smell is that it moves very quickly to reach deep inside the brain, unlike the other senses which travel along a less direct pathway. Take vision – it starts in the eyes of course, before moving on to a relay station inside the brain called the thalamus, and only then moving further into the brain. Hearing does the same thing. Smell, however, skips the extra step and goes straight for the olfactory bulb. We don’t quite know why this happens, but having a straighter route with fewer pit stops may account for some of the reason that smells can hit us so hard. Researchers have actually discovered that using words to describe things can make the memories less intense, because when we talk about something that’s happened, we start to think of it like a story that we’re shaping, instead of just experiencing raw emotions.

But why can smells bring back memories so faint we thought we’d lost them? We’re not completely sure why this happens, but there’s a few clues in the brain’s memory centre, the hippocampus. Here’s one way to think about it: if a person were to suffer brain damage that affected their hippocampus, they would struggle to remember things after they had happened. But they could still learn new things. So for example, if that person with brain damage were to learn how to ride a bicycle, they wouldn’t remember learning it – but if given a bike, they would be able to ride it. This is because the memory of learning, and the ability to ride a bike, is saved in different places in the brain. That makes it possible to forget the smell of fresh snow at Christmas, but smelling it again years later could still trigger the experience of snow, and we’d feel something. So even if we have lost the memory, the experience could still be kept safe inside our brains, waiting for the right smell to bring it back.

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Big Data: Finding the patterns in the noise

Aquila Magazine (kids 8-12) – May 2015

Scan 3Big Data: Finding the patterns in the noise

We create over 2.5 quintillion bytes of data every day – that’s a lot of text, pictures, video and social media messages. Powerful computers can analyse this “Big Data” and find new patterns, and maybe even hints about the future.

How much data exists in the world? Nobody really knows, but we are creating more and more every day. The numbers are so big they hardly make sense: over 2.5 quintillion bytes of data is added every day, according to IBM – a quintillion is 1 followed by 18 zeros. There’s a name for all this – we call it “Big Data”.

So what do we mean when we say “data”? It’s everything that comes through a computer, yes, but it includes not only all the text, but lots of other things too like voice recordings and video. So when we look at data we’re not just counting text stored by businesses, newspapers and libraries, but also social media posts, online shopping orders, internet chats, and all those videos of cats jumping into boxes.

Today’s powerful computers can be used to analyse all this data and keep track of it, even as it’s growing at an ever-increasing pace. Over 90% of all data was created in the last few years alone, as technology has become more accessible and easy to use for a lot more people. The ideal outcome of collecting all this information is that we will be able to see new patterns, which may even be able to tell us about the future. One example is Google Flu Trends, which essentially looked at who was searching the web for flu symptoms, where those people lived, and used that data to predict where the next flu outbreak was going to be.

Big Data analysis is not perfect – after all, not everyone who looks up symptoms on the internet is sick. But as we collect more types of data we should be able to be more specific in our predictions. For example, futuristic refrigerators can email you shopping lists when you’ve run out of food, and a town will soon be able to monitor which parking lots are full and lead visitors to the nearest vacant spot by sending them a text message. All this is data too, and if these details, and millions of others, are put together, we may be able to see some surprising connections.

Farmers are already able to use Big Data analysis to work out which fields need what kind of fertiliser, and there are great possibilities in the field of medicine. For instance, the Howard Hughes Medical Institute in the US is using Big Data to analyse scans of the brain: “When you record information from the brain, you don’t know the best way to get the information that you need out of it. Every data set is different,” said Mischa Ahrens, one of the researchers. Scanning the vastly complex brain creates so much information it can be overwhelming, but Big Data analysis has made it possible for researchers to test out ideas faster. This will hopefully cut down the time it takes to come up with new treatments for illnesses.

Big Data is being used for strictly fun purposes too: sports fans who like to watch the replays and study the match statistics have increasingly more data to play with. During the Wimbledon Championship, a service called the Slamtracker gives tennis buffs access to data collected from eight years of tournaments. This means people can look up their favourite players’ performance statistics and playing styles, and even get victory predictions based on the backgrounds of their opponents.

While there’s no doubly the opportunities are vast, one question remains: who owns Big Data? This is especially important as we give away more and more information about ourselves on the internet, often in exchange for using services like email or social media without having to pay. Companies like Facebook and Twitter assure us information belongs to users, but the companies are still using this information to sell advertising. And what about the data collected by the phone company? Even if they’re not listening to what we are saying, the time, duration and location of a call is data too. Right now, companies are often using data about people anonymously, meaning they look at how many people did something and where they were, but the names are kept out of it.
As we continue to gather data, Big Data analysts will be able to glean more and more insights that will hopefully help us create products and services to make life better. A deli can use Big Data to work out which sandwiches sell best in what weather, for example, and make sure they don’t run out. Airlines can crunch the numbers to come up with a quicker way to board airplanes, and towns can use traffic flow analysis to prevent queues.

It’s exciting to think about what we can do with our new power of Big Data analysis, and this is only the beginning. “Big Data marks the start of a major transformation,” said authors Kenneth Cukier and Viktor Mayer-Schonberger in their book ‘Big Data’. “Just as the telescope enabled us to comprehend the universe and the microscope allowed us to understand germs, the new techniques for collecting and analysing huge bodies of data will help us make sense of our world in ways we are just starting to appreciate.”

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Who was Marie Antoinette?

Aquila Magazine for kids, March 2015.

ScanWho was Marie Antoinette?
Marie Antoinette was executed in the French Revolution. But was the last Queen of France really as out of touch as people thought? And did she really say that people who couldn’t afford bread should just eat cake instead?

Marie Antoinette was born in 1755 in Vienna, as an Archduchess of the Austrian Empire. Baptised Maria Antonia Josepha Johanna, the girl was described as “small but completely healthy”, and had a happy childhood with her 15 brothers and sisters. Considering what was customary for a royal family at the time, Marie Antoinette had a pretty relaxed upbringing. The children were allowed privacy from the rest of the court, so they could dress more casually, learn from their teachers, and play in the gardens, often with regular kids.

In those days, royal marriages were tools for forging alliances between countries. For this reason, Marie Antoinette’s mother, the Duchess, decided her daughter should marry the boy set to become the next king of France. Marie Antoinette was only 15 when she was married to 16-year-old Louis, and the teenagers had never met when they were married in a ceremony where they weren’t even present. Before she left for France to start her new life, Marie Antoinette’s mother told her daughter to never forget she was Austrian, even when she was the Queen of France. But the French had other ideas, as young Marie Antoinette was made to get rid of all her Austrian belongings, even her clothes and her dog, replacing everything with French things.

Life for Marie Antoinette wasn’t easy once she arrived at the Palace of Versailles. As the Queen, she had to deal with everyone at court keeping an eye on her, gossiping about what she got up to. Her marriage to Louis was difficult, partially because the couple didn’t have children for eight years, something that caused a lot of speculation around the court. They eventually had four kids: Marie Thérèse, Louis Joseph, Louis Charles, and Marie Sophie, who the Queen was very close to as she took care of their upbringing and education herself.

But for all those years before her kids were born, Marie Antoinette had few royal duties, so she didn’t actually have all that much to do. As a young girl far from her family, the Queen spent much of her time socialising, and buying fancy clothes and jewellery. She liked to ride horses, but also enjoyed gambling on cards and horse races. At a time when France was struggling financially, stories about the Queen spending a lot of money were spread around, and criticised in the newspapers. The Queen and her friends, it was written at the time, “loved pleasure and hated restraint; laughed at everything, even the tattle about their own reputations; and recognised no law save the necessity of spending their lives in gaiety”.

As the first lady of the court, Marie Antoinette was supposed to set standards for fashion, so she’d buy a lot of new dresses, shoes, hats, perfume and makeup, sometimes even going into debt to pay for everything. At a time when many people were poor or starving, it looked bad that a woman who had so many luxuries would play dress-up with her friends, running around on a model farm dressed up as milkmaids and shepherdesses. This was considered insulting to real farmers, even though Marie Antoinette was probably just trying to fill her time, recreating the playful games of her childhood in Vienna.

While she did spend a lot of money, Marie Antoinette was certainly not to blame for all of France’s financial problems, as many people liked to say. The country was in debt mainly because of its involvement in the American Revolution, which cost far, far more than the Queen’s extravagant wardrobe. The royals’ money splurging did give the impression of being out of touch, but the social unrest in France was more based in the fact that ordinary people had to pay high taxes, while the richest people who owned the most land did not.

In the winter of 1788, the rising prices of bread led to a crisis in France, and Marie Antoinette was rumoured to have responded to the problem by saying: “Let them eat cake!” This wasn’t actually true, as Marie Antoinette gave a lot of money to charity and would have known better than to say something so silly. But people wanted someone to be angry with, and it was easy to blame the Queen had a reputation of spending too much money and not caring much about the people.

Once the French Revolution started in July 1789, the royal family quickly realised they were in danger and left the Palace of Versailles for Paris. Marie Antoinette tried to stay out of things and focus on her children, still hoping her son would become king of France one day. But as the revolution roared on, the monarchy was declared over and the royal family stripped of their titles. To make sure the King could never reclaim his power, the revolutionaries executed King Louis for treason, and as the Queen, Marie Antoinette suffered the same fate nine months later. She was 39 years old when she was executed by guillotine, after a rushed trial. Somehow, Marie Antoinette managed to get hold of a pristine white dress and bonnet for the occasion, determined to make a final impression of defiance. Her last words was to her executioner, after she accidentally stepped on his foot: “Pardon me Sir, I didn’t mean to do it.”

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Where the internet lives

Aquila Magazine (for children aged 7-12) – June 2014. Original article.

upintheair-0614uWhere does the internet live?
What is the internet? We could compare it to a giant library, except we can get to any page in any book immediately. Or we could compare it to a post office, except letters are delivered right away. It’s a shop too – we can buy pretty much anything we want from almost anywhere in the world, and it will be delivered to our homes a couple of days later. And lately the internet has been turning into a great big playground, where we can talk to each other, play games, look at pictures together, and learn about life in other countries by talking to people who live there.

We can see all these things on our computer screens, but that’s just a window into the vast global network that makes up the internet. So where exactly is the internet? What does the internet actually look like? If you have seen the insides of a computer, or even a simpler electronic device put together with lots of wires and chips, this will give you an idea what the internet looks like. Except, of course, the internet is a lot bigger and much more complicated.

The electronic library
Just like we have bookshelves for storing books, all the websites with all the photos, text and videos need to be stored somewhere too. The internet is stored in massive stacks of electronic memory boards and magnetic discs, located in big buildings called datacentres. These are placed all over the world and look pretty boring: just rows and rows of cupboards, linked by millions of wires. Websites have to pay rent for the space they use in a datacentre, and the more space they need the more it costs. This is because datacentres run on electricity, they generate a lot of heat so they need cooling down, and they need to be kept secure so no one can break in and steal the data. Avoiding “blackouts”, which would mean people can’t get to websites, is incredibly important for datacentres, so they need backup solutions in the event of equipment failure or power cuts.

The data that makes up the internet is led away from the datacentres by cables that go into the ground, and we can access these in our houses by hooking up them like we do with electricity and water. The cables that transport the internet are made from fibre-optics, which mean they work by light pulsing through bundles of many tiny cables, each the width of a human hair. This is faster than metal wires over longer distances, which is important when considering that internet cables also run between continents, buried at the bottom of the ocean.

Transport by light
Today’s fibre-optic cables are a big improvement from the first transatlantic cable, which was a copper wire laid in 1858. The first message was sent from the US president to Britain’s Queen Victoria, and it took 17 hours to come through. This was pretty good at the time, considering the alternative was sending a letter by boat. The US president called it “a triumph more glorious, because far more useful to mankind, than was ever won by conqueror on the field of battle”. A lot has improved since then, as data from a website in America or China now travels in the blink of an eye to load on a computer here in Britain.

It’s even more impressive when we consider that the internet is often used without actually plugging a cable into the network. When we look at websites on mobile phones, the data is coming in wirelessly through the phone network. Wireless internet, or WiFi, is popular in homes as well as cafes, as it lets us connect many mobiles, laptops and tablet computers to the network without cables. WiFi works by taking a signal that comes in through a cable, and converting it to a radio signal for devices can tap into. On a big scale, a similar method lets us use internet satellites to get internet connections out to remote areas, or to ships at sea.

Over shorter distances, Bluetooth technology lets us send data without a cable by creating a mini network between two devices, so we can do things like sending a photo from a computer to a printer. More and more devices are being networked so we can control them from a distance, such as TVs, cars and refrigerators. It’s already possible to turn on the heating before we get home by sending a signal via the internet, because heaters are being installed with networked control panels.

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WWW: A common language
The internet was first invented in the 1960s by the US Defence Department, who called it ARPAnet. It became popular among universities who found it useful to be able to share data with other schools. Still, it wasn’t until 1991 that the internet as we know it now was born, when Englishman Tim Berners-Lee invented the World Wide Web. WWW became the common language for the whole internet, making it possible for anyone to access any page. Instead of just being for researchers or governments, Tim Berners-Lee wanted the internet to be a social medium, a place where everyone can share ideas with other people and work together.

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Thor Heyerdahl

In Aquila Children’s Magazine (ages 7-12), February 2014.

scandinavia-feb14uThe adventures of Thor Heyerdahl
Norwegian explorer Thor Heyerdahl crossed the open ocean on wooden rafts, risking his life to prove that people in pre-historic times could have travelled the world.

When a young, unknown researcher named Thor Heyerdahl claimed people from South America had travelled to the islands in the Pacific Ocean, no one took him seriously. Most scientists were certain: the people who live on these islands, known as Polynesia, had come from Asia. This was because pre-historic South Americans didn’t have any boats which could have survived the long and dangerous journey.

Heyerdahl quickly understood there was only way to prove his theory: travel across the ocean himself. A crazy idea for sure, but Heyerdahl had a raft built, using the same materials and methods as the pre-historic South Americans would have used. With a crew of seven, Heyerdahl set out from Peru in April 1947, letting the sea currents and wind take them where it wanted. The Kon-Tiki raft travelled 7,964 kilometres before reaching Polynesia, 101 days later. Heyerdahl had proved he was right: pre-historic South Americans could have crossed the Pacific Ocean.

The young explorer
Thor Heyerdahl was born in Southern Norway in 1914, in the town of Larvik. It was his mother, Alison, who inspired him to become a researcher. She was a chairwoman of the city’s museum association, and a supporter of Charles Darwin’s theory of evolution. Thor created a small museum in the office of his father, a master brewer also called Thor. Young Thor decided to become an explorer when he was eight, and went to the University of Oslo to study biology and geography. There Thor met a collector who had travelled in Polynesia, a friendship which inspired Thor’s interest in the region. Soon after, he went to the island of Fatu-Hiva and lived there for one year.

Heyerdahl wanted to discover how Polynesia originally became filled with plants, trees and animals. He realised the winds and ocean currents were constantly coming from South America, and that this had consequences for plant life. But it was only when he found the same types of statutes on the islands as previously found in South America, that Heyerdahl started wondering: maybe the winds and currents brought more than just plants from South America to Polynesia? Maybe they brought people too?

Kon-Tiki
This was when Heyerdahl decided to prove this theory by setting sail on the Kon-Tiki. In the documentary he made about the trip he talks about how people doubted whether the crew would survive. After all, no one could save them once they headed out into the open sea on their simple raft, made from nine balsa tree logs with a small hut on top. “On calm days, we would float like a cork,” said Heyerdahl. “On smooth days, it felt like utopia.” But not every day was calm. Lorita, the seasick parrot who had come along from Peru, was lost in a storm. Swimming was dangerous because of the strong currents, not to mention the sharks which frequently followed the raft. The whales were dangerous too, as they sometimes topple small boats at sea. Heyerdahl admitted there were times he feared for his life on the Kon-Tiki, as he had been afraid of water as a child and really learned how to swim.

Ra and Tigris
Heyerdahl became famous after the Kon-Tiki mission. While most scientists still disagreed with his theory that South Americans had travelled to Polynesia, at least it was clear it was possible. Heyerdahl was a big believer in the diffusionist theory: the idea that pre-historic civilisations had been in contact with each other. This could explain why groups who lived very far apart, like the Egyptians in Africa and the Mayans in South America, both built pyramids. But most scientists, both during Heyerdahl’s time and now, are separatists: they believe these similarities are coincidental, probably occurring because people all over the world have a lot in common.

Heyerdahl’s next sea voyage came in 1969, after he found pictures of reed boats during his archeological digs on Easter Island in Polynesia. Reed boats were also common among Mediterranean civilisations, meaning people could have travelled from there to South America, and then to Polynesia. Heyerdahl decided again to prove the skeptics wrong, and built a boat out of reeds and set sail from Morocco. Ra 1 had to be abandoned after 5,000 kilometres, but Heyerdahl was undeterred. Ten months later he tried again with Ra 2, which successfully reached South America.

Heyerdahl’s largest reed boat was built in 1977, this time with the ability to navigate instead of just drifting. The Tigris set out to prove it had been possible for people in the ancient civilisations of Mesopotamia, Egypt, and the Indus Valley to be in contact with each other. After five months at sea, the Tigris ended its voyage by the Red Sea, where Heyerdahl burned the proud ship in protest of the wars happening in the surrounding countries.

The biggest adventure
People describe Heyerdahl as a charismatic man with massive amounts of energy. But in video interviews he comes across as modest, almost shy, using formal language and always determined to make us understand: this is about science. For Heyerdahl, his voyages were also a message for people to work together. His crews on Ra and Tigris were all from different countries sailing under the United Nations flag, proving that people born to different places, habits and religions can work together. “Each of us were depending on the others’ friendship and help to survive. We knew if one of us was unwell, it would affect us all. That we all got along so well, that was the greatest part,” said Heyerdah, in an interview on Norwegian TV. “When you get to the bottom of it, to the big questions of life and death, people are so similar. We are all slices of the same loaf.”

During the Ra voyages, Heyerdahl became concerned with pollution of the world’s waters, as the crew found hardened clumps of tar floating in the water nearly every day of the 57-day-long trip. Heyerdahl’s reports were an important wake-up call for the international community about the dangers of pollution. “We seem to believe the ocean is endless. We use it like a sewer,” said Heyerdahl. Remaining a vocal advocate for the environment for the rest of his life, Heyerdahl was also a tireless supporter of international collaboration: “Borders – I have never seen one. But I have heard they exist in the minds of some people.”

Heyerdahl died in 2002 when he was 87 years old, living with his third wife Jacqueline in Italy. He had five children from two previous marriages: Bjørn, Thor Junior, Annette, Marian and Helene Elisabeth. While the theory of contact between pre-historic societies has now largely fallen out of favour, Heyerdahl continued his work until his death, convinced he was right. We may never know for sure, but last year research from the University of Oslo provided clues. Blood samples from the current inhabitants of Polynesia show they are mostly descended from Asia, but some of them have South American genes too. So it seems Heyerdahl was at least a little bit right.

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Technology in times of crisis

In Aquila Children’s Magazine (ages 7-12), March 2014.

aquila2Technology in times of crisis
The best technology is often the one that’s the simplest, cheapest and easiest to use. Think about it: you don’t want it breaking, you don’t want to spend ages learning how to use it, and you certainly don’t want it to be so expensive you can’t afford it in the first place. In a crisis this is true more than ever, as good technology can be priceless by helping people talk to each other, move money, keep medicines safe, and even keep sharks at bay.

Balloon internet and mobile money
To bring the internet to remote areas, Google has been developing balloons that will provide web access for people on the ground below. This is a great idea for areas struck by natural disaster, as people can communicate with each other, and coordinate aid and rescue efforts when equipment on the ground has been damaged. Google’s ‘Project Loon’ has seen 30 superpressure balloons launched from New Zealand, where the idea is that they will drift around the world on a controlled path. Each balloon is 15 metres in diameter and fly 20 kilometres above ground, higher than any plane. Solar panels are used to power the electronic equipment, which includes a radio antenna, flight computer, and an altitude control system.

Using mobile phones for banking is slowly becoming popular in the United Kingdom, but it is still not a very common way to handle money. But in many African countries, the opposite is true. In Kenya, a mobile banking system called M-Pesa has become one of the most important tools to move money. The reason for its popularity is because it’s so easy to use: you buy phone credit, and then use that to pay for things on your phone. There is no need to have a debit card, which is another reason the system has become so widespread: most people in Kenya don’t have a bank account, but lots have mobile phones. Last year there were over 150 companies providing mobile money services to people in Africa, Asia and the Middle East, with over 82 million people using the service.

Clean water and safe vaccines
Making sure there is plenty of clean water to drink is probably the most important thing in a disaster. We can survive for weeks without food if we have to, but we can’t go more than three days without water. There are several ways to purify water, but in a disaster you need one that is small and easy to move, simple to use and not breaking too easily, and probably most importantly: cheap. One option is a small device being developed by an American university working with Engineers Without Borders. The device has a ceramic filter that stops contaminants from coming through, and uses a mixture with burned coconut shells to clean the water by stimulating an active-carbon process. The cheap system has been approved by the World Health Organisation.

When there is no electricity, solar-powered lamps can be used. They work by absorbing solar radiation during the day, so they can emit light at night. Alternatively, they can be used to charge mobile phones. Charities sent thousands of solar lamps to the Philippines after last year’s typhoon. Solar power can also be used to power mini-refrigerators, as many types of vaccinations need to be kept cold. Doctors and nurses working for a charity in Malaysia are currently using a fridge that can stay cool for several days without needing re-charging. This makes it a lot easier to keep medicines safe when travelling to remote areas, or to places with extreme temperatures.

Twitter for help and warning
The Twitter network is great for spreading information to people quickly when something happens. A good example of this is when people wanted to help with the clean-up after the London riots a couple of years ago. Twitter became the best way to organise this, because people could search for clean-up teams in their local area. TV would report the news, but keeping track of who was doing what in each neighbourhood was best left to Twitter. Another point is how the TV channels focused on the destruction, while those following the #riotcleanup hashtag on Twitter saw a different story: how neighbourhoods were pulling together, and thousands of people showed up to fix what had been broken.

Sharks may not have hands to type messages to send to Twitter, but in Western Australia, that is not a problem. Scientists have tagged hundreds of sharks with transmitters, meaning messages will automatically be sent to Twitter if they go too close to the beaches. This will hopefully keep people safer while swimming, as they now learn of nearby sharks a lot quicker than they used to. The sharks, many of them being great whites, are safer too, as beach security is an important issue in Australia. Fewer incidents with swimmers and surfers would make it easier to defend sharks from being culled.

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