Table of contents for Issue 199 in How It Works

Issue 199 “Our memory is ever-evolving, and forgetting should be considered more of a superpower” Most will have had moments when a word is on the tip of their tongue, yet they can’t recall what it is. You might have forgotten an event or an experience in your past that you were only reminded of by a friend repeating the details back to you. You might be one of those forgetful people who regularly forgets or misremembers dates, facts and figures – to the chagrin of friends and relatives. All of these are different types of memory lapse that are usually normal and – you’ll be relieved to hear – completely healthy. In this issue, we put human and animal memory under the microscope to discover which parts of the…

CORE 2 £219 (APPROX. $269.50) SOUNDBRENNER.COM Swinging metronomes step aside – the Core 2 is here to give musicians a new, digital way to maintain their rhythm. Built to look more like a smartwatch, the Core 2 is a feature-packed vibrating metronome that can be worn around your wrist or extended to fit around your body. Just by tapping its interface, musicians can set the pace of their practice session as well as track their performance and monitor decibels and pitch. AERODRUMS £199 (APPROX. $245) AREODRUMS.COM If you love playing the drums but don’t have room for a drum kit, then why not use Aerodrums for a virtual performance? Using a high-speed camera and a pair of reflective drumsticks, Aerodrums can track your hand movements to hit the corresponding drum…

Step into any supermarket and the vast array of food on display could easily make you think that the world is our oyster and we, the species at the top of the food chain, can gorge ourselves on anything we can find. But this is far from the truth. We haven’t got the digestive system to process some plants, while others could put us in mortal danger if ingested. So why are certain plants dangerous? To avoid being eaten. And while some plants have evolved thorns to ward off hungry herbivores, others produce toxins that incapacitate or even kill any animal foolish enough to munch on them. Some of these potential assassins look surprisingly benign. Take oleander, a common garden plant with delicate pink flowers. It contains oleandrin, a cardiac…

When the world was rocked by a giant asteroid 66 million years ago, the dominion of the giant dinosaurs came to a swift end. No longer did the thunderous footsteps of the Tyrannosaurus rex echo through prehistoric forests. Earth had, for a time, lost its tyrannical predators, allowing an era of mammals and birds to follow. But among the species that survived the aftermath of the asteroid impact were small avian dinosaurs – the ancestors of modern-day birds. In an odd evolutionary twist, some of these avian species slowly started to look more and more like the dinosaurs they had outlived. Ditching the ability to fly – a talent that saved their ancestors from extinction – the wings of some of these birds became smaller and smaller even as their…

Modern vehicle brakes are more technologically advanced and smoothly operated than those built for the first cars. But the core mechanism has remained largely the same. The first car brakes involved the driver’s muscle power, as they were required to pull a lever that pressed wooden pads against the wheels. If they didn’t apply enough force, the wheels wouldn’t stop. Today, hydraulic systems are in place, but they rely on the same physics – using friction to slow the movement of the vehicle’s wheels. In modern vehicles, the force is delivered to each wheel via the simple push of a pedal. The driver doesn’t need to use as much force as the wheels require to stop them. This is because the fluid used in the brakes is pushed out from…

Rust is the mortal enemy of iron and the destroyer of nuts, bolts and bicycle handles around the world. Just a touch of water and any metal that contains iron is slowly corroded, transformed into a brittle orange ghost of its former self. On the surface, rust is simply the formation of iron oxide. It’s created in an oxidation reaction, where iron and oxygen bond together. However, the reaction needs a little help from water to get things going. When water and atmospheric carbon dioxide combine, they create a very weak carbonic acid. When carbonic acid sits on iron metal, it begins to dissolve it, and the iron atoms are then free to bond with oxygen atoms in the acid to form rust. The best way to prevent rust from…

Hellcat turned coral nursery At the bottom of the Ferguson Passage in the Solomon Islands are the remains of a Grumman F6F Hellcat. Shot down during World War II, the US fighter plane sank just nine metres, making it one of the world’s most accessible wrecks. Several coral species have colonised the wreckage because it offers a surface for coral larvae to settle and grow. The middle of a mouse This was taken using fluorescence microscopy and shows a cross-section of a mouse embryo. Using fluorescent dyes highlights organs in the developing body of the mouse. The circular structures at the base are the mouse’s small intestine, which sits beneath the liver. Humans and mice share lots of genetic similarities during development, which makes them a good model for scientific investigation. Butterfly bonanza…

Have you ever entered a room, only to forget what you went in there to do? Scientists think that the brain interprets entering a doorway as a new place and a new scene, causing you to temporarily erase your train of thought – the short-term memory of why you went there in the first place. This is just one of the brain’s many memory quirks and tactics. And while forgetting can be frustrating, the human body can only function with a balance of erased and consolidated memories. Your memory shapes who you are, connects chronological events, provides meaning to your surroundings and allows you to form relationships. Your memory also serves as a survival tool, keeping you alive. By learning what’s dangerous and remembering simple information such as where you…

In the Black Hills region of South Dakota, four stony-faced presidents gaze out from Mount Rushmore. This national monument depicts George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln, representing the US’ birth, growth, development and preservation respectively. Not only do these sculptures embody these themes of past events, they also encourage tourism, with nearly 3 million people visiting the mountain’s mighty features each year. The idea for Mount Rushmore came from South Dakota state historian Doane Robinson. The project was no easy endeavour, as it required 400 workers to complete. Because construction began in 1927 and continued through the Great Depression, when unemployment levels were extremely high, many of the workers were desperate for any job available, including this high-risk and strenuous task. Some reported being scared of heights,…

The world as we know it has ended. A particularly virulent strain of avian flu has killed most of us before quarantine orders could be implemented. Or maybe a rocky asteroid a few miles across has slammed into our planet, fatally changing the atmospheric conditions. Or tensions between two countries have reached breaking point, and one or both have taken the nuclear option. In the end, it doesn’t really matter how – the world as we know it is over and the crucial question is, what now? Post-apocalyptic worlds are the stuff of so many novels and films. The immediate aftermath is often portrayed as barren and violent, with roving bands of scavengers hoarding supplies of food and preying ruthlessly on those less well organised or armed. For a period…

GROW GUMMY BEARS Will they double in size, shrink or disintegrate? Their allocated container decides their fate 1 GATHER YOUR MATERIALS You don’t have to experiment with all of the solutions listed in the kit list. Feel free to try out other liquids if you wish to conduct your own experiments. 2 PREPARE THE WATER Fill the first container with water. For the second, fill a microwavable cup with water and heat in 30-second intervals until fairly hot, but not boiling. You can also use a pan on the stove to heat the water. 3 DISSOLVE THE SALT Pour some of the hot water into the second container and add a spoonful of salt. Stir the solution until the salt has dissolved and keep adding more until the granules don’t…

The concept of love has tormented the minds of philosophers, artists and musicians for millennia, but this cheek-flushing feeling can be boiled down to simple chemical reactions. Behind the romantic gestures, the human body is paddling through a whole host of chemicals that make us feel infatuated with another person. In the same way that melanin makes you sleepy or cortisol causes stress, this gravitation to another person is an emotion piloted by molecules in the body called hormones. They help ignite the initial spark of lust, fuel attraction and supply the cosy feeling of attachment. And it all starts in the brain. Throughout the body are glandular cupids waiting to release love hormones straight into the body’s bloodstream as soon as the brain gives them the order. When the…

For the first time ever, researchers managed to decipher what chimpanzee gestures mean. Scientists figured out what’s behind 66 gestures, providing an insight into chimp society. Psychologists at the University of St Andrews spent over two years studying 80 chimpanzees from the Sonso community in Uganda’s Budongo Forest. “It has been known for over 30 years that chimpanzees communicate in this way,” explained Professor Richard Byrne. “But nobody has attempted to answer the obvious question: what are these apes actually trying to say?” The scientists captured over 4,500 gestures using video cameras. Meanings include ‘climb onto my back’, displayed by showing the sole of one foot to another, and ‘flirt with me’, which was signalled by nibbling on a leaf. The researchers discovered that several gestures appear to mean several…

Sudoku Complete the grid so that each row, column and 3x3 box contains the numbers 1 to 9 EASY MEDIUM HARD Word search Find the following words LOVE FORGET TOILET EYES RUSHMORE RUST SYRINGE BRAKE TINY COMBAT STATION TERROR What is it? Hint: Red-hot hole in a mountain A Spot the difference See if you can find all six changes between the images below Answers Find the solutions to last issue’s puzzle pages Q1 200 YEARS Q2 ISAAC NEWTON Q3 GENERATION Q4 ICE AND ROCK Q5 TIKTOK Q6 F-14 TOMCAT What is it? ICICLE Spot the difference QUICKFIRE QUESTIONS Q1 What is the widely accepted theory of the origin of the universe called? • Big Bang • Little Pop • Large Expansion • Great Creation Q2 Which planet does the…

3.5 MILLION DEGREES CELSIUS No one knows why the Sun’s outer atmosphere is much hotter than its surface Ice cream is a solid, liquid and a gas 10,200 There are thousands of active satellites in orbit around Earth 18 CENTIMETRES The largest megalodon shark tooth found is as long as a man’s hand 372 MILLION YEARS AGO The first known seed-bearing plants appeared in the Famennian age THERE IS A MASSIVE ‘GRAVITY HOLE’ IN THE MIDDLE OF THE INDIAN OCEAN 3,830 MILES PER HOUR The latest hypersonic missiles can travel at five times the speed of sound 1928 In this year, the UK, US and Germany signed a treaty to ban war $83 BILLION The world’s largest, most valuable gold deposit was recently discovered in China WATER GETS LIGHTER AS IT…