Table of contents for Issue 203 in How It Works

“We don’t know what makes sleep restorative” If humans didn’t need to sleep, how much more could you get done every day? Maybe you could use that time to learn to play an instrument or speak a new language, write a book, read more, hang out with friends (who don’t sleep either), binge-watch a series or have a long siesta because you want to, not because you need it. On the surface, it might seem as if sleep is a colossal waste of time – a whopping third of our lives is spent on our backs catching Zs, after all. And though we don’t know exactly why seven or so hours of rest a night is so restorative, we do know what happens when we’re deprived of it. This issue,…

PROFESSIONAL ICE CREAM MAKER £149 (APPROX. $199) PROCOOK.CO.UK As summer approaches, homemade ice cream will be a welcome addition to any kitchen. In just 60 minutes, you can craft your favourite frozen treats with the ProCook Professional Ice Cream Maker. Without any pre-freezing required, simply add your favourite ingredients or experiment with some new ones to make an endless number of flavours. The machine also comes with a 1.2-litre mixing bowl to make enough ice cream for the whole family. For non-dairy eaters, there’s also an option to make delicious sorbets instead. VONSHEF ELECTRIC YOGHURT MAKER £34.99 (APPROX. $46.70) VONHAUS.COM Yoghurt seems like one of those foods you wouldn’t necessarily try to make at home. However, with the help of this nifty gadget by Vonhaus, it couldn’t be simpler. With…

BLEACH THE STAIN REMOVER Bleach is a general-purpose cleaning product that disinfects and removes colour from organic stains. However, the same reaction that removes stains also damages organic fibres, so today bleach is far more likely to be used as a toilet cleaner thanks to its antimicrobial properties. Bleach is commonly a solution of a pale yellow-green chemical called sodium hypochlorite. This breaks down ‘chromophores’, the parts of some molecules that absorb certain wavelengths of light so that only some are reflected, giving colour. Until recently, little was known about sodium hypochlorite’s antimicrobial action, but it’s now thought it causes a microbe’s proteins to unfold, destroying them. Sodium hypochlorite decomposes slowly in water, releasing chlorine, which explains bleach’s characteristic smell. The reaction is slowed by the presence of an alkali,…

Since the 8th century BCE, the ancient Greeks erected elaborate sanctuaries across Greece to worship the deities of Mount Olympus. As symbols of earthly homes for the gods, such as Zeus, Aphrodite and Poseidon, these sacred buildings were places for people to pay their respects and pray. Typically oblong-shaped, these temples were simple four-walled buildings with columns, and have become synonymous with ancient Greece. To support the weight of the temple roof, these columns were predominantly made from marble, a hardy form of limestone that has metamorphosed under extreme heat and pressure deep underground. This resource, abundant in Greece, became commonplace as both a construction material and a medium for sculpture. However, quarrying and transporting the stone was expensive, labour-intensive and timely. In some cases, such as the construction of…

NUT NUTRITION Dear HIW, Are nuts good or bad for you? I’ve heard both claims. How nutritious are they and how do different nuts rank? Jane Stevenson Generally, nuts are very good for you. They contain lots of healthy fats, protein, fibre, vitamins and minerals. Consuming nuts as part of a balanced diet has been shown to improve heart and brain health, lower cholesterol, control blood sugar and provide anti-inflammatory effects. It’s likely that anyone claiming they’re unhealthy is referring to their energy-dense nature. Over-eating nuts can cause weight gain more easily, but as long as you stick to recommended serving sizes, your body will be better for eating them. It’s difficult to rank nuts in healthiness unless you consider specific qualities. Raw or dry-roasted and unsalted nuts are the…

Grasshopper supper In the forests of Sulawesi, Indonesia, the cute-but-deadly spectral tarsier can be found. As the world’s only entirely carnivorous primate, tarsiers like to feast on prey such as moths, cicadas, small snakes and lizards. This predator seems to have found an unfortunate grasshopper to snack on. As nocturnal creatures, tarsiers hunt by moonlight and have been dubbed ‘lunar philia’, meaning they’re more active during a full Moon. A pharaoh discovered In 1922, British archaeologist Howard Carter, along with his benefactor Lord Carnarvon, stepped inside the tomb of Tutankhamun for the first time. The two outermost coffins were made from wood that had been painted gold and set with brilliant semiprecious stones, such as lapis lazuli and turquoise. The inner coffin was forged from solid gold and weighed around 110.4…

It takes up a third of our lives and seems to be a non-negotiable part of being human, but what exactly is sleep and why is it essential? Sleep is often defined as a state of rest, and it does appear that way from the outside. However, our brains and bodies are working overtime. During sleep, the brain and body go through a schedule of events known as sleep cycles. We typically go through six cycles per night, and each one is made up of four stages. Stage 1 is the period when you first doze off, and it lasts up to seven minutes. Stage 2 lasts for up to 25 minutes and is accompanied by muscle relaxation, a slower heart rate and a cooler body temperature. Next up is…

Soy sauce was first made 2,200 years ago in ancient China. It’s produced when a paste made of soybeans and wheat is left to ferment. During soy fermentation, the Maillard reaction takes place. This chemical reaction occurs when the amino acids and sugars in the paste turn it brown and produce new flavours and aromas. The unique flavour is created by the breakdown of soy proteins into free amino acids and peptides. The result is an umami flavour. Umami is one of the five basic tastes, providing a rich, meaty or brothy flavour. In soy sauce, this can make dishes taste meatier. The process of making soy sauce stems from another ancient Chinese sauce called jan. This was used when pickling foods in salt to prevent them from spoiling, and…

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 SLEEP PLAY ICE TABLE FLOWER GREEK SCHOOL SNORE WAVE POWER BOAT SOY What is it? Hint: Also comes in the form of hair 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 FLINT Q2 248 MILES Q3 FISSION Q4 HYDROGEN Q5 1,000 Q6 TIGER What is it? TREE STUMP Spot the difference QUICKFIRE QUESTIONS Q1 How much dark matter is the universe made of? ○ 15 per cent○ 27 per cent○ 52 per cent○ 88 per cent Q2 Why do the pupils of your eyes constrict?…

HORSES, ELEPHANTS, ZEBRAS AND BISON SLEEP STANDING UP £325 BILLION The richest person ever was Mansa Musa, a 14th-century African emperor 1992 33 years ago, the first photo was uploaded to the internet A jar of honey won’t go bad for thousands of years 15.47 BILLION ‘Baby Shark Dance’ is still the world’s most viewed YouTube video 04:00 The first alarm clock, invented in 1787, would only go off in the early morning 10% Your left lung is slightly smaller than your right 1, 200 MILES PER HOUR Neptune’s winds can blow nearly five times harder than Earth’s most powerful hurricanes DOGS HAVE TWO SEPARATE AIRWAYS FOR BREATHING AND FOR SMELLING 3,700 BCE Woolly mammoths were still around when the pyramids of Giza were being constructed…

SPACE Solar wind could be making water on the Moon WORDS DAMIEN PINE Constant gusts of particles from the Sun may be creating water molecules on the Moon, a new NASA-led experiment hints. Scientists have detected traces of water, as well as hydroxyl (OH) molecules, a component of water, on the surface of the Moon through multiple space missions. The source of this water has long been a mystery, though some theories suggest volcanism, outgassing from deeper in lunar regolith – the combination of rock and dust on the surface of the Moon – and bombardment by tiny meteorites. The new NASA experiment tests a different idea: that solar wind is behind it all. Solar wind is a constant gale of charged particles streaming from the Sun at over a…

DID YOU KNOW? The European Organization for Nuclear Research (CERN) is the largest laboratory on the planet, spanning around 3.4 miles BRINGING THE HEAT What would a school laboratory be without an iconic Bunsen burner? These experiment staples have been around since German chemist Robert Bunsen’s pioneering invention in 1855. Fed up with choking on the soot that early laboratory burners released, Bunsen created a way to control the level of oxygen from the air that mixed with the gas fuel of the burner without producing soot. His design looked similar to the modern-day instrument, including the chimney-like barrel and all-important adjustable air holes that control the intensity of the flame emitted by the burner. The more air that enters the burner, the hotter the flame is. The Bunsen burner…

There are up to 400,000 different species of flowering plants across the world, ranging in size, colour, shape, scent and many other characteristics. Some species are widespread, while others can only be found growing in certain countries or regions. Pleasing to both the eyes and nose, for thousands of years humans have spread flowers across the globe and bred them to be more fragrant or attractive to us. Flowers have inspired humanity with their beauty and are able to evoke deep emotions within us. Since antiquity, flowers have been ascribed meanings and have become symbolic of concepts like love, wisdom or purity. Many countries have adopted botanical national emblems. These are often chosen because they’re associated with the history, culture or mythology of a nation, becoming part of its identity.…

MAKE SUGAR CRYSTALS Watch as crystals emerge from a colourful sugar solution 1 GATHER YOUR MATERIALS Make sure you have all of your materials before starting. Food colouring is optional to create vibrant results. 2 POUR INTO PAN Pour your sugar and water into a pan. You will need three cups of sugar for every one cup of water. 3 MIX AND COMBINE When you mix the sugar and water together, you’ll see that it doesn’t change much. Put the pan onto heat and continue to mix as the water is brought to a boil. 4 LEAVE TO COOL You should see that the sugar has dissolved in the boiling water. Take the pan off the heat and leave the water to cool a little. 5 FILL THE JARS Distribute…