“We don’t know what makes sleep restorative”

Issue 203

Grasshopper supper

In the forests of Sulawesi, Indonesia, the cute-but-deadly

A pharaoh discovered

© Getty In 1922, British archaeologist Howard Carter,

Ariane in the air

On 6 March 2025, the engines of Europe’s

Scaly mosquitos

© Getty If you take a closer look

Solar wind could be making water on the Moon

SPACE

Elusive colossal squid finally caught on camera

The juvenile colossal squid was filmed near the

AN INCREDIBLE PHOTO CAPTURES THE SUN RISING BEHIND THE WORLD’S LARGEST TELESCOPE

The Sun rising behind the Extremely Large Telescope

Severe drought helped bring about a ‘barbarian’ invasion of Roman Britain

ARCHAEOLOGY

THE UNIVERSE MAY REVOLVE ONCE EVERY 500 BILLION YEARS

The expansion rate of the universe seems to

Lab-grown teeth could offer alternatives to implants

“Lab-grown teeth would naturally regenerate, integrating into the

A ‘MILITARY OUTPOST’ MIGHT BE THE BIRTHPLACE OF ALEXANDER THE GREAT’S GRANDMOTHER

ARCHAEOLOGY

China’s ‘2D’ chip could soon be used to make silicon-free chips

Researchers in China say they have created a

Study reveals a ‘flawed argument’ in the debate over when plate tectonics began

Earth’s first crust looked surprisingly like today’s ©

‘Fingerprints of cancer’ found after infrared light was flashed at samples

HEALTH

Winter sea ice cover is at its lowest in a 47-year satellite record

Winter sea ice cover has dropped to its

SCIENTISTS SPOT A ‘DARK NEBULA’ BEING TORN APART BY INFANT STARS

Circinus West is a vast star-forming region 2,500

WISH LIST

DELICIOUS DESSERT GADGETS

Is Voyager 1 in interstellar space now?

Amazing answers to your curious questions

WHEN IS A SPECIES CLASSED AS ENDANGERED?

The International Union for the Conservation of Nature

WHY DOES SCANDINAVIA HAVE SO MANY ISLANDS?

The multitude of islands dotted along Scandinavia’s coastline

Why does a spicy chilli feel hot, but doesn’t burn you?

© Alamy / Shutterstock Hot chilli

BRAINDUMP

SEND YOUR QUESTIONS TO: HOW IT WORKS MAGAZINE

WHAT WAS THE LAST DINOSAUR STANDING?

The last dinosaur was probably Triceratops . Fossils

Why are some fungi deadly?

Many fungi have evolved toxins to stop animals

WHAT’S THE MOST COMMON DISEASE IN THE WORLD?

The most widespread infectious disease in humans worldwide

Why do we laugh?

Laughter has evolved primarily as a social cue,

How do people walk over hot coals?

© Shutterstock / Getty Firewalking is possible thanks

What will replace the ISS once it’s decommissioned?

The simple answer, unfortunately is that nobody knows

What’s the difference between lunar and solar calendars?

Solar calendars are based on the year –

HOW DOES NASA’S EVOLUTIONARY XENON THRUSTER (NEXT) WORK?

NEXT is a solar-electric engine, commonly known as

WHAT IS SEPTIC SHOCK?

© Shutterstock / AdobeStock Septic shock is a

SUPERQUESTERS MISSION: RIVER CREST RESCUE

The latest book releases for curious minds

USELESS ETYMOLOGY

OFFBEAT WORD ORIGINS FOR CURIOUS MINDS

WHAT IF… YOU DIDN’T MAKE SNOT?

PLUS OTHER AMAZING HUMAN BODY QUESTIONS

THE ULTIMATE KIDS’ GUIDE TO LIFE SKILLS

101-PLUS PRACTICAL TOOLS FOR UNLOCKING POTENTIAL AND BROADENING HORIZONS

MAKE YOUR OWN RAINBOW

A COLOURFUL APPROACH TO ALL THINGS STEAM

Spot the difference

See if you can find all six changes between the images below

QUICKFIRE QUESTIONS

Q1 How much dark matter is the universe

MAKE SUGAR CRYSTALS

Practical projects to try at home

NUT NUTRITION

Speak your mind

ELECTRIC FUTURE

Dear HIW , More cars are becoming electric, which is good for the environment. But are there any downsides? How much more electricity would be needed if all vehicles were fully electric?

WHAT IS A WEED?

Dear HIW , What is the difference between a weed and other plants? Many of them flower and seem to be pretty, so why is it that we view them negatively and remove them from our gardens?

SKI SCIENCE

Dear HIW , I learned to ski this year. I also learned how to snowplough. How does this slow you down?

MAKING MARKERS

Dear HIW , What is in permanent markers to make the ink permanent?

WHY DO WE SLEEP?

A good night’s rest is an essential part of life, but getting enough can be hard. We take a look at the science behind snoozing and how you can sleep easy

SLUMBERING IN STYLE

Posture encourages good sleep quality, so your pillow and mattress can make all the difference

HOW INSOMNIA AFFECTS YOU

MAKING THE BED

Hybrid mattresses have recently skyrocketed in popularity. Here’s a breakdown of what their designs offer

SLEEPY SUBJECT

Vladyslav Vyazovskiy reveals what animals can tell us about sleep and what trackers can’t

5 FACTS DREAMING ON

1 SHADES OF SHUT-EYE While 12 per cent

SCHOOL SCIENCE ESSENTIALS

Take a tour of a classroom laboratory and discover how your school’s scientific instruments work

CONTROLLING CURRENT FLOW

The word ‘rheostat’ comes from the Greek ‘rheos’,

CHANGING COLOURS

How different paper indicators react with acids and alkali

DO LAB COATS MAKE YOU SMARTER?

Before white lab coats, scientists and doctors traditionally

GETTING A CLOSER LOOK

Raising or lowering the slide platform will focus

UNBREAKABLE BEAKERS

Borosilicate was invented in 1887 by German scientist

MOVING AROUND WITH MAGNETS

Did you know? The first magnetic stirrer was

FINDING THE RIGHT FLASK

Which glassware would best suit your experiment?

CLASSROOM CLEANUP

Where do all the dirty beakers go when

KITCHEN SINK CHEMICALS EXPLAINED

Every home has an armoury of liquids to combat stains and leave surfaces germfree. But how do they do their job?

HOW SOY SAUCE IS MADE

This salty, traditional Chinese seasoning is the product of fermented crops

NATIONAL FLOWERS OF THE WORLD

Why some countries have picked beautiful blooms to represent them

GREEK TEMPLE CONSTRUCTION

How ancient architects erected some of the world’s most famous places of worship

TOUR GUIDE TO MARS

Pack your spacesuit and get ready to tick off the must-see sights of the Red Planet

WHAT IS THE GREAT ATTRACTOR?

Head for the stars and discover what it is that makes the Great Attractor such a magnetic idea

AMAZING SELFSAILING BOATS

From a modern-day Mayflower to flying water taxis, autonomous vessels are taking their crews farther than ever across the world’s waterways

DATA FROM THE DEEP

The Mayflower Autonomous Ship (MAS) uses AI and solar power to study the seas

URBAN NAVIGATION

These autonomous innovations are transforming city commutes

WORLD’S FIRST AUTONOMOUS ELECTRIC SHIP

The Yara Birkeland cargo ship is fossil-fuel free with no humans required

A FERRY FIRST

The Soleil ferry is 222 metres long ©

WHY ANIMALS PLAY

From bees playing ball to snowboarding birds, is there reason to animal recreation?

BRAIN GAME

What goes on inside a dolphin’s head during ocean playtime?

RAT HIDEAND-SEEK

DID YOU KNOW? Macaques have been trained to

ELEPHANT PECKING ORDER

Elephants are taught the social structure of their

CLEVER CORVIDS AND AERIAL ACROBATICS

Crows and ravens are among some of the

WHALE OF A TIME

When it comes to entertainment in the ocean,

GAMING AS GROWN-UPS

DID YOU KNOW? American zoologist Vladimir Dinets used 3,000

TYPES OF PLAY

Crocodiles demonstrate all three of the core play behaviour types

REDISCOVERING THE DINOSAURS

They’re often depicted as huge, scaly beasts, but new discoveries are changing our beliefs about the creatures that once stalked our planet

WHEN IS THE NEXT ICE AGE?

By following Earth’s journey around the Sun, scientists are able to predict the next deep freeze

EARTH’S ICE-INDUCING BEHAVIOUR

How changes in the way our planet orbits the Sun can disrupt the seasons and bring about an ice age

5 FACTS THE FIVE BIG FREEZES

1 HURONIAN From 2.5 to 2.2 billion

WHAT IS THE WATER TABLE?

Get to grips with groundwater and discover where it comes from

WHERE THE WATER ENDS

There are several layers of water-logged earth beneath our feet

A DEPLETING RESOURCE?

As a source of fresh water, people have

HOW ELECTRICITY GETS TO YOUR HOME

From power plant to plug socket, follow the journey electricity takes before it reaches our homes

THE ROUTE TO POWER

How energy is generated and transported to our neighbourhoods

HOW WAVE POOLS WORK

What technology is used to sculpt the perfect wave?

WAVE POOL TYPES

1 AIR COMPRESSION These wave machines work

BUILDING A SUPERSCRAPER

Stretching into the sky, the Burj Khalifa in Dubai is by far the tallest human-made structure ever built, and its design will enable us to build even higher

GOING EVEN HIGHER THAN BURJ KHALIFA

The Burj Jeddah in 2021 © Alamy /