Innholdsfortegnelse for You: Did you know? 2018 i You South Africa

YOU’RE LOST! NOW WHAT? ▪ First things first – don’t panic! If you run around in a distressed state, chances are you’ll get even more lost. ▪ Look around – are there any familiar landmarks such as a hill or tree? Often these can help you reorient yourself and get back on the right track. ▪ Don’t wander too far from where you are. Chances are someone in your hiking group has realised you’re missing and they’ll send someone to find you. ▪ If you know how to get back to the spot where you wandered off the trail, try to get back. If you have no idea, rather stay put. ▪ The rescuers still haven’t shown up and you’re getting thirsty. When you look for water make sure to…

WHAT’S HIBERNATION? Imagine sleeping for five to seven months every year! This long continuous rest period during winter is called hibernation. Many animals – including bears – go through this deep sleep process to escape the harsh cold winters because food is scarce. HOW DO THEY DO IT? The animals know the first step for a good winter sleep is to prepare properly. Bears, for example, overeat in the months just before winter in the northern hemisphere – they need the extra food because they don’t eat while sleeping. When they hibernate their metabolism (rate at which bodies use food for energy) and other bodily functions such as breathing and heart rate work at just a quarter of their normal rate. This means that the stored fat in their bodies…

WHERE IT’S FOUND The peregrine falcon is a bird of prey and lives nearly everywhere on Earth except in polar regions such as Antarctica, extremely high mountains and most tropical rainforests. The only relatively large landmass where it isn’t found is New Zealand. This makes it the world’s most widespread bird of prey. THE SPEED RACE Usain Bolt 44,7km/h Racehorse 70,7km/h Cheetah 115km/h Sailfish 110km/h Peregrine falcon 389km/h Bugatti Veyron 431,3 km/h The peregrine mates for life These falcons typically nest on high cliffs. The female lays two to five eggs (actual size, left) at a time and the eggs hatch after about 32 days in the nest. How does it reach such incredible speeds? 1 The peregrine falcon is a skilled hunter that relies on its superior speed to…

WHERE IN THE WORLD? The kakapo is indigenous to New Zealand but extinct on the two main islands? North and South. The surviving birds are kept on four small predatorfree islands? Anchor, Codfish, Maud and Little Barrier. As of June 2017 the total population was 154. SIZE The species is the world’s heaviest parrot – males weigh 3-4kg while females weigh about 1,5kg. They grow to about 60cm at maturity. Because they don’t use their wings to fly they have the smallest relative wing span of any parrot. DEFENCE The kakapo is vulnerable because of its inability to fly. To hide from New Zealand’s birds of prey it became active at night and developed green and brown plumage as camouflage for when it rests under trees in the day. MATING…

DOLPHIN COMMUNICATION Scientists believe most dolphin species, such as the bottlenose dolphin, use a range of sounds to communicate, including whistles, clicks and screams. Each one has its own signature whistle, almost like a name, so they can identify one another. Dolphins seem to have a different whistle for different situations. And scientists say they teach the whistles to new members of their pod. Some species, such as the rare Hector’s dolphin, (found near New Zealand) doesn’t whistle at all. It uses pulsed sounds (clicks). DOLPHIN’S ECHOLOCATION SYSTEM The dolphin has a sensory system to detect objects underwater by using the echoes created by sounds (echolocation). Sound travels four times as fast in water as in the air. The dolphin’s eyesight is fine above water but the murkiness underwater makes…

SCIENTISTS believe a giant meteorite collided with Earth about 65 million years ago and wiped out all the dinosaurs. Let’s take a look at how a big rock from space could cause so much damage. 1 THE METEORITE This space rock was 10km in diameter and left a crater 180km wide and 30km deep. That’s the size of Gauteng! The giant hole is called the Chicxulub crater and you can find it in Mexico. Its centre is near the town of Chicxulub. 2 THE DUST CLOUD When the meteorite slammed into Earth’s surface it created a giant explosion. Rocks and dust shot into the sky. Our planet was completely enveloped by a thick cloud of dust, which blocked out the sun’s rays and caused a long, dark, cold winter. 3…

Meaning Speedy thief Pronunciation vuh-LOSS-ih-RAP-tur THE fast velociraptor and its kin are among the closest relatives to birds. It had a number of bird-like features including foldable wrists and large feathers, but probably couldn’t fly due to its small forearms. LIMBS The velociraptor could leap and run great distances on its powerful back legs. BRAIN It was one of the most intelligent dinosaurs. PACK HUNTERS Some experts believe velociraptors were pack hunters, tackling large prey together, just as they were portrayed in the movie Jurassic World. They were fast and sneaky (hence the name), lying in wait for prey. CLAWS The second toe of each foot had a large, retractable claw. New research suggests the velociraptor used its famous 6,5cm-long claws like climbing crampons (metal spikes attached to boots and…

THERE are more than 180 000 islands across the world and a 10th of the world’s population live on them. Some islands form over thousands of years while others appear virtually overnight. Overnight islands • In November 1963 after a volcanic eruption the island of Surtsey emerged about 8km south of Iceland. Initially it was 2,7km², but wind and wave erosion over time has reduced it to its current size of 1,4km².• In 2000 the Kavachi volcano produced the volcanic island Kavachi Seamount in the Pacific Ocean between Papua New Guinea and the Solomon Islands. Newest island The crescent-shaped Shelly Island (named because of the many shells found there) began forming off the American coast near North Carolina in April 2017. It’s 1,6km long and 146m wide, but its size…

ATORNADO is a terrifying natural phenomenon – just ask Dorothy and Toto from The Wizard of Oz. Luckily, South Africa rarely sees tornadoes (only 26 have been recorded since 1948). About 800 twisters (three-quarters of all the tornados in the world) sweep across America every year. In fact there’s not a single state in America that hasn’t been hit by a twister, while Britain is ravaged by about 60 a year. Fortunately, only about 0,1% of all tornadoes are classified as EF5 (with wind speeds of more than 320km/h) on the EF-Scale which measures tornadoes (see below right). HOW DO YOU KNOW IF A TORNADO IS APPROACHING? • The sky turns dark and is sometimes a greenish colour.• A cloud of dust and debris is visible.• You hear a roaring…

WONDER how your bedroom light goes on? An electrical circuit – a system through which energy is passed – carries the electricity needed to operate the light bulb. The circuit must be unbroken to successfully conduct a current. This is how it works. BASIC SYMBOLS These are the most common electrical symbols used in diagrams of electrical circuits. Wire Light bulb Cell Battery Switch A BROKEN CIRCUIT A switch is used to turn an electrical appliance on and off. If the switch is off the circuit is broken (incomplete). If the switch is turned on the circuit is complete and the light bulb burns. Use the symbols above to follow the simple circuit diagrams below. TWO TYPES OF CIRCUITS PARALLEL CIRCUIT Cells are connected in parallel if all the positive…

1 THE TREE The coffee cherries are seeds found inside the Coffea tree’s fruit. They are eaten by the Asian palm civet, a small wild mammal, and pass through the animal’s digestive system to make the expensive coffee. 2 FERMENTATION Fermentation occurs in the civet’s stomach affecting the cherries and giving kopi luwak (which is Indonesian for civet coffee) its special flavour. 3 THE POO The civet can’t digest the coffee cherries and after 24 hours they’re pooped out and collected. 4 PREPARATION & FINISHING The cherries are separated from the poo, washed, peeled and dried before being sorted by hand to remove any damaged ones. They are stored at a constant temperature for a few months to mature and are then roasted. Only about 500kg is produced from wild…

CHEESY FACTS • Cheese can be made from milk from a cow, buffalo, goat, horse, donkey or camel.• Cheddar cheese is naturally white. Yellow cheddar cheese is given its colour by adding a natural plant-based colouring called annatto.•Bacteria in ripening Swiss cheese break down the protein and stretch the cheese, forming holes! STEP 1 HEAT THE MILK Ask an adult to help you to slowly heat the milk in the stainless steel pot until it reaches 38°C. Remove from the heat. STEP 2 ADD THE RENNET Once you’ve removed the milk from the heat, add the two teaspoons of liquid rennet (a curdling enzyme that will make the milk separate into different bits). Mix well and leave it to stand for 15 minutes. The milk will separate into curds at…

I WAS reading to my six-year-old one evening when she asked what makes her bedroom light switch on. I replied without much thought that Eskom switches it on and went back to the story, but she wasn’t satisfied, “but why does it go on when I press the switch”. I remembered it had something to do with positives and negatives and circuits but couldn’t really answer so I opted for distraction. Soon after that work began on the second issue of YOU Did You Know?, and I was so pleased we could include an illustration on how an electric circuit works. It was so simple to understand. That’s what this magazine is about, it answers those questions kids love to ask and parents don’t always have the answers to. You…

CAN’T YOUJUSTSLEEP ON THE GROUND? You could but it would significantly reduce your chances of survival. A good shelter is important for various reasons. ▪ It protects you from the elements − rain, snow, wind and the sun. ▪ You can’t be seen as easily by wild animals or other intruders. ▪ Having a warm place to sleep provides comfort and means you can rest, allowing you to focus on important things such as finding food and water. LOCATION, LOCATION, LOCATION Where you build your shelter is important. ▪ If you’ve found a water source, try to build the shelter nearby (but make sure the ground is dry). That way you don’t have to waste precious energy fetching water. But be aware of animals that use the water source. ▪…

THE BLUE CRANE WORLD Our national bird is part of the crane family and is also known as the paradise crane and the Stanley crane. • Habitat In the past two decades the blue crane has dwindled in numbers across most of South Africa by as much as 90% in some provinces. It’s estimated that only 25 000 cranes are left in the wild. About half the surviving population lives in the Overberg in the Western Cape. They enjoy dry, grassy areas.• Under threat Threats facing the bird include poisoning, illegal trade, habitat destruction, power-line collisions and killing by landowners.• Appearance It’s pale blue-grey in colour with a white crown, pink bill and long, dark-grey wingtip feathers.• Dancing birds When finding their perfect partner, these birds do a courtship dance…

SEAWEED A type of algae and important food source for many animals as well as a source of oxygen. OCTOPUS It builds a den using rocks and eats crabs, worms and whelks. It can grow back a lost limb. SCULPIN This small, spiny fish is a bottom feeder (feeds on the ocean floor) and eats snails, worms and shrimp. NUDIBRANCH A brightly coloured, soft-bodied sea slug that sheds its shell after its larval stage. It eats sea sponges and fish eggs. WHELK This sea snail uses chemicals in its mouth to make holes in crabs’ and mussels’ shells to eat their soft centres. SEA URCHIN It looks like a plant but is an animal and can be venomous. It’s sometimes called a sea hedgehog because of its spines. It eats…

PREDATORS Its only natural predators are: Certain species of shark Killer whales SPEED COMPARISONS Great white shark: 40km/h Scuba diver: 6km/h Killer whale: 48km/h Leopard seal: 38km/h SKULL AND JAWS The leopard seal is built for hunting. It has a large, powerful head. A carnivore, it has large, curving canines. It also has three large cusps on the premolars and molars that interlock. The strong lower jaw is massive and is aided by powerful muscles attached towards the back of the jaw. HUNTING It’s diet consists of krill (tiny shellfish), fish and other marine creatures. But it’s also the only kind of seal that hunts other species of seal. It also loves to eat penguins. It moves fast on land and in the water, so it has no trouble catching…

Meaning Long feather raptor Pronunciation CHANG-yoo-rap-tore IT WAS about the size of a turkey, had four feathered wings and could probably fly. The changyuraptor lived 125 million years ago. “It’s the biggest four-winged dinosaur that’s been discovered to date,” says Professor Anusuya Chinsamy-Turan, a palaeontologist at the University of Cape Town who was part of the team that discovered this dinosaur in 2012. Despite the changyuraptor being fairly big, Professor Chinsamy-Turan and her team believe it could fly, thanks to its wings and an exceptionally long tail with feathers. This carnivorous dino is a distant relative of modern-day birds and enjoyed snacking on dino meat. FEATHERS Feathers cloaked the changyuraptor’s entire body. It also had extra-long tail feathers – up to 30cm long – the longest known feathers for any…

VICTORIA FALLS – LARGEST SHEET OF FLOWING WATER 1989 The year Victoria Falls was declared a World Heritage Site. It’s also one of the seven natural wonders of the world. 20km The distance from which the spray of the waterfall can be seen. The spray is also known locally as “Mosi-oa-Tunya” which means “the smoke that thunders”. 700 000m3 How much water cascaded over the falls each minute when the river flow was at its greatest in 1958. It’s the world’s largest sheet of falling water. 1855 The year explorer Dr David Livingstone was taken to the edge of the falls in a canoe. HIGHEST AND MOST VOLUME WATERFALLS HIGHEST – ANGEL FALLS At 979m high, this waterfall in Venezuela is the highest uninterrupted waterfall above water. It’s just slightly…

CHOCOLATE is a favourite sweet treat of many people and has been around for centuries. The earliest record of it being enjoyed involved Aztec people in Central Mexico drinking hot chocolate in 1100 AD. From the earliest times people ground cocoa beans and used the paste to make drinks. The beans are bitter – the word chocolate is said to derive from Aztec for “bitter water”. When chocolate was introduced much later to Europe, sugar was used to sweeten the drinks. The Aztecs ate chocolate as part of their meals, used it in religious rituals and even demanded cocoa beans as a tax when they conquered a city. But in Europe chocolate was a dessert. The first chocolate bar was made in the 1840s in a factory associated with John…

WORMS eat their own weight in organic waste (such as vegetable and fruit scraps). And their waste (or poop) is the compost which is filled with nutrients that’s good for soil. That’s why a worm farm is so useful for growing plants or vegetables. WHAT YOU NEED Two deep plastic containers with lids (preferably black because earthworms feel at home in the dark) A brick or small flower pot Household waste such as fruit and vegetable peelings About 250g live earthworms. Google “where to buy earthworms in South Africa” to find suppliers in your area. 1 Ask an adult to drill about 20 holes in the bottom of one of the plastic containers and also several holes in the lid. 2 Put the brick or flower pot in the container…

AQUAPONICS might sound as if it’s complicated, but this clever technique is quite simple. If you’ve seen how fish are kept in an aquarium, you already know most of what you need to know about this interesting way of growing plants. Aquaponics is a way of growing fish and plants where each uses the other to grow more effectively. Instead of putting plants in soil, they’re grown in water that has one or more fish in it. It’s a win-win setup: the fish get fresh water from the plants and the plants get nutrients (food), from the fish. You guessed it – the fish poop feeds the plants! Let’s look at this symbiosis in action then see far right for instructions on how to make a mini version using herbs…

DOGS SIGHT Dogs can see colours, but mostly greys, as well as some blues and yellows. Their vision is not as sharp as ours, but they can detect the slightest movement much better than we can. They can also see better in dim light. HEARING Dogs hear very well. They can hear things from a great distance, for instance, they can hear people down the street long before they get to your house. That’s why some dogs are good watchdogs. They can also hear much higher sounds than we can. SMELL This is probably dogs’ strongest sense. They can smell up to a million times better than us. That’s why they’re used to find missing people, drugs, bombs, people buried in the snow and can even detect cancer! CATS SIGHT…

GIANT FEET The polar bear’s huge paws work like snowshoes to spread its weight evenly over the ice and snow. Its claws are used for grasping prey and for traction when running or climbing on slippery ice. Small bumps on the thick black pads prevent slipping. Long hair between the pads and toes help keep its feet warm. HUNTING SEALS During winter the polar bear spends a lot of time on ice floes (sheets of floating ice) off the coast, hunting its favourite food – ringed seals. Ringed seals make holes in the ice floes so they can breathe when they come to the surface and it’s here the polar bear lies in wait. It spends many hours waiting to catch a seal. TRANSPARENT FUR Its fur is transparent but…

1 PEREGRINE FALCON Speed: 320km/h The fastest animal on the planet is also the fastest in the air. To catch its prey the peregrine falcon makes a hunting stoop (high-speed dive), using gravity to reach a speed of 320km/h. The fastest speed ever recorded for this bird of prey is 389km/h. Turn over to read more about this fast flier. 2 CHEETAH Speed: 115km/h The cheetah is speedier than any other land animal and can accelerate from zero to more than 100km/h in just three seconds. That’s about the same as a supercar such as the Ferrari 458. It has unique paws – the semi-retractable claws provide extra grip when it runs at high speed. Its large nostrils allow for increased oxygen intake, and an enlarged heart and increased lung…

OSTRICH FOR SALE • The ostrich is raised for its meat, feathers, skin and claws (which are sold as dog chews).• It gets much of the water it needs from the plants it eats.• Ostrich meat tastes a lot like beef and is healthy because it contains little fat and cholesterol. It’s rich in calcium, protein and iron.• The ostrich usually lives for 30 to 40 years. In captivity it can live for more than 60 years. BIRD’S-EYE VIEW • Its long legs are well-adapted for running. One stride can be up to five metres long (the length of an average family car).• The ostrich uses its wings for balance and to regulate its body temperature. It spreads them slightly when running.• Each foot is equipped with two toes, each…

THIS organism might look like a flower (in fact it’s named after one), but it’s actually an animal related to coral and jellyfish. And though it looks as if it’s rooted to one place, a sea anemone can slide along slowly by moving its foot, or by letting go of the rock it’s holding onto and floating away or swimming by flexing its body. There are about 1 000 species (49 are found along the South African coast). Most live in shallow water such as coral reefs or tidal pools, but some have been found at a depth of 10 000m. WHAT EATS SEA ANEMONES? • Snails and sea slugs • Starfish (sea stars) • Fish such as the mosshead sculpin • Sea turtles such as the loggerhead SEA ANEMONE…

THE sea turtle is one of Earth’s oldest creatures. The seven species that exist today have been around for 110 million years, since the time of the dinosaurs. The leatherback sea turtle, also known as the lute or leathery turtle, is the largest living turtle and the fourth-heaviest modern reptile after the saltwater, Nile and Orinoco crocodiles. It’s the only modern sea turtle that has a group of bony plates covered in leathery skin instead of a bony shell, which is where its name comes from. WHERE IT’S FOUND The leatherback sea turtle has the widest distribution of any reptile and is found as far north as Alaska and as far south as the southern tip of Africa. BABIES Like all turtles, the female leatherback sea turtle lays its eggs…

DID you know Earth’s continents and oceans never stop moving? Hundreds of millions of years ago, the continents as we know them were part of one enormous landmass. Over time this landmass broke up and the pieces started drifting apart, creating the seven continents – Asia, Africa, Europe, Australia, Antarctica, and North and South America. And these continents are still moving today – it’s called continental drift. PANGAEA About 200 million years ago, most continents were part of a huge supercontinent scientists call Pangaea (see right for an idea of how it looked). Pangaea is the youngest supercontinent. Not much is known about the oldest, Rodinia, which existed one billion years ago but it’s belived it was barren (had no life on it). NAMING THE CONTINENTS • Africa was most…

IMAGINE the sight – hot water naturally shooting from the ground as high as 115m into the air! This is known as a geyser, a type of hot spring, and it occurs mainly near active volcanic areas. A specific combination of geological conditions is needed for geysers to exist, so they are fairly rare – there are only about 1 000 known active geysers in the world. WHAT’S A GEYSER? It’s a spring or water source in which the water is hot (thanks to contact with molten rock) and is forced out of the ground under pressure caused by steam. The highest recorded spurt of hot water by a currently active geyser was more than 115m into the air. GEYSER RECIPE • A spring • Underground water reservoir • Hot…

WHAT IS GPS? The Global Positioning System (GPS) is a network of about 30 satellites that orbit (circle around) Earth at an altitude of 20 000km. At least four of these GPS satellites are visible at any time from wherever you are in the world, each one regularly transmitting information about its position and the current time. These signals, which travel at the speed of light, are picked up by your GPS receiver. It then calculates how far you are from each satellite based on how long it took for the messages to arrive. THE GPS IS MADE UP OF THREE PARTS: 1 Tracking stations 2 Satellites 3 Receivers 1 TRACKING STATIONS They use radio waves to figure out the orbits of GPS satellites. 2 SATELLITES A GPS receiver works…

WHAT IS A COMPASS? A compass is a simple device consisting of a magnet (usually in the shape of a needle) balanced on a pivot that allows it to move freely. One side of the needle is marked “N” or has a colour to indicate north. STEP 1: UNDERSTAND HOW MAGNETS WORK • The two sides of a magnet are called the north and the south pole respectively.• If you hold two magnets so that their south poles almost touch, they will push each other away. But if you let north and south pole touch, the two magnets will pull towards each other and “stick”. That’s because magnetic poles that are the same repel each other, while those that are different attract each other. The same principles are used in…

THANKS, DAISY! One dairy cow can produce up to 65 litres of milk a day! WHAT MILK IS MADE OF Milk is made up of 87,5% water and 12,5% solids. The solids are made up of fat, protein, lactose (milk sugar), vitamins and minerals. If you’re not lactose-intolerant (your body can’t process lactose), milk is really good for you! JOURNEY OF MILK 1 The cow’s udders are washed and sanitised. 2 Cows are milked up to twice a day in ventilated rooms called milking parlours. Each milking takes 5-8 minutes and is done by machine. 3 Milking equipment includes four teat cups and a vacuum pump which a farmer gently connects to the cow’s teats. The milk is stored in a cooled tank to prevent bacteria from breeding. 4 The…

FROM SEEDS TWO WAYS TO GROW VEGETABLES You can grow veggies by sowing seeds in the soil or by planting vegetables or parts of them (see below). ONIONS Best time to sow seeds MARCH-OCTOBER Harvest in 6-8 months POTATOES Best time to sow seeds AUGUST-OCTOBER Harvest in 3-5 months TOMATOES Best time to sow seeds AUGUST-DECEMBER Harvest in 4 months CARROTS Best time to sow seeds ALL-YEAR ROUND Harvest in 2½ months FROM VEGGIE PARTS HOW TO PLANT ONIONS STEP 1 NOTE: The onions are ready to be harvested in 3-4 months. ST EP 2 Plant onions with the sprout side up in the soil. STEP 3 Buds (new onions) grow from the base of the existing bulb and need to be replanted. STEP 4 Separate the new bulbs and…

SLIMY GOO… EEWWW! GOOEY SLIME YOU NEED • ¼ cup of white craft glue• mixing bowl• ¼ cup of water• mixing spoon• food colouring and glitter (optional)• ¼ cup of liquid starch (used for clothes) WHAT TO DO 1 Pour the glue into the mixing bowl. 2 Pour the water into the mixing bowl. 3 Use the mixing spoon to mix the glue and water. 4 Add about six drops of food colouring such as green or blue and a little glitter (if you’re using some). 5 Add the liquid starch and stir until the mixture is gooey. As you play with the slimy concoction it will become more stretchy and easier to hold. 6 Store the slime in a ziplock bag or container with a lid when you’re not…