How It Works Brain Dump Issue 032 2016

YOUR REGULAR DOSE OF

INCREDIBLE FACTS

BROUGHT TO YOU BY

BROUGHT TO YOU BY

welcome

Getyourcurious questionsanswered Congratulations! Another science issue of Brain Dump has been delivered direct to your tablet or smartphone. As usual, it’s packed with facts, stats and info encompassing a fascinating range of topics from the worlds of science, Why is rubber so stretchy? space, nature, transport and the human body. Give your hisTorY brain a workout and swipe left to get started.

What does static tell us?

sPace

Holes in the ozone layer

TransPorT

The Abrams M1 battle tank

TechnoLogY

enVironMenT

Why aren’t spiders insects?

How are bottles recycled?

Followuson.. @BraindumpMag www.f/BraindumpMag @BraindumpMag acebook.com/braindumpmag Design: Lora Barnes Photography: Corbis; Getty; Thinkstock; NASA; Rex features

that s

AMAZING Lava flows and molten lava is bubbling up in Hawai‘i Volcanoes National Park, Hawaii. The park is almost 100 years old and encompasses Earth’s largest active volcanic, Mauna Loa, which has been erupting for around 700,000 years.

that s

AMAZING

These polar bear cubs appear to wave at the photographer as they stand alert. The curious cubs are on the lookout as they have just spotted a male polar bear nearby. Their mother, who is out of the shot, stands guard.

that s

AMAZING This image of Pluto has been coloured by NASA scientists to show its varied terrain, including a heart-shaped icy plain, deep craters and enormous mountains, as well as what NASA now believes to be incredibly tall ice volcanoes.

n a can

T n a h P eLe

JuM

As the world’s largest land animal, weighing several tons, elephants are simply too heavy to jump. Their bone structure prevents them from bending their legs enough to push themselves off the ground. Elephants

P?

do not have natural predators so they did not need to be able to jump to improve their chances of survival. Elephants do not even like standing on two legs, although they can be trained to do so.

hoW cLose can You geT To a

rocKeT

Launch? Depending on the agency launching the rocket, you can usually get quite close to a launch. For example, you can view a NASA rocket launch at Kennedy Space Center from the Apollo/Saturn V Center viewing area, which sits about five kilometres (three miles) from its world-famous launch pad. The ESA launches its rockets from its own spaceport, Le Centre Spatial Guyanais in French Guiana. Viewing space is limited, however, and in the case of NASA launches, you have to buy a ticket.

is There a difference beTWeen

Veins and

arTeries? Arteries

Arteries carry high-pressure blood away from the heart.

Veins

Veins carry low-pressure blood toward the heart.

In order to withstand the high pressure as the heart beats, arteries need to be relatively thick and muscular. They resist stretching, helping to maintain enough pressure to push blood around the body without bursting under the strain. However, by the time the blood has travelled through the capillaries and

into the veins, the pressure is much lower. Veins are wider in internal diameter than arteries are, and their walls are much thinner, allowing them to store up to 70 per cent of the blood in the body as it makes its way back to the heart. One-way valves help to keep the low-pressure blood travelling in the right direction.

55 The niLe COOL THINGS

1

It has been suggested that the River Nile was created in its modern incarnation approximately 25,000 years ago when Lake Victoria developed a northern outlet.

2 3

In Ancient Egyptian times the River Nile was known as ‘Ar’, or ‘Aur’, which translates as ‘black’, referring to the dark, fertile sediment that was left behind after it flooded. While the construction of the Aswan Dam has prevented the Nile from flooding yearly in Egypt, it has also reduced its fresh water flow, in turn increasing pollution content.

4 5

The primary source of the Nile is Lake Victoria, which covers an area of more than 69,400 square kilometres (26,795 square miles). Despite its size, it is very shallow and warm.

According to Greek geographer Strabo, the Nile Delta used to comprise seven delta distributaries. Today there are only two: the Rosetta and Damietta.

WhY are

refLecTions

reVersed? Mirrors appear to reverse things from left to right because of our perceptions. Our bodies are roughly symmetrical, so the reflection of your left hand looks just like your right hand. For this reason, we tend to assume that mirrors reverse left and right. But if you hold up an asymmetric object in front of a mirror, for example a saucepan, left and right are not reversed. The right-hand side of the saucepan (for instance the handle) is still on the right, and the left-hand side is reflected on the left. Instead, a mirror inverts front and back.

hoW do We Measure The disTance To gaLaXies?

Astronomers estimate the distances to far-away galaxies by measuring the brightness of their stars. An easy way to do this is to find a type of star called a Cepheid variable, whose brightness varies over time. Astronomer Henrietta Leavitt discovered over 100 years ago that the period of these

fluctuations relates to Cepheid variable stars’ true brightness. By comparing the star’s true brightness to how bright it appears from Earth, its distance can be calculated. Edwin Hubble used this method in 1923 to make the first accurate measurements of how far away the Andromeda galaxy is.

WhY aren’T sPiders insecTs? Insects and spiders are both arthropods with a chitin exoskeleton and segmented bodies, but the fossil record shows that their evolutionary trees separated around 420 to 450 million years ago. Insects all have six legs and three body segments: head, thorax and abdomen. They have a pair of antennae on the head and sideways-moving mandibles for

grasping and chewing. Spiders have just two body segments: cephalothorax and abdomen. They don’t have antennae and instead of mandibles they have hollow fangs, called chelicerae, which stab downward to inject venom. Believe it or not, the differences between spiders and insects are as big as the differences between birds and mammals.

WhaT

iT?

sWiPe To reVeaL

is

The orion sPacecrafT

NASA hopes its new spacecraft will take humans further than ever before, to destinations such as Mars and nearby asteroids. Pictured is a carbon copy, non-functional, structural test model that is due to be tested at NASA’s Plum Brook Station test centre in Ohio, USA.

WhaT is

PerMafrosT? Much of the subsurface soil of Greenland, Svalbard, and the northerly regions of Scandinavia, Russia, Alaska and Canada has been frozen since the last ice age. Continuous freezing and thawing in the top 20 centimetres (7.9 inches), known as cryoturbation, allows meltwater to circulate and keep the soil relatively fertile. But lower layers than this remain permanently a few degrees below

freezing, which can dramatically affect the landscape. Here, drainage is very poor, resulting in boggy ground dominated by mosses and small hills (pingos) pushed up by the ice and deep cracks where water can collect and freeze. Arctic areas with little permafrost (especially southerly forest tundra regions) are host to thick shrub tundra, willows, dwarf birch and other hardy plants.

WhaT Was The fasTesT round-WorLd TriP? According to the Guinness World Records, the fastest aerial circumnavigation (without going into space) still belongs to Concorde. In 1995, the supersonic passenger jet set off from New York, USA, and circled the globe in just 31 hours, 27 minutes and 49 seconds, reaching Mach 2 – twice the speed of sound. The historical

flight was made as part of an event to celebrate the anniversary of Christopher Columbus’ discovery of America. Steve Fossett set the solo record in March 2005, piloting Virgin Atlantic’s GlobalFlyer. He flew almost 37,000 kilometres (22,991 miles) in just 67 hours and one minute without even stopping to refuel.

does sTaTic shoW The birTh of The uniVerse?

Funnily enough, the answer to this question is both yes and no. Yes, a certain amount of the ‘white noise’ you used to see when TV channels mistuned could be attributed to cosmic background radiation (CBR) – taken as some of the best proof we have of the Big Bang theory. However, other factors included in TV interference were sparks,

lightning and solar radiation. Since many countries have now completed the digital switchover and stopped broadcasting shows in analogue, TVs are unable to randomly pick up CBR through analogue interference. So you can no longer see some aspect of the origins of the universe from 13.8 billion years ago!

WhY are There hoLes in The oZone LaYer? like refrigerants and the propellant in aerosol cans. When released into the atmosphere these CFCs accumulate in the stratosphere. Cold temperatures over Antarctica cause the formation of polar vortices, which create highaltitude ice clouds. When the Sun’s light hits these clouds, the CFCs convert into a highly reactive form of chlorine that destroys ozone. While the holes diminish in size during the warmer months, every spring the ozone layer in both the Antarctic and Arctic regions shrinks. CFC pollutants have been greatly reduced, but it will take a long time for the CFCs to completely deteriorate.

Every spring over Antarctica, and to a lesser extent in the Arctic, the ozone layer thins so that ‘holes’ appear. While a normal oxygen molecule (O2) consists of two oxygen atoms, ozone (O3) has three. Most of the ozone in the stratosphere is created when powerful solar photons break the bonds inside O2 molecules, freeing individual oxygen atoms (O), which can then rejoin normal O2 atoms to create O3. The main offenders in the depletion of ozone are chlorofluorocarbons (CFCs), which are banned in many countries. These organic carbon, fluorine and chlorine compounds are produced by man-made substances

Ozone concentration

Take a look at how ozone is distributed through our planet’s atmosphere 100 –

Altitude (km)

80 –

60 –

Mesosphere 40 –

20 –

0

Stratosphere Troposphere 0

3

Ozone (parts per million)

6

9

do dead

sTars

shine in The sKY?

Astronomers talk of a star ‘shining’ only when it is generating energy within itself by nuclear fusion, but stars continue to shine in the normal sense, pumping out huge amounts of light and other radiation, long after their fuel is exhausted and fusion has come to an end. White dwarf stars have superhot surfaces with temperatures of 100,000 degrees Celsius or more, and blaze with a searing mix of white light, ultraviolet light and X-rays – they’re only faint because they’re so tiny. They continue to glow for many millions of years as they gradually cool and fade.

hoW does

WaTer

conducT eLecTriciTY?

The short answer is: pure water does not conduct electricity. Any impurities, like salts, in the water enable it to conduct electricity. When salts are dissolved in water, they separate into different electrically charged atoms called ions. Salt, or sodium chloride (NaCl), breaks up into positive Na ions and negative Cl ions. If you place a battery with a negative pole and a positive pole into water, the negative ions will be attracted to the positive pole and the positive ions will be attracted to the negative pole thus creating a closed circuit.

c i t c r a t n A e h Animals of t Orca are highly intelligent and , tors organised preda the putting them at tic rc top of the Anta food chain.

sWiPe for More

Wandering albatross

Elephant seal

At their best during rough weather, the albatross’s colossal wings can lock into place for effortless gliding on the wind.

These seals have more haemoglobin in their blood to carry more oxygen, enabling deeper and longer dives for food.

Killer whale

A thick layer of blubber sits beneath the whale’s skin to insulate and provide energy when food is scarce.

Minke whale

Minke whales leave the icy waters of Antarctica and head to the tropics to breed.

Sperm whale

These leviathans can hold their breath for up to 90 minutes on deep dives hunting for giant squid.

Crabeater seal

Despite their name, these seals feed on Antarctica’s rich supply of krill, using specially adapted teeth to filter the water.

Chinstrap penguin

Densely packed feathers that insulate and also provide a protective waterproof layer help to keep these small birds warm.

Black rock cod

As cold-blooded ectotherms, ice fish possess ‘antifreeze’ proteins in their blood that prevent them from freezing.

Gentoo penguin

Penguins are perfectly streamlined in the water, enabling them to be excellent fish hunters for sustaining energy reserves.

Emperor penguin

Four layers of specialised feathers, a plump body and plenty of huddling are just some of Antarctica’s emperors’ adaptations.

WhY is

rubber so sTreTchY? The stretchiness of rubber is down to its structure, and the law of entropy. Rubber is made from long chains, which in their relaxed state can be twisted and curled around each other in a huge number of different ways. As it is stretched, the chains straighten out and line up, forming an orderly structure. When the stress is removed, the strands want to return to a lower-energy disordered state, so they spring backward. In many types of rubber, the strands are joined together by chemical bonds that form cross links, fixing them into a flexible web and encouraging the material to spring back to a similar shape each time.

WhaT’s

The MosT

inVasiVe

PLanT? Several plants could claim this title, but the world’s worst water weed is undoubtedly the water hyacinth. Found in 50 countries on five continents, this free-floating South American plant can double in mass every five days. It forms dense mats which rapidly clog waterways, limit boat traffic and stop sunlight and oxygen reaching underwater. 50 million tons of water hyacinth are removed each year from the White Nile alone. This exotic plant can escape into the wild from ornamental ponds where it is prized for its beautiful purple-blue flowers and attractive shiny dark-green leaves.

Who WouLd Win in a fighT beTWeen a

hiPPo and a

rhino?

It would be a fairly close battle, which is probably why they almost never clash head to head in the wild. Both animals are highly territorial, but the hippo is much more aggressive. Fights between two male rhinos normally don’t amount to more than some horn clashing and a little urine

spraying. Male hippos, on the other hand, regularly inflict serious injuries on each other with their massive teeth. The rhino has an impressive charge, but in close combat the enormous gape of the hippopotamus’s mouth probably gives it the advantage over the long, unwieldy horn of the rhino.

hoW are boTTLes recYcLed? 1

COLLECTION

Your empty plastic bottle is collected and taken to a recycling facility for sorting. If you have already separated the plastic bottles from the rest of your recycling they can be sent straight to a recycling plant.

5

It is hand-checked to remove any non-recyclable material. It is loaded into a ‘trommel’, a large perforated spinning drum. Plastic bottles and cans are separated through the perforations, then steel and aluminium cans are removed using magnets and electromagnetic technology.

FLAKING

The melted plastic is reformed into flakes or pellets as it cools. These can then be melted down again and used to make new products. For example, the melted plastic can be reshaped into new plastic bottles, ready to be filled with a product.

2

1

2

5

275,000 tons

SEPARATING

3

4

500+ years How long plastic can take to decompose

Amount of plastic used in the UK per year

4

SHREDDING AND MELTING

Bottles are shredded and the shreds washed again to remove impurities, including remnants of paper labels or the bottle’s original contents. They may also be decontaminated further using a chemical solution. The shreds of plastic are then dried and melted down.

3

SORTING

The bottles are then cleaned and sorted by type and colour using infrared beams. The infrared light is reflected off the plastics in different ways, allowing a sensor to detect which is which. Precision jets of air then separate the different types.

3. Snap the remaining lead so it

lies across the two inserted leads, without touching the sides. Add some grooves to keep it in place.

Mini MicroPhone EQUIPMENT

Two pencil leads Pencil Scissors Matchbox 4.5-volt battery Earphones Three electrical leads with crocodile clip ends

1. Take a matchbox and empty it. Then with your pencil pierce two holes at either end, roughly 3cm (1in) apart halfway up. Ensure the holes line up with each other.

4. Take your electrical leads and

attach the clips so that the first lead goes from one of the box’s lead lines to the Variables battery, the second What happens if connects the battery to you add more leads the headphone jack and to the tray? Does the final one attaches this affect the the jack to the other lead sound? line in the matchbox. Once the circuit is completed, try talking into the box while a friend listens via the earphones.

WHAT HAVE YOU LEARNED?

2. Snap two of your pencil leads so they are

roughly 1cm longer than the tray and insert them through the holes. File down their tips with your pair of scissors to help.

When you speak into the matchbox, the leads vibrate, an action that pushes against the air hundreds of times per second. A series of high-pressure compressions and low-pressure rarefactions vary the electric current flowing through the leads from the battery. It is these variations in current that the earphones can convert back into sound.

The M1 drives like a car – it has a steering wheel and foot pedals, says Benson (some models use levers for forward and back). Peck says he knows of a gunner who sat comfortably during a Baghdad campaign for 75 hours straight.

2. COMFORTABLE SEATING

Benson says the M1 has the most advanced fire control system of any tank on the planet – the sensors, crosshair viewfinder, gun stabilisation, and rangefinding capability are second to none.

1. FIRE CONTROL SYSTEM

The chassis of the M1 is what makes the tank able to withstand abuse. Peck says M1 tanks can go through a re-build process three or four times, adding new digital components.

3. CHASSIS

The heavy tracks that propel the tank are made of a hard rubber with steel pins that hold it all together. Benson says the soldiers in the tank know how to quickly fix any track problems on the battlefield.

4. TWO-TON TRACKS

For more information about the M1 Abrams tank visit www.army-technology.com where you can read more about this destructive behemoth, as well as other lethal weapons used in 21st Century combat.

The M1 uses a turbine engine with 1,500 horsepower torque to push through heavy terrain. Benson, who served as a Commander, says the M1 can still get stuck, but it is rare.

5. POWERFUL TURBINE ENGINE

under The hood of The abraMs M1

F O Y M O T WITH RETIRED LT COLONEL KEVIN BENSON AND DESIGNER MIKE PECK: A AN

Illustrations © Alex Pang

HOW TO Learn abouT sound WaVes

1 PREPARE YOUR EXPERIMENT

Half-fill a glass with water and set it aside. Next, cut horizontally through a drinking straw around two-thirds of the way up. You want to be able to bend the smaller third at right angles without breaking the straw. Be prepared to have several goes at this before getting it right, as it is quite a delicate operation. Once you have successfully cut through the straw, place the larger part into the glass and bend the smaller part back.

3 PITCH UP

To take the experiment further, see how the pitch changes as you increase or decrease the volume of water in the glass. You should notice the pitch gets higher with more water in the glass. This is because the pitch of sound is determined by the speed of the vibrations. With more water in the glass, the straw is fuller and the vibrations have less time to stretch out. This increases the speed of the vibrations, making the sound that reaches your ear much higher.

2 MAKE SOME MUSIC

The smaller part of the straw should be bent so that when you blow through it, the airflow passes along the top of the straw. Blow gently into the tube. You should be able to hear a whistling sound. This sound is created as the air inside the larger part of the straw vibrates. The vibrating air travels down the straw, hits the water and bounces back up. Once out of the straw again, the sound waves expand, reaching your ear as a whistling noise.

IN SUMMARY…

This is an easy way for you to understand the properties of sound and how it can be manipulated. Sound comes from vibrations. By speeding them up or slowing them down, we make sounds higher or lower. This is something we do every day when we talk.

16 48 Survivors

706

Lifeboats required

Lifeboats launched ong wr ent cw ani Tit ere Wh

STATISTI COOL / People on board

2,223 Deaths

20 1,517 Lifeboats on board