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Shelter made from pine tree branches

Technology apocalypse: could we start again from scratch?

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Imagine waking up in a world in which all your creature-comfort technology has been wiped off the face of the planet. How would you go about putting it all back together? Here are eight fundamental starting points.

Armageddon or the apocalypse, the end of the world as we know it. Whatever the disaster, whatever the reason, you’ve awakened on the technology equivalent of Robinson Crusoe’s desert island. And just as the shipwreck victim had to start from first principles – building shelter, finding food, finding his way around – so do you.

You’re much worse off than our early-18th-century mariner, because you’ve dropped out of the post-Industrial Revolution age in which grid power, mains water supply, wireless telecoms, digital mapping, motorised vehicles and smart cities are just a few of the technologies you’ve taken for granted.

However, unlike Crusoe – that story is true by the way, being based on the survival of real-life castaway Alexander Selkirk – you have one major advantage. And that is you are technology-literate, engineering-savvy and just itching to get started on rebuilding the world as you once knew it. There are even a few rudimentary tools, such as an axe, a saw and a hammer to set you on your way. In your pocket you find a lighter, so creating fire is no problem. The fact remains, as night falls, you are well and truly up a certain creek without the necessary means of propulsion. So what do you do?

Magnetic compass

Although longer journeys requiring detailed navigation might not be an immediate priority in your post-apocalyptic world, it’s always useful to be able to determine the cardinal points (north, south, west, east). Although you’ll be able to reach some sort of approximation of them during the day by extrapolating from the position of the sun, or by night from the star Polaris that marks the celestial north pole, you really will need a rudimentary compass to get a reliable steer on magnetic north. Luckily, they’re easy to make.

What you need: A pointer made of a ferrous metal (such as an iron nail), a lodestone, a bowl of water and a cork.

Method: Transform your nail into a temporary magnet by repeatedly stroking it against the lodestone (magnetite is a naturally occurring magnetic mineral). Insert nail through cork so that it floats freely on the surface of your bowl of water. Providing there is no local interference from other magnetic sources, the nail will point to the magnetic north pole.

Reboot evaluator: Congratulations, you have invented the magnetic compass. Knowing where magnetic north lies is the (almost) perfect way to find your way around. The only drawback is that the magnetic north pole ‘wanders’ from ‘true north’ (the direction of the geographic north pole, ie 90° north), the difference between the two being the ‘declination’. But if you just want a reliable and reasonably accurate approximation, your ‘nail compass’ is the way forward.

Wheel and axle

We’re all familiar with the idea of breakthrough inventions being the ‘best since the wheel’. But the problem for our post-apocalyptic castaway is that you don’t have even a wheel. And you really need one because without the ‘mechanical advantage’ or ‘force amplification’ brought by the wheel and axle, you’re going to be stuck in a world where you simply drag everything around. The wheel is one of the classical ‘six simple machines’ defined by Renaissance scientists (the other five being level, pulley, inclined plane, wedge and screw) and at some point, in order to get out of your neo-Dark Age, you’re going to need them all.

What you need: A solid disc (such as a section out of a tree trunk), a chisel, a tree trunk.

Method: Once you’ve sawn off your round section of a tree trunk, find its centre (do this with simple geometry by drawing a chord at any point across it, find the midpoint of the chord and drawing a line at 90° to the chord – this will run through the centre. Repeat process and the intersection of the perpendicular lines is the centre). Chisel out a hole with a diameter slightly larger than your tree trunk. You now have your machine.

Reboot evaluator: The wheel and axle is fine as far as it goes, but without a connected platform it isn’t going to be much of an improvement on using rolling cylinders such as tree trunks and you won’t be able to fully exploit the mechanical advantage.


If you want to know how long something takes then you need a water clock, a simple device in which a known quantity of water flows out of a vessel at a regulated speed. These are called clepsydra and are the oldest known time-measuring instruments. But if you want to know what time of day it is, it becomes more complicated, which is where sundials come in. Working from the apparent position of the sun, it casts a shadow via an indicator (or gnomon) onto a plate of hour-lines.

What you need: A flat horizontal surface, a stick (for the gnomon), chalk.

Method: On the face of it, making a sundial is no more complicated than planting a stick in an open space where there is plenty of sunlight. But to achieve anything like accuracy you need to know precisely the vertical direction (make a plumb-bob from a piece of string and a stone) and true north (use your compass). You can then calibrate your hour-lines using your clepsydra and make them on your flat surface using your chalk. It also helps to know your local latitude and whether you need to compensate for factors such as daylight saving.

Reboot evaluator: Providing others have access to a similarly calibrated sundial and they are not too geographically remote from you, and there are clear skies in both locations, you’ll have a reasonable chance of being able to meet them at an agreed time (“...when the shadow is on the third line…”). But your sundial won’t be much use for timing, say, the boiling of an egg. For that you’ll need your water-clock.

Survival shelter

Assuming the very worst and there are no buildings of any description left, at some point you’re going to need to learn the rudiments of construction in order to provide protection and comfort. But as nightfall approaches, a little higher up the list is survival and, if you can’t find a dry cave, you’ll need to make an improvised survival shelter from natural materials. The three key elements to your proto-building are cover, waterproofing and insulation. This last consideration is the most important as most people who perish aren’t victims of starvation or dehydration, but exposure.

What you need: An axe, a tree, bracken, dried leaves.

Method: The best way to make an improvised shelter is to head for the woods, where there will be various options. The most basic shelter to survive the night is simply to make as big a pile of dry leaves as possible (at least 1m high) to make a ‘cocoon’ – a naturally insulated sleeping bag to burrow into. Make sure the area is dry underfoot. If there is more time, the ‘fallen tree’ method is better, though labour intensive. For optimal results, use your axe to cut into a young tree a few metres above ground so that the trunk can be hinged to the horizontal. The branches will then provide a frame for layers of waterproofing and insulation in the form of fern fronds and dried leaves.

Reboot evaluator: Your woodland shelter has literally saved your life and you’ve acquired construction skills along the way. But a survival shelter is just that, and constructing a more permanent hut will become a priority. Then pretty soon, armed with your knowledge of simple and compound machines, you’ll probably have your sights on building your own Stone Henge.


Because you come from a world of wireless digital communication, sending messages to other people will be one of your biggest headaches, due to the fact that your post-electricity-age brain will find it difficult to conceive of a system that is not device-based. But given that even the most rudimentary incarnation of technology-based communication – telecommunication – was developed less than two centuries ago, there must have been sophisticated systems for transmitting long-distance messages. In fact, there were plenty: from the earliest talking drums in Africa and smoke signals in China and North America, to sophisticated optical telegraphs (flag semaphore, heliograph etc) to carrier pigeons. Let’s start with smoke signals...

What you need: Fire-starting technology, smoke-creating fuel, a wet blanket.

Method: Because your signals will be rudimentary to say the least – puffs of smoke rising into the air – it is vital that you agree in advance with your recipient what the resulting sequences will mean. A standard set of codes used by the Apache Native American tribes was one puff for attention or “something unusual, but no cause for alarm”, two puffs for “camp established and safe, staying here until further notice”, and three for “alarm, great danger” or an appeal for help. To create the puffs, head to high ground and simply light a smoke-creating fire (damp grass or wet leaves should work well) before punctuating the rising smoke with the use of the wet blanket.

Reboot evaluator: You are now in the connected world where the only limiting factors are the weather, the proximity of your recipient and the complexity of your agreed code. Don’t forget that your message can be ‘retweeted’ by your recipient for further distribution of your broadcast. The downside is also its upside, which is that due to the intricacy of the process it is best kept for important messages.

Compound machine: wheelbarrow

One-wheeled carts or wheelbarrows have existed since the time of the Ancient Greeks, who were quick to work out their potential for efficiently moving loads far greater than humans can easily carry. As such, they are among the earliest wheeled vehicles. The wheelbarrow is a ‘compound machine’ made up of two simple machines: the wheel and axle, and lever (the lever is of the ‘second class’ variety, or a ‘force multiplier’, in which the effort is applied on one side of the resistance and the fulcrum is on the other). Raising the handles creates an inclined plane. They have remained largely unchanged throughout history, until James Dyson came up with his ‘ballbarrow’ in the late 20th century.

What you need: One wheel and axle, chisel and saw, several planks of wood.

Method: The name gives it away. It’s a ‘barrow’ attached to a wheel. First construct your barrow (an old English word meaning ‘load-carrying container’) out of sawn planks, to which you attach two long braces, one each side of the barrow, protruding at the ends. These will be the handles (effort arms) and wheel mount (resistance arms). Chisel holes in the front end of both braces and attach wheel and axle subassembly.

Reboot evaluator: Now we’re getting somewhere. Your agriculture and construction efforts will now go much more smoothly. Gone are the days of carrying small loads by hand, replaced by up to 100 litres (3.53 cubic feet) capacity.

Energy: batteries

One of the first things you’ll notice in your brave new world is that there is no electrical grid. All the gadgets you’ve taken for granted will be literally powerless, unless you can find a way of generating your own electricity. Despite the fact that modern power systems are hugely complicated, if you get to grips with how basic primary (ie non-rechargeable) batteries work – this knowledge goes two millennia to the ‘Baghdad battery’ – you could end up with enough electric current to light up an LED (if you have an LED), by lashing together three components (cathode, anode and electrolyte) that are just lying around. Best to start modestly with a ‘lemon battery’, which will put you on the path beaten by the inventor of the modern electrical battery Alessandro Volta in the late 18th century.

What you need: Two different metals for the electrodes (cathode and anode) – a nail (zinc) and a coin (copper) should do the trick; two clip leads, and, of course, a lemon to supply the electrolyte.

Method: Partially squash your lemon to free up juices inside. Make two incisions in the lemon about 2cm apart. Insert nail and coin into incisions. Connect nail and coin to the LED terminals.

Reboot evaluator: You now have a device that can power another device, so you are a step down the road to recharging your smartphone. You’ve got a long way to go before your lemon battery does anything other than demonstrate the redox (reduction-oxidation) chemical reaction.

Transport: boat

You’ll need to explore your surroundings in search of resources, to make contact with humans and eventually establish trade routes. One of your modes of transport will be a boat. Both history and archaeology suggest that the earliest and simplest form of watercraft is the dugout or ‘monoxylon’ (from the Greek meaning ‘single tree’), which requires fewer engineering skills, equipment and materials to construct than its evolutionary successor, the raft. As dugout canoes tend to roll along their longitudinal axis, a stabilising technology worth considering is an outrigger, which is an item of ‘float rigging’ mounted outside the gunwale parallel to the main hull to prevent capsizing.

What you need: A log of light, strong, rot-resistant wood (cedar, spruce or pine are perfect) for main hull, a fire, an adze, rope (optional), additional wood for outriggers, paddles etc.

Method: First fell your tree and remove all extraneous features to create log. Remove internal material with an adze to create the hollow crew and cargo section. You can also remove the interior by lighting carefully controlled fires to burn unwanted material and then removing the burned log core with stone wedges (this will take much more time). For a wider hull section, the wood can be heated with steam and formed to create more space. Get your canoe into the water as soon as possible to prevent it from cracking.

Reboot evaluator: Your dugout scores heavily on its simplicity of design and construction, but falls down on the amount of time and labour required to make one. As dugouts routinely weigh more than 300kg, it’s unlikely you’ll be able to make and launch one without help.


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