Re: To any Engineer

>	
If everybody, every technology was destroyed and you were the 
>only one on the planet Earth, how would you survive? What would you 
>build in order to survive? How would you build them?

>
>	
I am asking you this question because in school, me and 64 other 7th 
>graders are playing a game where we are on the planet Earth and we are
>the only people inhabiting Earth (except for a few "tribes" here and 
>there), and we need to survive by reinventing the wheel, reinventing
>fire, making gunpowder, etc. We can have alliances or declare war against
>each other. Our teacher (the tribes-master) sees what we do and by


The game you describe sounds very interesting and fun.  A single
individual with a normal lifespan and no tools or technology could not
(realistically) get very far in rebuilding civilization.  But in the
spirit of the game, we'll stretch things a bit and consider some of the
important things you'll need.

The first things to take care of are the necessities: food, shelter, and
safety.  If you do a good job with these things, you'll have time to
work on more advanced problems.

FOOD

To keep food available, you need 1) a supply of food, 2) a way to access
that supply, 3) ways to store the food once you have it, and 4) tools to
prepare the food for eating.  Everything depends on what kind of food is
available.  Let's say you have access to wild animals for meat and
edible plants that can be cultivated.  To get at the food, you'll need
tools such as knives, axes, saws, and shovels in order to build roads
and bridges.  This requires a 1) supply of metal, 2) ways to access
(mine) the metal, 3) ways to store metal once you have it, and 4) tools
to prepare (forge and sharpen) the metal.

To store food, you'll need containers.  That means you'll want to be
able to create ceramic pottery.  Again, you'll need a supply of good
clay, ways of accessing the clay (roads, wheelbarrows), ways to store
the clay (moist containers), and tools to prepare (shape) the clay.  In
addition to containers, food storage also involves preservation.  The
simplest way to preserve meat is to salt it --- a supply of salt, ways
to mine salt from underground, plus containers to store it and use it
(soak meat in container of salt water).

If you've done all that, you'll have what you need to prepare the food.
Your knives will let you separate edible from non-edible parts of a
plant or animal.  Your ability to control and create fire (part of
forging metal into knives) lets you cook.

One of the best things you can do to insure a steady supply of food is
to grow it yourself.  This requires doing what it takes to allow farming
--- a supply of good seeds, tools to build irrigation (water supply) for
the seeds, tools to fertilize the ground where the seeds grow, and tools
to harvest the plants when they are ready to eat.

SHELTER

What kind of shelter you'll need will depend a lot on where you are.
Let's say you are in a temperate, mid-latitude climate like St. Louis.
To survive, you'll need to invent a whole bunch of things and solve a
wide range of problems.  If possible, you'll want a house that can last.
This means using durable materials such as wood, brick, or stone.  Let's
use wood.  You'll need all kinds of metal instruments to cut down the
wood, transport it, and make useful shapes out of it; metal nails or
something else to hold the wood together; oil to coat the wood and keep
it from rotting.  If you have roads, pottery, and the ability to shape
metal, this will all be a lot easier.

To keep the shelter warm in cold weather, you need to be able to start
and control a fire.  A stone fireplace should do.  To make a fireplace,
you can use clay bricks.  Just get the clay into the proper shape and
then heat it to a high temperature to make it dry and hard.  To start
fires, find a supply of flint which can be used to make sparks.
Eventually, it would be nice to find inflammable chemicals that make
fire starting easy.  

You also need to make the shelter as watertight as possible.  One way to
do that is to stretch animal hides across the roof.  Learning to turn
animal hides into a watertight roof (also clothing) is useful, but there
are better ways if you have the right materials.  

As you can probably tell from what I've said so far, having good
materials and good tools makes all the difference.  The other crucial
ingredient is cooperation from others (if you can get it).  In
particular, you can trade things.  Let's say, for example that you are
really good at building metal tools and someone else is really good at
getting wood.  Both are needed for a house.  So if you trade some of
your tools for some of this other person's lumber, you can both build a
house in less time than if you'd tried to do it by yourselves.  Trading
with others is just as important as building and inventing new things.

SAFETY

You need to be safe if you want to make progress on advanced projects;
if you're always being threatened, you'll never get anything done.  What
you need to be safe depends on what threats you have.  If the threats
are humans (or wild animals), you need to learn how to build walls and
weapons.  If disease and poison might be problems, you need to learn how
to dispose of waste, purify water, detect unclean or poisonous food, and
cure illnesses.  These are problems that you'll have to start out
handling in a crude way, and then get better at as time goes on.

ADVANCED PROJECTS

If you're on top of your food, shelter, and safety problems, perhaps you
might want to tackle more advanced things.  Here are some ideas and
inventions that have been especially important in history:

 -- Ship building.  Crucial for trade with others.  You'll have to learn
	to construct watertight hulls, large cloth sails, heavy metal
	anchors, rope, and plenty of other things.  If you want to
	travel long distances, you'll need to know your position.  The
	important inventions for this are: sextant, paper+ pencil, and..

 -- Clocks.  Clocks make all kinds of things possible including modern
	science and transportation.  Portable clocks let ships navigate
	over long distances

 -- Paper.  If you have paper, you can communicate more easily, spread
	ideas among members of a society, draw maps that make land and
	sea travel possible, and print money.

 -- Money.  The most important thing for a real, modern society is
	widespread cooperation and trade.  If people don't trade, they
	can't afford to spend time becoming experts because they'll have
	to learn about everything.  In small groups, people trade one
	item for another (barter); large groups use money.  Paper money
	is more convenient than metal or stone money.  

 -- Steam engine.  If you want machines, start with the steam engine.
	It's the simplest way of turning a fuel (wood is easy to find)
	into machine motion.  Once you have that, things like cars and
	planes will come quickly.


Good luck!