Why did Chemistry Become a Science

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Why did Chemistry Become a Science?
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Three Primary FactorsBased on needs and wants

• Needs
• Shelter from the elements
• Food and water
• Protection
• Wants
• A mate
• Improved self-image (status, beauty)
• Entertainment

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NEEDS
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Extreme competition for food
Getting it
Keeping it
Not becoming food yourself
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Humans had a many disadvantages Many animals
were Bigger Faster Stronger Had sharper
teeth Had tougher skin Had better vision Had
better sense of smell
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STONE TOOL TECHNOLOGY
OUR OWN TEETH
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Knowledge of Rocks

• Knowing what kind of rocks that were good for
  making stone tools was critical for survival.
• Flint knapping is the art and knowledge of
  turning stones into tools. (Our wrists are
  suitable for this)

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Obsidian

• Near volcanoes, if the melted rock is mostly
  silica, it can form a natural glass called
  obsidian.
• It can be worked into very sharp tools.
• Even today some surgeons use obsidian knives in
  eye surgery.

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Obsidian
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Stone tools technology

• Amazingly, stone tools can be sharper than the
  surgical knives used today.
• Knives used for cutting meat, cutting hides,
  cutting fibrous materials.
• Axes used for chopping trees.
• Arrowheads for killing animals at distance.
• All could be used for self-protection

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Agate (mostly quartz)
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Agate mortar pestles
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HUNTING AND GATHERING OF FOOD
FOOD WATER STORAGE
Store food and water for times of shortage
Protect it against the weather and pests
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How do you store food and water?
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• Fire was a huge advance in learning the chemistry
  of nature and improving chances of survival.

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• If you want fire, you had to hope for a lightning
  strike to start it. Then you had to keep it
  burning.

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• Learning that fire had important uses.
• Warmth
• Softens food and makes it easier to digest
• Makes food safer to eat.
• Scares away predators.
• It causes changes in materials that are placed in
  the fire.

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Creation of Fire

• Figuring out how to start a fire without
  lightning was another huge step in chemistry.
• Friction- spinning a suitable stick on a suitable
  surface with suitable fuel. Learning which of
  these work best meant the mastering of fire.

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Survival with Fire

• Tribes who mastered the creation of fire had much
  better chances as survival than those who didnt.
• Even Tom Hanks in Castaway realized the
  importance of creating a fire.

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Dirt became a solution with fires help
The problem of food water storage

• Once you had fire where ever you wanted,
  primitive man would naturally try throwing things
  into the fire. Sometimes unexpected things
  happened.
• Sometimes certain dirt that normally would turn
  to mud when it got wet, would no longer turn to
  mud, if it had gotten subjected to fire.
• Dirt that could do this was pretty easy to
  recognize. After rains, and after the ground
  dried. This special dirt had cracks in it.
• Also, this special dirt could be shaped when it
  got wet. It was great for making figurines of
  animals and of beings that possessed special
  powers.
• But most important was that it could be molded
  into pots to store and protect food and water.

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CLAY
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Firing of Clay

• This special dirt is know as clay. Clay can be
  molded into a bowl and dried but if you added
  water to the bowl, it would become soft and weak
  and the water would leak out.
• However, if it gets subjected to fire, something
  very useful happens. It is no longer vulnerable
  to water and will hold its shape.

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Quartz
Silicon and oxygen atoms stacked tightly
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SiO22H2O
AlO32H2O
mullite Al6Si2O13
Temper
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Store food in a way to protect it against the
weather and pests
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Later glass blowing helped civilizations in the
storage of food drink
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PRESERVATION OF FOOD
Create environment that inhibits spoilage
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PRESERVATION OF FOOD
Create environment that inhibits bacteria growth
Cooking Sterilizes Dries Drying
(dehydration) Accelerated evaporation with air
and sun Absorption of water with salt Controlled
fermentation Wine (alcohol content prevents
bacterial growth) Distillation to increase
alcohol concentration Beer Cheese Separation of
oils, which last longer when separated Add
ingredients that prevent bacteria growth. Now we
can freeze, refrigerate, freeze dry, irradiate.
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Cooking
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Drying
Beef Jerky
Drying (dehydration) Accelerated evaporation
with air and sun Absorption of water with salt
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Controlled fermentation and separation
Yeast
alcohol
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VINEGAR
The bacterium, Acetobacter, converts alcohol to
acetic acid (vinegar). Oxygen encourages its
growth, highlighting the importance of excluding
oxygen during the wine making process. Mother
of Vinegar A slimy, gummy substance made up of
various bacteria specifically mycoderma aceti
that causes fermentation in wine and turns it
into vinegar.
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Ethanol (drinking alcohol)
Acetic acid (vinegar)
O
O
H
H
C
C
H
O
H
H
H
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Vinegar inhibits bacteria growth
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Peppers and chilis inhibit bacteria growth
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Even in Middle-Age Europe, it was well-known that
spices provide important preservation
qualities. The most effective antimicrobial
spices include garlic, onion, cinnamon, cloves,
thyme and sage. Cloves, which have a high
essential oil content, contain eugenol also
present in sage and cinnamon. Allicin, present in
garlic, also acts as an antimicrobial agent, as
does the allyl isothiocyanate present in mustard.
Thymol, present in thyme, oregano and sage, is
also noted for its antimicrobial properties.
  Research at Kansas State University,
Manhattan, has shown that cloves have a high
antimicrobial effect against E. coli in ground
meat. Cinnamon, garlic, oregano and sage were
also shown to be effective.
Spices inhibit
bacteria growth
CH2CH-CH2-NCS
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SOYBEANS
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Interferes with digestion
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Tofu
Precipitation
Soy Sauce
Epsom Salts- MgSO4 7H2O Plaster of Paris-
CaSO4 1/2 H2O
Fermentation
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Salt water
Fermentation
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Food The earliest use of chemistry
What foods were safe to eat?
What could be done to make food safe?
How could food be stored?
How to keep food from spoiling?
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More Needs and Wants
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Fire and the birth of the bronze age

• Usually you want a fire, but sometimes you want
  to put it out perhaps to hide your location or to
  prevent a brush or forest fire

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• Somewhere in the Andes thousands of years ago,
  the Peruvian Indians must have thrown some dirt
  over a fire to put in out.

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• The dirt actually was made of a high
  concentration of copper ore.

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• Returning to the fire later, instead of the usual
  gray ashes, a substance with a beautiful new
  color and miraculous qualities appeared.

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Copper is start of Bronze Age

• Other people around the world must have
  accidentally done the same thing. They didnt
  know the turquoise colored dirt was copper ore
  which is copper oxide (CuO). Nor did they know
  that the glowing embers was mostly carbon. At
  the temperatures of a campfire carbon in the
  embers can pull the oxygen away from the copper
  oxide to produce carbon dioxide leaving metallic
  copper behind.

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Cu
O
Cu
O
C
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Copper

• Copper could be bent into useful shapes like
  needles, fasteners, nails, and weapons.
• Copper couldnt be made as sharp as stone tools,
  but it was lighter and could be worked into a
  sword. It also could be shaped into armor.

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Copper

• Our ancestors didnt know the chemistry at that
  level but they did learn what copper ore looked
  like and that by heating it with red hot charcoal
  a copper metal would be produced.
• Copper was not a strong as stone tools, but it
  didnt break so easily. It also could be molded
  and bent into useful shapes.
• The mining of copper ore and the process of
  turning it to metallic copper (smelting) became
  an important industry.

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Swords

• A stone ax was a formidable weapon but it was
  heavy and only the end of it was dangerous.
• A sword is dangerous from the tip to the handle
  and because it is lighter it could be swung much
  faster.
• A good swordsman could usually defeat someone
  that had a stone ax.

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Bronze Age

• As you might guess, if a valuable metal like
  copper was produced by throwing a particular
  colored mineral into the fire, people would have
  tried throwing other types of minerals into the
  fire and checking the results.
• All metals except for gold is bound with oxygen.
  Oxygen likes to react with things and pure metals
  are eventually attacked by oxygen to form the
  oxide. The oxide of tin (tin ore) finally got
  thrown into the fire and metallic tin was
  produced. Tin was soft and not as useful as
  copper however, if it was mixed with copper and
  remelted, a new substance was created. It was
  call bronze. Bronze was stronger than tin or
  copper and resisted corrosion to water or salt
  water much better than copper. This became the
  metal of choice for the metal used on boats.

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Bronze swords

• Bronze swords would break copper swords.
  Therefore a civilization that mastered the
  chemistry of mining both tin and copper and
  understanding the metallurgy of combining them to
  produce the best alloy would have the best
  equipped army.

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Iron ore

• Iron ore is pretty easy to recognize because of
  its red color. It was thrown onto hot coals too
  but no new metal was produced.

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Iron Age

• Those who were building furnace to heat the ore
  and charcoal discovered that extra air (oxygen)
  would make the fire and furnace hotter.
• Some built their furnaces on a hill or a place
  where the winds blew. This created hotter fires.
• Some built bellows that could pump oxygen into
  the fire and create higher temperatures.
• When the red soil (iron oxide) was placed into
  these furnaces, a new metal was discovered.

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Iron Age

• Iron ore was more plentiful than tin or copper
  ores. Iron would corrode more than bronze but
  iron was stronger.
• Being more plentiful allowed iron to become more
  common place. Kettles, door hinges, wagon parts,
  and other useful utensils were made from it.
• Civilizations that could mine iron and create
  armour, swords, and cannons made from it, would
  be the ones that would survive conflicts.

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Blacksmiths

• The abundance of iron also created a new category
  of craftsmen known as blacksmiths. They had the
  tools and knowledge to forge and work iron into a
  multitude of useful and strong items. From
  nails, horseshoes, swords, anchors, and hundreds
  of things.

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Not all iron is the same

• The amount of impurities in the iron would
  contribute to its qualities. Better processes in
  purifying was important.
• It was discovered that repeated heating,
  hammering, and cooling of iron made it less
  brittle. Tempered steel. This was especially
  important for swords.
• Damascus steel.

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Weaponry

• Its unfortunate, but the sophistication of a
  civilizations weaponry seems to be the largest
  factor for its survival.