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

• Shelter from the elements
• Food and water
• Protection

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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
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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 mortar pestles
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HUNTING AND GATHERING OF FOOD
PRESERVATION OF FOOD
Store food for times of shortage
Protect it against the weather and pests
Prevent spoilage
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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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