Why did Chemistry Become a Science?

Three Primary Factors Based on needs and wants Needs –Shelter from the elements –Food and water –Protection Wants –A mate –Improved self-image (status, beauty) –Entertainment Needs –Shelter from the elements –Food and water –Protection Wants –A mate –Improved self-image (status, beauty) –Entertainment

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

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)

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.

Apache Tears are obsidian, found in Superior

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

Agate (mostly quartz)

Fire was a huge advance in learning the chemistry of nature and improving chances of survival.

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

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.

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.

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.

Dirt became a solution with fires help 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.

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.

SiO 2 *2H 2 O AlO 3 *2H 2 O mullite: Al 6 Si 2 O 13 Temper

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.

Drying (dehydration) Accelerated evaporation with air and sun Absorption of water with salt

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.

H H O C C O C C H H H H H H H H H H O

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. CH 2 =CH-CH 2 -N=C=S

Epsom Salts- MgSO4 * 7H 2 O Plaster of Paris- CaSO4· 1/2 H 2 O

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

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

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

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

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.

C Cu O O

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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