The Hunter gatherer era essays

The Hunter gatherer era essays The Stone Age was a time early in the development of human cultures before the use of metals when tools and weapons were made of stone, and human food was mainly produced from hunting and gathering. The dates of the Stone Age vary considerably for different parts of the world and even until very recently there were some cultures that lived in much the same way as the hunter-gatherers of thousands of years ago. In the Stone Age, the hunting and gathering of food was the norm. The males of this time specialized in hunting - usually with stone-tipped weapons, while the females gathered items. Incidental tools were the first tools to be used. These tools were stones, sticks and other such items that the early humans found just lying about. Next came dawn stones the first stone tools to be fashioned. These were usually crudely chipped pebbles or flaked stone implements that were used for many purposes, but dawn stones also included the stone and anvil which was used for breaking bones open to get to the marrow deep inside. Over time, a wide variety of tools were made for many purposes. By about 100,000 years ago, humans already had several types of stone tools and were using bone and wood implements as well. As time went by, these modern humans (Homo sapiens) made such specialized tools as bone needles, bone fishhooks, nets, hand axes, choppers, scrapers, backed knives, burins, points, spears, and wooden bows Needles were used to sew animal skins together for clothing using sinews as the thread. Fishhooks and nets were used to catch fish. Hand-axes could be used for cutting meat, scraping skins, chopping wood, digging holes, and hammering bone or wood. Choppers were used for smashing bones open to obtain marrow, hacking wood, softening meat, and possibly as a primitive hammer. Scrapers were deployed for dressing hides and possibly obtaining meat from bones. ...

Atomic Number Definition - Chemistry Glossary

Atomic Number Definition - Chemistry Glossary The atomic number of a chemical element is the number of  protons in the nucleus of an atom of the  element. It is the charge number of the nucleus since neutrons carry no net electrical charge. The atomic number determines the identity of an element and many of its chemical properties. The modern periodic table is ordered by increasing atomic number. Atomic Number Examples The atomic number of hydrogen is 1; the atomic number of carbon is 6, and the atomic number of silver is 47, Any atom with 47 protons is an atom  of silver. Varying its number of neutrons changes its isotopes while changing the numbers of electrons makes it an ion. Also Known As: The atomic number is also known as the proton number. It may be represented by the capital letter Z. The use of capital letter Z comes from the German word Atomzahl, which means atomic number. Before the year 1915, the word Zahl (number) was used to describe an elements position on the periodic table. Relationship Between Atomic Number and Chemical Properties The reason the atomic number determines the chemical properties of an element is that the number of protons also determines the number of electrons in an electrically neutral atom. This, in turn, defines the electron configuration of the atom and the nature of its outermost or valence shell. The behavior of the valence shell determines how readily an atom will form chemical bonds and participate in chemical reactions. New Elements and Atomic Numbers At the time of this writing, elements with atomic numbers 1 through 118 have been identified. Scientists typically talk about discovering new elements with higher atomic numbers. Some researchers believe there may be an island of stability, where the configuration of protons and neutrons of superheavy atoms will be less susceptible to the quick radioactive decay seen in known heavy elements.