How things work college course/Hunting the Elements (PBS NOVA)

Will do this after the quizzes for Fall 2015 have been completed.

Gold[edit | edit source]

{Au is the symbol for}
{All the gold ever mined would fit into a single cube of about}
{Gold is quite common in the Earth’s crust, but is difficult to mine because it is locked up in granite.}
{Although modern assaying methods yield more precise estimates, it is usually possible to estimate the quality of ore by counting the density of yellow specks in dirt from ore. }
{It is unusual to see the gold in gold ore with the naked eye}
{To assay gold ore is to }determine the quality of gold ore. purify it after it has been mined
{In ‘Hunting the Elements’, the gold ore from the Cortex mine is first crushed to the consistency of …Gravel sand baby power
{The fire assay process is ----- years old} 500
{What fraction by weight of typical gold ore contains actual gold} answer: 32,000 or equivalently 25 pounds per 400 tons
{About ____ % of the elements are metals} 75%
{ How an atom reacts chemically depends on how willing it is to share electrons with others } true
{ So do other so-called "noble" metals: silver, platinum, palladium,
{ Using cyanide to react with the gold allows them }
{ with a white powder called flux, chemicals that prevent the molten gold from reacting with or sticking to anything }

{ The ancients first learned how to heat rocks to extract copper, at least 7,000 years ago.}
future's market
Cu is coper
malleable
scares away bacteria
Tin is Sn
Tin plus copper is bronze
{When ‘Hunting the Elements’ visited the Verdin Company, they began the process with a bell, not of ______, but of ______. This bell was used to make a mould of }
{ first manmade metal .alloy was bronze }
{Which was first used, copper or bronze? }
{Copper is soft and easy to dent because ..The rows of atoms can easily slide past each other }
{What makes a metal conduct electricity?}
define ingot
An alloy of copper is made hard by the fact that the added atoms are …larger
In ‘Hunting the Elements’ it is speculated that the libergy bell cracked because of too many atoms other than coppermpurites
When the molten bronze is poured, what is done to prevent flaws from developing? (pour fast)
20-30% of molds fail

Boundaries between grains are actually defects in the orderly arrangement of the atoms. --Crystallite.jpg
In ‘Hunting the Elements’, Why would an electron microscope be covered on blankets
In ‘Hunting the Elements’, what could the electron microscope see? Atoms could be seen but not distinguished. (true, distractros include Innelectronsr and outer shell