Give any two medical uses of oxygen

   In cells, oxygen is needed for aerobic respiration, which allows for the extraction of energy from ingested foods. Thus supplemental oxygen at home and in hospitals is vital for those with breathing disorders such as emphysema.

   Compressed oxygen tanks are used by mountaineers at high elevations to counteract the decreased O2 pressure at these altitudes.

   Supplemental oxygen is needed for surgical patients intentionally rendered paralyzed for medical procedures, in which "heart-lung machines" keep their vital functions going.

   Oxygen can be used as a sterilizing agent to kill certain anaerobic bacteria that are killed by sufficient exposure to the gas.

Industrial Uses of Oxygen:

   Oxygen is needed for the reaction that converts carbon to carbon dioxide gas in steel working, which takes place under high temperatures in a blast furnace. The carbon dioxide produced allows for the reduction of iron oxides into more pure iron compounds.

   Oxygen is used in other applications involving metal and requiring high temperatures, such as welding torches.

Aerospace Uses of Oxygen:

   In liquid form, oxygen is used widely as an oxidizing agent for use in missiles and rockets, where it reacts with liquid hydrogen to produce the terrific thrust needed for take-off. Astronaut spacesuits include a nearly pure form of oxygen.

   Oxygen is used to degrade hydrocarbon compounds, which are broken apart by heating them. This is used to create combustion that usually liberates water and carbon dioxide, but can also produce the hydrocarbons acetylene, propylene and ethylene.

   Oxygen is used in sewage-treatment and water-purification plants. It is forced through water to increase the production of bacteria that metabolize waste products in the water.

   Oxygen gas (O2) is needed to produce energy in things not linked to an electrical supply of their own, such as generators and vehicles (e.g., ships, airplanes and cars).

from almost the creation of the first true maps of the earth, people started seeing how continents would be able to fit together.   in particular, people noticed that south america fits almost exactly into africa.

you should be aware that while world maps were around early in the 1600’s and better defined by the end of the 1700’s, those maps were not ‘public’ but were treated as state secrets.   and so it was not till much later that the broader ‘science’ community had access to good quality and accurate world maps.

get the whole story here…

it is now known that most of the major continental masses can be fit together in a jigsaw process.   in fact we now know that the continents were indeed once all joined together as one land mass – the supercontinent of pangaea.

if you look at most world maps you will ponder how this is evidence, as the continents really don’t appear to ‘fit’ together very well.   what you need to understand is that the vast majority of maps are drawn using a map projection that has the north and south poles (which are points) are a line the width of the map at the top and bottom.   this means that the map distorts the true shape of the earth’s land and oceans as you love closer to the poles.     some other map projections distort less, but have the map shape looking like segments of an orange.   see here for a range of map projections.   check out the way greenland changes size in each!

what is more remarkable, is the next piece of evidence when added to the shape of continents.

location of mountains and fossils

what is remarkable, when you reassemble all the continents together, the ancient mountain ranges (many now eroded to their cores) and the location of rock types and fossils all match up.