For human beings breathable air consists of a ratio of oxygen to some inert gas (on earth it is nitrogen). The typical concentration is about 1/5th oxygen and 3/4 nitrogen.
Where does oxygen come from? Oxygen readily combines with so many different elements. Hydrogen + oxygen makes water. Carbon plus oxygen makes carbon dioxide. Iron plus oxygen makes rust. Silicon combines with oxygen to make sand. So free atmospheric oxygen is an oddity. Why do we have such an abundance of it?
This question brings us to lakes. More particularly, oceans. Earth's early oceans teemed with single celled organisms that absorbed carbon dioxide from the atmosphere or that was dissolved in sea water, and using sunlight broke that molecule apart, releasing the oxygen. After eons these photosynthetic creatures tore apart most of the atmospheric CO2, rendering it into carbon, which they absorbed and used, and releasing the oxygen.
After several billion years photosynthetic plants evolved, first in the oceans, and then migrating into the terrestrial sphere (land). But even today most new oxygen come from marine cyanobacteria, mostly in the ocean, but also in lakes and rivers, and to some extent pine needles, leaves on trees and bushes, blades of grass, and ferns.
The Bohr model helps us understand the way that quantum mechanics determines different energy levels for various atoms. However, the VSEPR (valence shell electron pair repulsion) model gives us a better understanding of how the outermost shell of electrons interact with each other (repelling each other maximally) to form bond angles.
The ballistics information for each bullet and cartridge. Hornady publishes data for ammunition derived from testing utilizing SAAMI (Sporting Arms and Ammunition Manufacturers Institute) specification test barrels.
It was Alfred Kinsey. He is the founder of the Kinsey institute for research in sex, gender and reproduction.
Organic matter convertible into heat, directly by burning or indirectly by biogastification
The melting point is 1220.58F. The boiling point is 4566F.
According to the newspaper account given by the link it was first prepared by Acharya P. C. Ray.
Eyeglasses refract light to correct for problems with the eyes. As the light needs to be bent more, the glass needs to be thicker to make the light bend farther.
The reading is not accurate if it is not in the liquid that you are measuring. Once you take it out, the temperature will be measuring the air.
Where is the deepest oceanic trench located
A variable is a characteristic in an experiment that is allowed to change. A constant, on the other hand, is a characteristic that is controlled or assumed to remain the same throughout a sampling or experiment.
For example, in determining the effect of a medication on a population, variables that can be considered are: age, preexisting disorders, gender, genetic history, etc..
The most species are probably in the ocean.
A bubble wrap bag has a wide variety of uses. Their primary use is to protect items whilst they are being transported, either in the post or in a home move. They can also be popped to release stress and for fun.
Bubble mailers consist of a strong puncture resistant mail bag with bubbles filled with air. Due to their specifics, bubble mailers are a very effective shipping material, protecting your products against the hazards of shipping.
They help regulate crucial body processes