Rapidly receding glaciers on Baffin Island reveal long covered Arctic landscapes

Rapidly receding glaciers on Baffin Island reveal long covered Arctic landscapes 

The study, published  today in the journal Nature Communications uses radiocarbon dating to determine the ages of plants collected at the edges of 30 ice caps on Baffin Island, west of Greenland.

The island has  experienced significant summertime warming in recent decades.

"The Arctic is currently warming two to three times faster than the rest of the globe, so naturally, glaciers and ice caps are going to react faster," said Simon Pendleton, lead author and a doctoral researcher in Cu Boulder's Institute of Arctic and Alpine Research.

Moon's craters reveal recent spike in outer space impacts on Earth.

Moon's craters reveal recent spike in outer  space impacts on Earth

It has long been thought that as the solar system grows older and stodgier, the number of comets colliding of earth and other planets has steadily gone down. But a new study reveals what appears to be a dramatic 2.5 times increase in the number of impacts striking  earth in the past 300 millions years.

Earth's surface is dotted with impact craters from the past billions years, but old craters are rarer than younger ones, a bias attributed to the crust - eating churn of plate tectonics, volcanic and erosion. But  looking at the moon which doesn't deal with the same forces but faces the same bombardment can probe the past of both bodies.

Non Equilibrium

Solutions

In solution chemistry and biochemistry the Gibbs free energy decrease is commonly used as a surrogate for the entropy produced by spontaneous chemical reactions is situations where there is no work being done; or at least no useful work, i.e., other than perhaps some ± P dV. The assertion that all spontaneous reactions have a negative is merely a restatement of the fundamental thermodynamic relation, giving it the physical dimensions of energy and somewhat obscuring its significance in terms entropy. When there is no useful work being done, it would be less misleading to use the Legendre transforms of the entropy appropriate for constant T, or for constant T and P the  Massive functions −F/T and −G/T respectively. 

Metals And Non Metals

Physical Properties of Metals And Non Metals

Have you ever observed a blacksmith beating an iron piece or an article made up of iron like a spade, a shovel, an axes, etc? Do you find a change in the shape of these articles on beating? Would you expect a similar change if we try to a wood log?
The property of metals by which they can be beaten into thin sheets is  called malleability.  The property of metal by which they can be drawn into wires is called ductility.
The metals that produce a sound on striking a hard surface are said to be sonorous.
The materials which are generally hard lustrous, malleable, ductile, sonorous and good conductor of electricity are called metals. Examples of metals are iron, copper, aluminium, magnesium etc.
The material like coal, sulphur are soft and dull in appearance, breakdown into powdery mess on tapping  with hammer, are not sonorous and are poor  conductor of heat and electricity. These material are called  non metals. Examples of non metal are sulphur, carbon, oxygen, phosphorus etc.

Plastics

You are aware of many  plastic articles used in our day- to - day life. Make a list of such items and their uses.
Plastic is another polymer like the synthetic fibers. Plastics have different type of arrangement of units. In some it is linear whereas in other it is crossed linked. Plastics are available in all possible shapes and sizes. The fact is that plastics are easily mountable, i.e. can be shaped in any form. Plastic can be recycled, reused, colored, melted, rolled into sheets or made into wires. That is why they                                                                                              find such a variety of uses.

Plastic Are Poor Conductors

Why there is a plastic covering around the electric wires? It is used because plastic is a poor conductor of electricity. Handles of trying pans, cookers etc. are made of plastic material because these are poor conductors of heat.

Synthetic Fibers

What Are Synthetic Fibers?

 Recall the uniform pattern found in a necklace of beads joined with  the help of a thread. Or, try  to join a number of paper clips together to make a long chain. There any similarity between the two? A synthetic fiber is also a chain of small units joined together. Each small unit is actually a chemical substance. Many such small units, combine to form a large single unit called a polymer. The word polymer has been derived from two Greek words. The word poly and mer. means 'many' and merstands for part/unit. So, a polymer is made up of many repeating units.

Homeopathy

What Is Homeopathy

Homeopathy is a medical system based on the belief that the body can cure itself. Those who practice it use tiny amounts of natural substances, like plants and minerals. They believe these stimulate the healing process.It was developed in the late 1700 in Germany. It’s common in many European countries, but it’s not quite as popular in the United States.

Chemical Affinity

Gibbs Function Or Gibbs Energy

For a "bulk" system they are the last remaining extensive variables. For an unstructured, homogeneous "bulk" system, there are still various extensive composition variables that G depends on, which specify the composition, the amounts of each chemical substances, expressed as the numbers of molecules present or the numbers of moles. 

The expression for dG is especially useful at constant T and P, conditions which are easy to achieve experimentally and which approximates the conditions in living creatures.

Chemical Energy

Chemical Energy

Chemical energy is the potential of a chemical substance to undergo a transformation through a chemical reaction or to transform other chemical substances. Making and breaking chemical bonds involves energy or heat, which may be either absorbed or evolved from a chemical system.

The energy that can be released because of a reaction between a set of chemical substances is equal to the difference between the energy content of the products and the reactant. This change in energy is called the change in internal energy of a chemical reaction.

The change in internal energy is a process which is equal to the heat change if it is measured under conditions of constant volume, as in a closed rigid container such as a bomb calorimeter. However, under conditions of constant pressure, as in reactions in vessels open to the atmosphere, the measured heat change is not always equal to the internal energy change, because of pressure-volume work also releases or absorbs energy. 

Another useful term is the heat of combustion, which is the energy released due to a combustion reaction and often applied in the study of fuels. 

Chemical thermodynamics

Chemical Thermodynamics

Chemical thermodynamics is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics. Chemical thermodynamics involves not only laboratory measurements of various thermodynamic properties, but also the application of mathematical methods to te study of chemical questions and the spontaneity of processes. the structure of chemical thermodynamics is based on the first two laws of thermodynamics. starting from the first and second laws of thermodynamics, four equations called the "fundamental equations of Gibbs". From these four, a multitude of equations, relating the thermodynamic properties of the thermodynamic system. This outline the mathematical framework of chemical thermodynamics.

Magnetic Field

Definition of Magnetic Field

A magnetic field is generated when electric charge carriers such as electrons move through space or within an electrical conductor. The geometric shapes of the magnetic flux lines produced by moving charge carriers (electric current) are similar to the shapes of the flux lines in an electrostatic field.  But there are differences in the ways electrostatic and magnetic fields interact with the environment.

Nitrogen

Nitrogen Fixation

Recall  the  bacteria Rhizome, Colostrum and Bacteriol that can fix  nitrogen present in the air. These bacteria are present in the root nodules of legumes such as bean and pea. Sometimes nitrogen gets fixed through the action of lightning. But you know that the concentration of nitrogen remains constant in the atmosphere. You may wonder how? Let us understand in next section.