Features of the Scanning Tunneling Microscope

Posted by admin in Science on February 7, 2012

This scanning tunneling microscope (STM) invented by Heinrich Rohrer and Gerd Binnig in the 1980s still manages to do a great job today and competes with more advanced microscope types.

The scanning tunneling microscope is used for studying the surface atoms that are found on various materials. The device is based on a complex process of “tunneling” electrons between the material and the tip of a probe. The tip of the probe is sharp and extremely small and it allows for great precision. However, in order to get the best results, the distance between the tip and the studied material has to be precisely calculated. While the tip is moving on the surface of the material, a constant flow of electrons must be kept so as to get accurate readings. After the scanning tunneling microscope does its job, the researcher is left with a precise bump map of the surface material.

Classified as a scanning probe microscopy instrument, the STM is actually a better version of the atomic force microscope. The scanning tunneling microscope brings higher accuracy and better individual atom separation abilities, providing researchers with high resolution images. Since the size at which experiments can be done is very small (about 0.2 nm) the scanning tunneling microscope offers a lot of versatility in usage. By making the most out of the high resolution images, researchers can manipulate individual atoms on the material surface. This allows for precise chemical and physical reactions to be performed, as well as electron manipulation. Read the rest of this entry »

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Global Warming – A Threat To Mankind

Posted by admin in Global Warming on February 7, 2012

The world is currently witnessing an ecological threat called global warming. It is mainly caused due to the overall imbalance in nature. Global warming is most commonly referred to as the rise in temperature that is occurring everywhere around us and it is drastically causing changes in the climatic conditions. Almost every organism on the earth will be affected by the abnormal weather conditions.

Human beings conduct many activities that release gases such as carbon dioxide, methane, water vapor, nitrous oxide etc in excessive quantities. These gases, which are present in the atmosphere, absorb the sun’s heat and radiate the same thus keeping the atmosphere warm. There are innumerable sources that contribute to this problem. Chlorofluorocarbons are extremely harmful to the ozone layer and it mainly results due to the refrigeration and air conditioning that we use in our homes. The ozone layer encompasses the earth and it regulates the atmospheric temperature by entrapping the harmful ultraviolet rays.

One of the comprehensive effects of global warming is the quickening of the hydrogen cycle. It gives rise to many natural calamities such as droughts, floods or hurricanes. When the climatic condition turns intense, the microorganisms, insects or other harmful molds gradually multiply and therefore spread various diseases all over the landmasses. The crops wither out in the early stages due to the absence of essential minerals. Most of the living creatures will sooner or later be extinct if the hydrogen cycle continues to accelerate. Due to the acceleration, the marine life is deeply affected and the fishing industries may undergo crisis in the coming future. Read the rest of this entry »

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