Natural disasters

 

Natural disasters

Natural disasters are large-scale geological or meteorological events that have the potential to cause loss of life or property. These types of disasters include: tornadoes and severe storms, hurricanes and tropical storms, floods, wildfires, earthquakes, drought, avalanche, heat wave, landslide, tsunami, volcanic activity.

 Natural disaster, any calamitous occurrence generated by the effects of natural, rather than human-driven, phenomena that produces great loss of human life or destruction of the natural environment, private property, or public infrastructure. A natural disaster may be caused by weather and climate events or by earthquakes, landslides, and other occurrences that originate at Earth’s surface or within the planet itself. No spot on Earth is immune from a natural disaster; however, certain types of disasters are often limited to or occur more frequently in specific geographic regions.

In modern times, the divide between natural, human-made and human-accelerated disasters is quite difficult to draw. Human choices and activities like architecture, fire, resource management and climate change potentially play a role in causing natural disasters. A natural disaster is the highly harmful impact on a society or community following a natural hazard event. The term "disaster" itself is defined as follows: "Disasters are serious disruptions to the functioning of a community that exceed its capacity to cope using its own resources". Disasters can be caused by natural, man-made and technological hazards, as well as various factors that influence the exposure and vulnerability of a community. A natural disaster is the negative impact following an actual occurrence of natural hazard in the event that it significantly harms a community. An example of the distinction between a natural hazard and a disaster is that an earthquake is the hazard which caused the 1906 San Francisco earthquake disaster. A natural hazard is a natural phenomenon that might have a negative effect on humans and other animals, or the environment. Natural hazard events can be classified into two broad categories: geophysical and biological. Natural hazards can be provoked or affected by anthropogenic processes, e.g. land-use change, drainage and construction.

There are 18 natural hazards included in the National Risk Index of FEMA: avalanche, coastal flooding, cold wave, drought, earthquake, hail, heat wave, tropical cyclone, ice storm, landslide, lightning, riverine flooding, strong wind, tornado, tsunami, volcanic activity, wildfire, winter weather. In addition there are also tornados and dust storms. A natural disaster may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage.

 

Top 10 Natural Disasters

What Is Electrochemistry?

 Electrochemistry is the subdiscipline of Chemistry that deals with the study of the relationship between electrical energy and chemical changes. Chemical reactions that involve the input or generation of electric currents are called electrochemical reactions. Such reactions are broadly classified into two categories:

Download Complete Chapter Notes of Electrochemistry

1. Production of chemical change by electrical energy, i.e., the phenomenon of electrolysis
2. Conversion of chemical energy into electrical energy, i.e., the generation of electricity by spontaneous redox reactions.

Electricity can be produced when electrons move from one element to another in certain types of reactions (such as redox reactions). Typically, electrochemistry deals with the overall reactions when multiple redox reactions occur simultaneously, connected via some external electric current and a suitable electrolyte. In other words, electrochemistry is also concerned with chemical phenomena that involve charge separation (as seen commonly in liquids such as solutions). The dissociation of charge often involves charge transfer that occurs homogeneously or heterogeneously between different chemical species.

Electrochemical Cell

A spontaneous chemical process is one which can take place on its own, and in such a process, the Gibbs free energy of a system decreases. In electrochemistry, spontaneous reaction (redox reaction) results in the conversion of chemical energy into electrical energy. The reverse process is also possible where a non-spontaneous chemical reaction occurs by supplying electricity. These interconversions are carried out in equipment called an electrochemical cell.

Types of Electrochemical Cell

Electrochemical cells are of two types: galvanic cells and electrolytic cells

Galvanic Cell

The galvanic cell converts chemical energy into electrical energy, i.e., electricity can be obtained with the help of a redox reaction. The oxidation and reduction take place in two separate compartments. Each compartment consists of an electrolyte solution and a metallic conductor, which acts as an electrode. The compartment containing the electrode and the solution of the electrolyte is called half cells.