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Landslide

A landslide includes a wide range of ground movements, such as rock falls, deep failure of slopes and shallow debris flows. The biggest reason for a landslide is that there is a slope and material goes down the slope because of gravity. But other ...

                                               

Mercalli intensity scale

The Mercalli intensity scale is a scale to measure the intensity of earthquakes. Unlike with the Richter scale, the Mercalli scale does not take into account energy of an earthquake directly. Rather, they classify earthquakes by the effects they ...

                                               

Metamorphism

Metamorphism, in geology, is the change of the structure, texture, or composition of rocks. The scientific study of rocks is called petrology. Rocks are commonly divided, according to their origin, into three major classes - Igneous, sedimentary, ...

                                               

Mineralization

Mineralization may mean: In palaeontology: the process where organic material is converted to inorganic substance. Waterborne minerals replace organic material in the body of an organism that has died and was buried by sediments. The minerals may ...

                                               

Oil sands

Oil sands, or tar sands are an unconventional source of petroleum. The oil sands are a mixture of sand, clay and water together with a dense and extremely sticky form of petroleum referred to as bitumen. Natural bitumen is found in many countries ...

                                               

Palaeoclimatology

Palaeoclimatology is the study of changes in climate over the entire history of Earth. Modern interest in climate change has caused a great increase in the climates of the past. The climates of the past can only be studied by proxy. Data is got f ...

                                               

Quicksand

Quicksand is a mixture of water sand or silt. It has the characteristic of thixotropy: it looks solid, but when pressure is applied it liquifies. If animals or people stand on it, they sink into it. However, a person does not drown in quicksand. ...

                                               

Rock cycle

The rock cycle is the process by which rocks of one kind change into rocks of another kind. There are three main kinds of rocks: igneous rock, metamorphic rock, and sedimentary rock. Each of these rocks can change into the other kinds by physical ...

                                               

Salt evaporation pond

A Salt evaporation pond is a man-made shallow pond. Usually it is located near the sea. The ponds can be filled with salt water. The water is then left to evaporate. The salt is left behind, and can be harvested. Such ponds also provide a habitat ...

                                               

Sand

Sand is a mixture of very small pieces of different rocks or minerals. It is the same minerals from which those pieces are broken, such as granite and feldspar. Sand is gritty to touch. It is a naturally occurring granular material composed of fi ...

                                               

Seismology

Seismology is the study of what is under the surface of the Earth by measuring vibrations on the Earths surface. A person who does this is called a seismologist. It is part of the science of geophysics, which studies the physics of the processes ...

                                               

Silicate

In chemistry, a silicate is a chemical compound consisting of one or more central silicon atoms that are surrounded by electronegative anions. The most common silicate species consist of silicon with oxygen as the anion. Silicate anions, with a n ...

                                               

Silt

Silt is soil or rock that developed from granular material of a specific grain size. Silty soil has much smaller particles than sandy soil so it’s smooth to the touch. When moistened, it’s soapy slick. When you roll it between your fingers, dirt ...

                                               

Soil

Soil is loose material which lies on top of the land. It has many things in it, like tiny grains of rock, minerals, water and air. Soil also has living things and dead things in it: "organic matter". Soil is important for life on Earth. Because s ...

                                               

Strata

Strata are layers of rock, or sometimes soil. In nature, strata come in many layers. It is a term in sedimentary and historical geology; the singular is stratum. The study of strata is called stratigraphy. These layers are laid down as sediment, ...

                                               

Synthetic fuel

A synthetic fuel is a fuel in liquid or gas form that can be manufactured. Synfuels have long been made from coal. Oil extracted from shale or tar sands is also sometimes called synfuel. Fuels can also be made from non-food crops. Tar sands are a ...

                                               

Trace element

A trace element is present in only a small amount. The amount depends on context. In analytical chemistry, it is an element in a sample that has an average concentration of less than 100 parts per million ppm measured in atomic count, or less tha ...

                                               

Varve

A varve is a pattern in sediment which is made by annual processes. Varves are amongst the smallest-scale events in stratigraphy. They form only in fresh or brackish water. Varves are important in palynology, and can be fossilized as rhythmites. ...

                                               

Physics

Physics is a branch of science. It is one of the most fundamental scientific disciplines. The main goal of physics is to explain how things move in space and time and understand how the universe behaves. It studies matter, forces and their effect ...

                                               

4D

4D, meaning the 4 common dimensions, is an important idea in physics referring to three-dimensional space, which adds the dimension of time to the spatial dimensions of length, width, and depth. In geometry, the fourth dimension is related to the ...

                                               

Acceleration due to gravity

The acceleration which is gained by an object because of gravitational force is called its acceleration due to gravity. Its SI unit is m/s 2. Acceleration due to gravity is a vector, which means it has both a magnitude and a direction. The accele ...

                                               

Adhesion

Adhesion is the process in which dissimilar particles stick together. In the case of similar particles, this effect is called cohesion. Adhesion results from the physical properties of the interface between two phases. The forces that result in a ...

                                               

Air

Air refers to the Earths atmosphere. Air is a mixture of many gases and tiny dust particles. It is the clear gas in which living things live and breathe. It has an indefinite shape and volume. It has mass and weight, because it is matter. The wei ...

                                               

Boltzmann constant

For the constant pertaining to energy of black body radiation see Stefan–Boltzmann constant The Boltzmann constant is a physical constant. It is defined to be 1.380 649 × 10 −23 J/K. It relates the average kinetic energy of a particle in a gas wi ...

                                               

Bose-Einstein statistics

In statistical mechanics, Bose-Einstein statistics means the statistics of a system where you can not tell the difference between any of the particles, and the particles are bosons. Bosons are fundamental particles like the photon. The Bose-Einst ...

                                               

Capillary action

Capillary action means either of two things: When liquid moves through something that is full of little holes like a sponge. When liquid moves through thin tubes. Capillary action is a result of the surface tension of liquids. An example of capil ...

                                               

Casimir effect

The Casimir effect is the attraction of two metal plates in a vacuum. This effect occurs because of a side effect of the quantum uncertainty principle, where virtual particles cause the plates to be slightly pushed towards each other.

                                               

Cat righting reflex

The cat righting reflex is a cats natural ability to turn itself around as it falls so it will land on its feet. This righting reflex starts to happen at 3–4 weeks of age. The cat has entirely learned how to do this by 6–7 weeks. Cats are able to ...

                                               

Cauchy distribution

In mathematics, the Cauchy-Lorentz distribution is a continuous probability distribution with two parameters: a location parameter and a scale parameter. As a probability distribution, it is usually called a Cauchy distribution. Physicists know i ...

                                               

Center of mass

Center of mass or barycenter of a system is the average position of all the mass in a system. In a rigid body, the centre of mass is always in the same place. In a loose collection the center of mass may be in space, as it is in the Solar System. ...

                                               

Charged particle

A charged particle, also called an ion, is an atom with a positive or negative charge. This happens whenever something called an ionic bond forms. Two particles that have different numbers of electrons start reacting to each other. The particle t ...

                                               

Classical physics

Classical physics are the physics that were made before the 20th century. This part of physics studies things like movement, light, gravity, and electricity. Most of physics today uses ideas that are more complicated than the ideas of classical p ...

                                               

Coefficient of friction

A coefficient of friction is a value that shows the relationship between two objects and the normal reaction between the objects that are involved. It is a value that is sometimes used in physics to find an objects normal force or frictional forc ...

                                               

Colloid

A colloid is a mixture of one substance spread out evenly inside another substance. They can be in two different phases or states of matter. One substance is the dispersion medium, such as water or gas. The other is the dispersed medium, sometime ...

                                               

Conjugate variables

Conjugate variables are special pairs of variables that dont give the same result when you do a certain mathematical operation with them. This means that x*y is not equal to y*x. Here, the * does not mean multiplication. It could mean addition, s ...

                                               

Cooper pair

A Cooper pair is a pair of free electrons within a solid that act together as one quasiparticle and in large numbers give rise to superconductivity. Physicists explain superconductivity by describing what happens when temperatures get cold. The t ...

                                               

Diffraction

Diffraction is a physics concept which occurs when waves bend around small obstacles, or spread out after they pass through small openings. Diffraction occurs with all waves, including sound waves, water waves, and electromagnetic waves such as l ...

                                               

Dirac fermion

In particle physics, a Dirac fermion is a particle that is different from its antiparticle. This is true for most particles. In the standard model of physics, each particle has its antiparticle. They are named for Paul Dirac, and can be modeled w ...

                                               

Displacement vector

A displacement vector is a concept from mathematics. It is a vector. It shows the direction and distance traveled with a straight line. It is often used in physics to display the speed, acceleration and distance of an object traveled.

                                               

Dissipation

In physics, dissipation includes the concept of a dynamical system where important mechanical modes, such as waves or oscillations, lose energy over time, typically due to the action of friction or turbulence. The lost energy is converted into he ...

                                               

Doubochinskis pendulum

Doubochinskis pendulum is an experiment with an oscillator and a magnet. The most simple case is that of a pendulum that interacts with an oscillator. The pendulum will swing at a frequency of one swing per period of 1-2 seconds. A stationary ele ...

                                               

Elastic collision

An elastic collision is when two objects collide and bounce back with little or no deformation. For example, two rubber balls bouncing together would be elastic. Two cars hitting each other would be inelastic, as the cars crumple, and do not boun ...

                                               

Electronvolt

The electron-volt or electron volt, symbol eV, is used to measure energy. It is defined as the amount of energy an electron gains after being accelerated by 1 volt of electricity. Joules are used often for energy measurement, but it is sometimes ...

                                               

False vacuum

A false vacuum is an idea from theoretical physics: In quantum field theory, such a vacuum might exist for a very long time, before it changes its state. Much like with a true vacuum, a false vacuum exists where the energy is minimal. In the case ...

                                               

Field strength

In physics, the field strength of a field is the magnitude of its value. This means that the force exerted by the field on a given object is proportional to the field strength. In differential geometry, the field strength is another name for the ...

                                               

Flight

Best adapted for long controlled powered flight are flying birds and insects, bats Chiroptera, and the extinct pterosaurs. All of these animals use or used the aerodynamic principles of flight, using the load-bearing properties of the wing for ac ...

                                               

Free fall

Free fall is what happens when an object is let to fall on its own without propulsion or resistance. Someone who is standing is not in free fall, but someone jumping from an airplane is, until air resistance builds up, ending in terminal velocity ...

                                               

Fresnel lens

A Fresnel lens is an optical lens, which was originally developed for Lighthouses. It is named after its inventor, French physicist Augustin-Jean Fresnel. The name is pronounced /freɪˈnɛl, the is silent. Before Fresnel, Buffon and Condorcet propo ...

                                               

G-Force

The g-force of an object is its acceleration relative to free fall. On earth this is 1g, or 9.8 meters per second squared or equivalently 9.806 65 newtons of force per kilogram of mass. Astronauts experience unusually high and low g-forces. G-for ...

                                               

Glauber dynamics

In statistical physics, Glauber dynamics is a way to simulate the Ising model on a computer. It is a type of Markov Chain Monte Carlo algorithm.