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Various examples of physical phenomena

Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.

Physics is one of the oldest academic disciplines and, through its inclusion of astronomy, perhaps the oldest. Over much of the past two millennia, physics, chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the Scientific Revolution in the 17th century these natural sciences emerged as unique research endeavors in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in academic disciplines such as mathematics and philosophy.

Advances in physics often enable advances in new technologies. For example, advances in the understanding of electromagnetism, solid-state physics, and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus. (Full article...)

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Figure 1. A mechanical filter made by the Kokusai Electric Company intended for selecting the narrow 2 kHz bandwidth signals in SSB radio receivers. It operates at 455 kHz, a common IF for these receivers, and is dimensioned 45×15×15 mm (1+34×712×712 in).

A mechanical filter is a signal processing filter usually used in place of an electronic filter at radio frequencies. Its purpose is the same as that of a normal electronic filter: to pass a range of signal frequencies, but to block others. The filter acts on mechanical vibrations which are the analogue of the electrical signal. At the input and output of the filter, transducers convert the electrical signal into, and then back from, these mechanical vibrations.

The components of a mechanical filter are all directly analogous to the various elements found in electrical circuits. The mechanical elements obey mathematical functions which are identical to their corresponding electrical elements. This makes it possible to apply electrical network analysis and filter design methods to mechanical filters. Electrical theory has developed a large library of mathematical forms that produce useful filter frequency responses and the mechanical filter designer is able to make direct use of these. It is only necessary to set the mechanical components to appropriate values to produce a filter with an identical response to the electrical counterpart. (Full article...)
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The Feynman Lectures on Physics including Feynman's Tips on Physics: The Definitive and Extended Edition (2nd edition, 2005)

The Feynman Lectures on Physics is a 1964 physics textbook by Richard P. Feynman, Robert B. Leighton and Matthew Sands, based upon the lectures given by Feynman to undergraduate students at the California Institute of Technology (Caltech) in 1961–63.

It includes lectures on mathematics, electromagnetism, Newtonian physics, quantum physics, and the relation of physics to other sciences. Six readily accessible chapters were later compiled into a book entitled Six Easy Pieces: Essentials of Physics Explained by Its Most Brilliant Teacher, and six more in Six Not So Easy Pieces: Einstein's Relativity, Symmetry and Space-Time.

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A diagram showing the measured and predicted half-lives of heavy and superheavy nuclides, as well as the beta stability line and predicted location of the island of stability.
A diagram by the Joint Institute for Nuclear Research showing the measured (boxed) and predicted half-lives of superheavy nuclides, ordered by number of protons and neutrons. The expected location of the island of stability around Z = 112 is circled.

In nuclear physics, the island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes of these elements. It is predicted to appear as an "island" in the chart of nuclides, separated from known stable and long-lived primordial radionuclides. Its theoretical existence is attributed to stabilizing effects of predicted "magic numbers" of protons and neutrons in the superheavy mass region.

Several predictions have been made regarding the exact location of the island of stability, though it is generally thought to center near copernicium and flerovium isotopes in the vicinity of the predicted closed neutron shell at N = 184. These models strongly suggest that the closed shell will confer further stability towards fission and alpha decay. While these effects are expected to be greatest near atomic number Z = 114 and N = 184, the region of increased stability is expected to encompass several neighboring elements, and there may also be additional islands of stability around heavier nuclei that are doubly magic (having magic numbers of both protons and neutrons). Estimates of the stability of the elements on the island are usually around a half-life of minutes or days; some estimates predict half-lives of millions of years. (Full article...)

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Fundamentals: Concepts in physics | Constants | Physical quantities | Units of measure | Mass | Length | Time | Space | Energy | Matter | Force | Gravity | Electricity | Magnetism | Waves

Basic physics: Mechanics | Electromagnetism | Statistical mechanics | Thermodynamics | Quantum mechanics | Theory of relativity | Optics | Acoustics

Specific fields: Acoustics | Astrophysics | Atomic physics | Molecular physics | Optical physics | Computational physics | Condensed matter physics | Nuclear physics | Particle physics | Plasma physics

Tools: Detectors | Interferometry | Measurement | Radiometry | Spectroscopy | Transducers

Background: Physicists | History of physics | Philosophy of physics | Physics education | Physics journals | Physics organizations

Other: Physics in fiction | Pseudophysics | Physics lists | Physics software | Physics stubs

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Physics topics

Classical physics traditionally includes the fields of mechanics, optics, electricity, magnetism, acoustics and thermodynamics. The term Modern physics is normally used for fields which rely heavily on quantum theory, including quantum mechanics, atomic physics, nuclear physics, particle physics and condensed matter physics. General and special relativity are usually considered to be part of modern physics as well.

Fundamental Concepts Classical Physics Modern Physics Cross Discipline Topics
Continuum Solid Mechanics Fluid Mechanics Geophysics
Motion Classical Mechanics Analytical mechanics Mathematical Physics
Kinetics Kinematics Kinematic chain Robotics
Matter Classical states Modern states Nanotechnology
Energy Chemical Physics Plasma Physics Materials Science
Cold Cryophysics Cryogenics Superconductivity
Heat Heat transfer Transport Phenomena Combustion
Entropy Thermodynamics Statistical mechanics Phase transitions
Particle Particulates Particle physics Particle accelerator
Antiparticle Antimatter Annihilation physics Gamma ray
Waves Oscillation Quantum oscillation Vibration
Gravity Gravitation Gravitational wave Celestial mechanics
Vacuum Pressure physics Vacuum state physics Quantum fluctuation
Random Statistics Stochastic process Brownian motion
Spacetime Special Relativity General Relativity Black holes
Quanta Quantum mechanics Quantum field theory Quantum computing
Radiation Radioactivity Radioactive decay Cosmic ray
Light Optics Quantum optics Photonics
Electrons Solid State Condensed Matter Symmetry breaking
Electricity Electrical circuit Electronics Integrated circuit
Electromagnetism Electrodynamics Quantum Electrodynamics Chemical Bonds
Strong interaction Nuclear Physics Quantum Chromodynamics Quark model
Weak interaction Atomic Physics Electroweak theory Radioactivity
Standard Model Fundamental interaction Grand Unified Theory Higgs boson
Information Information science Quantum information Holographic principle
Life Biophysics Quantum Biology Astrobiology
Conscience Neurophysics Quantum mind Quantum brain dynamics
Cosmos Astrophysics Cosmology Observable universe
Cosmogony Big Bang Mathematical universe Multiverse
Chaos Chaos theory Quantum chaos Perturbation theory
Complexity Dynamical system Complex system Emergence
Quantization Canonical quantization Loop quantum gravity Spin foam
Unification Quantum gravity String theory Theory of Everything

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