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Related Concept Videos

Atomic Structure01:33

Atomic Structure

All matter is composed of atoms, the smallest individual units of elements. Each atom is made up of three subatomic particles: protons, neutrons, and electrons. Together, these three particles account for the mass and the charge of an atom.The History of Atomic TheoryThe first person to propose that everything on Earth is made up of tiny particles was the Greek philosopher Democritus, around 450 B.C. He used the term atomos, Greek for “indivisible,” from which the modern term “atom” is derived.
Atomic Orbitals02:44

Atomic Orbitals

An atomic orbital represents the three-dimensional regions in an atom where an electron has the highest probability to reside. The radial distribution function indicates the total probability of finding an electron within the thin shell at a distance r from the nucleus. The atomic orbitals have distinct shapes which are determined by l, the angular momentum quantum number. The orbitals are often drawn with a boundary surface, enclosing densest regions of the cloud.
Nuclear Stability03:18

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together in the...
Nuclear Fission02:50

Nuclear Fission

Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger binding energies per nucleon—that is, mass numbers and binding energies per nucleon that are closer to the “peak” of the binding energy graph near 56. Sometimes neutrons are also produced. This decomposition of a large nucleus into smaller pieces is called fission. The breaking is rather random with the formation of a large number of different...
Nuclear Fusion02:45

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
Atomic Structure01:17

Atomic Structure

The Greek philosopher Democritus proposed that everything on Earth is made up of tiny particles called atomos, Greek for "indivisible," from which the modern term "atom" is derived. In the 19th century, John Dalton proposed the atomic theory that is still largely correct today. He put forth five postulates to explain how atoms made up the world around us. (1) All matter is composed of infinitely small particles or atoms. (2) All atoms of a given element are identical to one another and (3) are...

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Related Experiment Video

Updated: Jul 19, 2026

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
06:04

Simulation of the Planetary Interior Differentiation Processes in the Laboratory

Published on: November 15, 2013

Isolated star formation: from cloud formation to core collapse.

Derek Ward-Thompson1

  • 1Department of Physics and Astronomy, Cardiff University, Post Office Box 913, Cardiff, UK. D.Ward-Thompson@astro.cf.ac.uk

Science (New York, N.Y.)
|January 5, 2002
PubMed
Summary

Star formation is a fundamental astrophysics problem. Current models struggle to explain observations of turbulence and magnetic fields in star-forming regions, despite advanced technology and computing power.

Area of Science:

  • Astrophysics
  • Star Formation
  • Cosmic Physics

Background:

  • Star formation is a fundamental astrophysical problem, crucial for understanding galaxy and solar system evolution.
  • Key physical processes involve turbulent, partially ionized media with non-uniform magnetic fields.
  • Ongoing debate focuses on turbulence decay times and the interplay of magnetic fields and turbulence.

Purpose of the Study:

  • To investigate the complex physical processes governing star formation.
  • To reconcile theoretical models with observational data regarding turbulence and magnetic fields.
  • To advance our understanding of the timescales and mechanisms in stellar evolution.

Main Methods:

  • Utilizing advanced observational data from millimeter-wave cameras to analyze temperature and density profiles.

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Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

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Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks
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Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks

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Last Updated: Jul 19, 2026

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
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Simulation of the Planetary Interior Differentiation Processes in the Laboratory

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Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System
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Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

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Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks
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Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks

Published on: February 10, 2023

  • Performing statistical calculations on the lifetimes of collapsing and pre-collapse objects.
  • Developing complex computational models incorporating magnetic and turbulent effects.

    • Main Results:

    • Technological advancements enable detailed observation of star-forming regions.
    • Increased computing power facilitates more sophisticated modeling of physical processes.
    • No single current model accurately reproduces all observed phenomena.

    Conclusions:

    • Star formation remains a complex challenge in astrophysics.
    • Current models are insufficient to fully explain observed star formation processes.
    • Further research is needed to integrate magnetic fields, turbulence, and observational data effectively.