NASA site explores what a comet's nucleus is composed of. Animation and photographs are provided as well.

The characteristics, structure, and functions of the nucleolus are described.

The number of protons in the atom of an element determines its place in the Periodic Table. The number of electrons in an atom is the same as the number of protons. These electrons are arranged in shells or 'energy levels' around the...

Acting as part of an overview on quantum theory, this section of the site deals with electrons and orbitals. In addition to explain what an orbital is, the site explains the movement of the electron in relation to the nucleus.

Site provides extensive information in the study of comets. Includes excellent graphics that depict what comets look like as they travel through the solar system. Also includes information on how comets may have effected the Earth's...

This site provides an illustrated and animated story that seeks to answer several questions. What are atoms made of? What is keeping a nucleus intact? What happens if you try to separate two quarks? Are quarks fundamental?

This site provides a great series on the neutron discovered by James Chadwick. Includes a seven-page series that covers what is inside the nucleus, the elusive neutron, beryllium radiation, Chadwick's discovery, neutrons from beryllium,...

From the Mad Scientist Network web site. Using a question and answer format, this page provides a thorough discussion of fusion reactions. Fusion and fission are compared and contrasted and the mechanisms which must occur to initiate and...

[Free Registration/Login may be required to access all resource tools.] The nucleus is only found in eukaryotic cells. It contains most of the genetic material of the cell. It is surrounded by a double membrane, or nuclear envelope, that...

What is the cell structure of a prokaryote? Check out these cells with unorganized nuclei featured.

From The Mad Scientist Network web site. Using a question and answer format, this page discusses three types of nuclear reactions - spontaneous decay reactions, nuclear fision reactions, and nuclear fusion reactions. Each reaction type...

Activity 3 of this module investigates: How do we know what's inside an atom? From Ernest Rutherford's Gold Foil Experiment to his investigation of the Plum Pudding model, students become aware of the Nuclear Model of an Atom. Also in...

[Free Registration/Login may be required to access all resource tools.] Humans are in the same domain as trees and algae. What could they possibly have in common? It is the location of their DNA inside their cells. Their cells all have a...

[Free Registration/Login may be required to access all resource tools.] What a radioisotope is and why they have unstable nuclei. Elements in which all of the isotopes are radioactive.

This site from the encyclopedia Wikipedia provides a basic definition for what the atomic radius is, and an explanation of what covalent and metallic radii are.

Explains what the effective nuclear charge is and how electrons can create a shield between a nucleus and an outer electron. Presents exercises for comparing orbital sizes with effective nuclear charges. Requires Java.