Experts and nuclear neophytes alike can sharpen their knowledge of radioactivity and the radioactive elements with this pair of sites. A good starting point is The Living Textbook of Nuclear Chemistry, a collection of tutorials, papers, and other material hosted by Oregon State University, Corvallis. Visitors can study two texts on nuclear chemistry or download more than a dozen lab protocols, from dating uranium-containing minerals to using germanium radiation detectors. If you want to dig deeper, audio lectures explore advanced topics such as the synthesis of superheavy elements—the behemoths at the end of the periodic table, which scientists make by crashing smaller atoms into bulky elements like plutonium. For history buffs, 13 video clips look at developments in the field. For instance, Nobel laureate Glenn Seaborg recalls his group's discovery of plutonium in 1941 at the University of California, Berkeley, and the difficulties in isolating heavier elements.
If you can't remember the difference between parity and pair production, consult this glossary of more than 50 nuclear science terms from Lawrence Berkeley National Laboratory in California. Animations depicting processes such as alpha decay and hydrogen burning help etch the definitions in your mind.