Nuclear weapons are one of the most powerful weapons available to humans in terms of energy released. So far, only two nuclear weapons have been used for war purposes in human history; launched by the United States on Hiroshima and Nagasaki. The Manhattan Project was started during World War II with the goal of producing an atomic weapon for the United States. Current nuclear weapons are more than 200 times more powerful. Nuclear weapons are the only weapons of mass destruction that are not blocked by international treaties. However, it is still considered a weapon of mass destruction due to its massive blast effect, radiation, and destructive potential. A single 1-megaton detonation would cause a 5,700-foot fireball with a blast wave traveling at about 784 mph. Heavily reinforced concrete buildings are reduced to shreds; firestorms rage for hours after the detonation. For those who survive nearby, radiation poisoning sets in. For decades, cancer, birth defects and other diseases plagued the towns near the detonation. However, this is not the worst that can happen. Most active nuclear weapons weigh more than 1 megaton; the largest ever reached being 50 megatons. Additionally, more than one bomb would likely be dropped. Nuclear weapons use radioactive substances for their warheads. Radioactive substances are made up of unstable radioactive atoms. Radioactivity occurs because all atoms are trying to become stable. Unstable atoms will “decay” until they are stable. If an unstable atom decays, it is said to be radioactive. The time it takes for half of an atom's nuclei to become stable is called the half-life of that element. Uranium 238 (the element most often used in nuclear weapons) has a half-life of 4.5 billion years. There are three types of...... middle of paper ......f the longest wars that almost brought the whole world to destruction. Today we recognize the horrific effects that nuclear war would cause and we are trying to have it banned internationally; in the same way that biological and chemical weapons (other types of weapons of mass destruction) have been banned. However, there is light at the end of the tunnel, as the study of nuclear weapons can be directed toward peaceful efforts (like clean energy). Thus allowing us to benefit from all the advantages of the study of nuclear physics without the disadvantages of nuclear proliferation. Works Cited Rossenfeld, Carrie. "Science." Atomic Archives. Ed. Chris Griffith. AJ Software & Multimedia, 2008. Web. May 20, 2010. Freudenrich PhD, Craig and John Fuller. “How Nuclear Bombs Work.” How it works. October 5, 2000. The web. May 20 2010. .