Archives of Ask A Scientist!
About "Ask A Scientist!"
On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.
Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.
An element not found in nature (i.e., synthetic) is synthesized by bombarding the nucleus of a target element with smaller particles such as protons, a-particles (He nuclei) or neutrons. Because of their positive charges, protons and a-particles need to be accelerated to enormous velocities to get them to collide and "react" with the positively charged nucleus of a target atom; the repulsion of like charges must be overcome! Since neutrons are not charged, the "repulsion problem" is circumvented, and they are very important reagents for synthesizing radioisotopes. All synthetic elements are radioisotopes, which are isotopes that undergo measurable nuclear decay. A target element is placed in a chamber in a nuclear reactor that is subject to a neutron flux in order to transmute it into another isotope or different element. There are fancier neutron sources, such a spallation sources where neutrons are themselves a product of a bombardment, but nuclear reactors are the only practical means of synthesizing useful quantities of radioisotopes. For example, 43Tc99m is produced from 42Mo98 in this manner. Tc turns out to be rather benign, and is injected in the body in various chemical forms to image the heart and detect certain cancers; it is "observed" by loss of gamma rays, and its use in medicine has saved thousands of lives.
Radioisotopes (some occur naturally!) are also produced as a byproduct of fission in nuclear reactors, and some can be harvested by separating them from others in a nuclear fuel rod. In a fission reaction, a fuel, typically 92U235, 92U238 or 94Pu239 depending on the type of reactor, absorbs a neutron, becomes unstable, and splits into two products, releasing more neutrons and a tremendous amount of energy in the process. Because of separation difficulties and the danger of working with spent fuel rods, the synthesis of elements from fission is mostly limited to research purposes. However, neutrons generated through fission can be captured by 92U238 to ultimately produce 94Pu239, which is a fuel itself. This is essentially the way a breeder reactor -- a reactor that produces more fuel than it consumes -- operates.
- How do scientists know there are such things as atoms?
- What is a mole?
- From what metals are electromagnets made?
- What shape can a volcano be?
- How do airplanes fly?
- How many rocks are there on Earth?
- I understand lead was replaced by graphite in pencils. Was this because of lead's harmful effects or because of economic reasons that the lead was replaced?
- How do you make a man made element?
- Why do coals appear 'red hot' in a fire and is this the hottest spot in a fire?
- Is it possible to use electrolysis or another method to separate NaCl into sodium and free floating chlorine gas?