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.
As long as you are alive, you will have the same proportion of carbon 14 to other carbon as exists in other living organisms, but when you die, the radioactive carbon in your body begins to decay at a known rate. After about 5730 years, only half of the original radioactive carbon is left. Practically no carbon 14 remains after 50,000 years have gone by.
This means that carbon dating can only be used to date things that existed 50,000 years ago or less. It wouldn't be of any help in dating a dinosaur, for instance, because the last dinosaurs went extinct about 65 million years ago. Carbon dating was useful, though, to Cornell researchers and students who excavated some extinct woolly mammoths near Watkins Glen in central New York State; they determined that the mammoths lived at the end of the last Ice Age, some 12,000 years ago.
Although carbon dating can be done on a variety of materials, including bones of ancient people and other animals, it often works best on items that are essentially pure carbon, such as charcoal from wood fires. Radiocarbon dating of burnt plants has helped archaeologists trace the origins and spread of agriculture in many parts of the world.
In the past, scientists used equipment, such as Geiger counters, to detect and count the decay of individual atoms of carbon 14. Now they can also use atomic accelerators to find the amount of carbon 14 in a sample without having to wait for decay events. This allows the scientists to quickly date very small amounts of material, such as individual seeds.
More information on the history, uses, methods and problems of carbon dating can be found on the web at: www.c14dating.com
- How do minerals and nutrients form? Why do some foods have metals in them?
- How can you tell if a diamond is real or fake?
- How does a Van De Graaf generator work and what is it made from?
- How many types of rocks are there throughout the world?
- If plastic is made to be biodegradable, then won't the plastic forks and spoons we use dissolve in our mouth?
- How do scientists determine the viscosity of lava?
- I am currently studying electronics and how they work together to perform work. But I seem to get confused when the term "ground" is used. I understand that it is a "zero" reference point, and that it is a common return path for electrons to earth ground. I get stumped though when I see a schematic that has a ground attached to the negative end of a battery terminal in a dc circuit. Why don't the electrons just flow straight to ground? Then in an AC circuit schematic, I see a ground connection again connected to the negative side of a circuit. Can I assume that the ground is positively polarized which attracts the electrons?
- What exactly is radiation and why is it harmful? What can it do to you? How is it made?
- Specifically, we have paperwork that gives different names for several of the new elements: Db for number 105 instead of Ha and Bh for number 107 instead of Ns. Do we have names for 110, 111, or beyond? What is the last one that was made?
- Why are some lights called Halogen Lights? Do they contain elements from the Halogen group?