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.
For example, 1 liter of water contains roughly one million, billion, billion molecules, each composed of one oxygen and two hydrogen atoms.
In solids, the molecules composing the material stick strongly to each other and cannot move. In liquids (such as water), on the other hand, the molecules are less strongly attracted to each other and can rearrange. At room temperature, the relatively small water molecules flow past one another to form a liquid.
The molecules that make up cornstarch are very different from the small water molecules. They consist of long chains of repeating units called sugars. Sucrose or table sugar has two such repeating units per molecule, whereas starch has many, many, more. In pure cornstarch, the sugar chains stick strongly and cannot move past one another, thus starch is a solid.
However, if we add water to starch, the water gets between the starch chains, separates them and allows the chains to slide past one another; the mixture behaves as a liquid.
If we apply pressure to the starch mixture, the water is squeezed out from between the chains and they are able to grab one another. Sliding is prevented and the material behaves as a solid. If we release the pressure, the water can enter between the chains to allow sliding once more.
This behavior is not limited to the molecular scale. A similar phenomena occurs when you run on wet sand at the beach. If you run fast and generate pressure quickly the sand feels hard as water is squeezed out and the sand particles cling to each other. If you step slowly to apply the pressure gradually, the sand particles have time to move past one another -- your foot sinks!
- How do CDs Work?
- If the electrons are attracted to the protons, why don't they come crashing into the nucleus?
- Is jello an amorphous solid? If not, what is it?
- Why does wood turn to ashes in my fireplace?
- If radioactive elements are getting converted into half in each of their successive half lives, then are radioactive elements going to disappear from universe after certain amount of time?
- From what metals are electromagnets made?
- How is calcium measured in bone? (without using blood, as this applies to a forensic anthropological question). And, what is the procedure or method of doing so? Is there any special tools, or devices needed?
- How is rubber made?
- Why do the electrons of an atom orbit around the nucleus?
- Why is the center of the earth hot?