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.
This was our understanding until a century ago, when in 1905, Albert Einstein came up with the theory of special relativity, which has been shown to be correct to a very high accuracy. In special relativity, time is treated almost like another dimension; one may perform a special type of rotation between space and time, which is called a boost. Nothing can be accelerated to move faster than light. Also, energy equals mass times the speed of light squared. In an elegant mathematical framework, time is treated as another dimension, so we may consider space-time to be 4 dimensional.
Einstein then went on to unify special relativity with gravity. Mathematical consistency led him to the theory of general relativity, where space-time is curved. Again this theory has passed many tests. In the past 100 years, it became very clear that we live in a quantum world, where atoms, molecules, and electronics obey quantum rules quite differently from our daily experience. It is natural for scientists to unify quantum mechanics and Einstein's gravity. This turns out to be a very challenging problem. Many great minds (including Einstein himself) had tried over the years. Twenty years ago, such a theory was finally discovered, namely, the superstring theory. The theory is very deep. After an intensive effort over 20 years by hundreds of physicists and mathematicians, we have some idea what the theory is telling us. To start out, the theory has 10 dimensions, 6 more spatial dimensions than our experience tells us. We believe these 6 extra dimensions are curled up into tiny sizes, much smaller than atoms, too small to be detected with the most powerful microscope.
Consider ants crawling on a tabletop. In their daily experience, they can explore only 2 dimensions, those of the table surface. They may see a bee up flying, or occasionally landing on the table top, but that 3rd dimension is something they can only see or imagine, not experience. Perhaps we are in an analogous situation. Instead of a tabletop, we live in a 3-dimensional space called 3-brane (a name generalizing 2-brane, i.e., membrane). For some reason, we (i.e., atoms, molecules, photons etc.) are stuck in this 3-brane, even though there are 6 additional dimensions out there. Gravity, like the bee, can go everywhere. We call this the brane world, a rather natural phenomenon in superstring theory. At the moment, physicists are working hard to understand this scenario better and to find ways to experimentally test this idea.
- How accurate is the VSEPR model of molecular geometry for predicting the shapes of large, complex molecules?
- Is jello an amorphous solid? If not, what is it?
- I have heard of ways to get energy through the braking of a car. How does this work?
- What exactly are isotopes? I know that an element with different proton and neutrons is an isotope. So would it mean that (for example) Barium is an isotope but Aluminum is not?
- Why is the sky blue?
- Why, when you breathe in helium, does your voice change?
- How do minerals and nutrients form? Why do some foods have metals in them?
- How come deserts have sand instead of dirt and soil?
- Is it possible to determine the resonance frequency of an object that has a diameter in nanometers in size (such as a cell)?
- Where does liquid nitrogen come from and how is it made?