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.
Human beings require over a dozen different minerals in their diets. These include calcium and phosphorous that we need to make bones and teeth, iodine that we need to make thyroid hormone, and iron that we need as part of certain proteins including the hemoglobin in red blood cells. Much of our mineral intake comes from the foods we eat, but we also obtain minerals from water sources, salts, and food additives.
The second group is the carbon-containing or organic nutrients that make up the bulk of our diets and provide us with energy. Organic nutrients include proteins, carbohydrates (sugars and starches), fats, and vitamins and are synthesized by living cells from simpler compounds. Green plants on land and photoplankton that live in water (like algae and a special group of photosynthetic bacteria) form the base of the organic nutrient chain. These chlorophyll-containing forms of life use energy from sunlight to combine carbon dioxide (CO2) from the atmosphere and water (H2O) to make carbohydrates (CnH2nOn) by a process we call photosynthesis. Biologists call plants and photoplankton "producers" because of this ability to make organic compounds (like sugars and starches) from inorganic compounds (CO2 and H2O) in the environment.
Animals and most microorganisms cannot carry out photosynthesis and must have pre-formed organic material in their diets. Biologists call bacteria and animals "consumers" because they obtain food by eating other organisms. Bacteria generally have simple nutrient needs. Most bacteria need a simple organic carbon source, usually from decaying plant or animal life. Animals and humans, on the other hand, have complex nutritional needs and require a number of different organic compounds in their diets. We obtain organic nutrients - proteins, carbohydrates, fats including some essential fatty acids, and 13 essential vitamins - by consuming a variety of plant and animal foods.
Why do some foods have metals in them? Many chemical elements or minerals are also called metals because of their properties. Some of the minerals (like sodium and potassium) required in our diets are metals. Although we need a certain amount of each of the essential minerals in our diets, too much can be harmful or toxic. There is also concern about the pollution of our food supply with toxic compounds formed from some minerals that we do not need. The best-known example is the industrial pollution of some rivers and lakes with waste mercury. Bacteria convert the mercury to organic forms, and the mercury makes its way into marine organisms and fish, resulting in the need to limit our consumption of fish from these bodies of water.
How do minerals form? We know elements are formed by a complex process called atomic fusion that occurs inside the centers of stars, but this nutritional biochemist will leave the question of solar system formation for the astrophysicists and theologians!
- What kinds of plants live on the bottom of the ocean?
- How do you grow seedless watermelons?
- What is the most common type of blood?
- Why does popcorn stick to your tongue or anything else that is damp?
- When was the very first dinosaur on Earth?
- I would like to know why is it that most people like to finish off a meal with something sweet? Or is it just natural to balance savory and sweet? If so, why not the other way around? Is it purely from the gastronomic angle or that's the way our senses and palate are built?
- How exactly are nocturnal animals able to see in the dark?
- Will your skin change color if you eat enough of a colorful food? (For example, if you eat a lot of carrots, will your skin turn orange?)
- Why does fruit ripen?
- Why can birds fly but penguins can't?