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.

Previous Week's Question Published: 3 December, 1998 Next Week's Question
Light rays, refraction play tricks with mind
Question
When I place a straw in a glass of soda, the part of the straw in the water appears bigger and also seems bent as I look down into the cup. Why does it look bigger and why does it appear to bend upon entering the water?

Question
If you look at a distant tree from its top to bottom, your eye scans a small angle. If you are standing next to the same tree, you have to tilt your head back to cover the whole tree, so the sense of the size of an object depends on the angle you see between its outer points. When you look at something in water, the light from it that gets to your eye must pass through the water surface separating the air and water. The rays of light from the water bend towards the surface as they enter the air. (This is called refraction.) In fact, the more the rays are angled to the surface, the more they bend. Because of all this, the angle you have to move your eye to see the full object gets bigger and therefore the object in the water looks bigger. The refraction is directly responsible for the apparent bend in the straw.

When an eagle dives for a fish, and heads directly for the fish he sees, he misses because the fish is lower than it appears to him. Try this: put a nickel at the bottom of a mug. Look into the mug at a low angle, such that the coin is just out of view. Pour in water slowly and watch the coin appear to rise from the bottom and be not only visible but also bigger. When you look at a 3 inch long fish in an aquarium, it will appear to be about 4 inches long.

Try this question: From our story above, our eagle has learned that the fish is actually lower than it appears, so he aims low. Now, some fish catch insects by squirting a jet of water at a bug just above the surface. Should he aim high or low?

Related Questions