Susan Kay Garrison, age 9, of Newport News, Virginia, for her question:

Where is the deepest spot in the Atlantic Ocean?

The ocean floor is a mile or two below the surface waves. You might have to strain your brain to figure how to measure down through all this deep., dark water. Ocean experts use several tricky gadgets to do the job, but the work is never easy. It takes time to measure the depth of each underwater spot and the ocean is immense. The North and South Atlantic Oceans cover about one fifth of the entire world. Our ocean experts have not had time to measure every spot of the floor beneath all this watery ocean, but they have taken thousands of sample measurements. They can place the important undersea mountain ranges on charts of the ocean floor. They can add many of the deep troughs and ditches in the bed of the sea.

The deep ocean is dark and some of its ditches were found by accident. No one can say whether all of them have been discovered. The South Atlantic has a pit almost 27,000 feet deep. But the deepest ditch found so far is in the North Atlantic. It is off the northern shores of Puerto Rico andUt dips down 27,948 feet into the sea. The bottom of Milwaukee Deep is more than five miles below the waves. But we have found even deeper pits in the floor of the Pacific Ocean.