 Given the information in the article, what is the purpose of a Geiger counter?
Then, remembering the dream, he added, “Oh, Dad, is it all right if I use the Geiger counter today?” “You may use the Geiger counter any time you want, Eddie,” Mr. Taylor said, “as long as you take good care of it. Suddenly the Geiger counter began clicking like everything.” But, from what I hear, there are plenty of rock formations. Still, one clue is as good as another when it comes to hunting uranium ore, I guess. It could start cavities. Get at it right away, and you’ll still have time to hunt your uranium. In fact, anything having to do with atomic science excited him. You couldn’t have a father who was head of the atomic-science department at Oceanview College without picking up a little knowledge along the way. Eddie knew that a radioisotope was a material which had been “cooked” in an atomic reactor until it was “hot” with radioactivity. When carefully controlled, the radiation stored up in such isotopes was used in many beneficial ways. One reason for asking that particular question was to keep from prying deeper into the subject of the radioisotope. At the speed atomic science is moving today, we simply can’t afford to waste time. “Anything else, Mom?” he asked, returning to the house and getting the Geiger counter out of the closet. Besides, there were plenty of other places around the outskirts of Oceanview where likely looking rock formations invited search with a Geiger counter. They had been ever since Eddie’s family had moved to Oceanview and his father had become head of the college’s atomic-science department. Teena’s father was chief engineer for the Acme Aviation Company, one of the coast town’s largest manufacturing concerns. “Don’t go too far out from town,” Mrs. Ross cautioned, as Eddie picked up the Geiger counter. At various rock mounds and outcroppings, Eddie switched on the Geiger counter. A slow clicking came through the earphones, but Eddie knew these indicated no more than a normal background count. There were slight traces of radioactivity in almost all earth or rocks. It was in the air itself, caused by mysterious and ever-present cosmic rays, so there was always a mild background count when the Geiger counter was turned on; but to mean anything, the needle had to jump far ahead on the gauge, and the clicking through the earphones had to speed up until it sounded almost like bacon frying in a hot skillet.
 To measure for radiation.
 To measure rock formation patterns.  To measure for radiation.  To find hidden rocks.  To measure gravity.