SECTION 17.2 Seafloor Spreading, continued In your textbook, read about magnetism. Use each of the terms helow just once to complete the passage. isochron magnetic field normal polarity older reversed polarity younger Earth's (17) __ has changed over time A field with the same orientation as today's ficld is said to have (18) __ A ficld that is oppositc the present field has (19) __ Magnetometers have been used to measure the occan floor's magnetic ficld. Magnetic data of the occan floor has bccn uscd to generate (20) __ maps, which have shown that the ocean floor is (21) __ near ocean ridges and (22) __ near deep-sca trenches In your textbook, read about ocean rocks and sediments, magnetism, and sealloor spreading. For each item in Column A. write the letter of the matching item in Column B. Column A __ 23. Device that can detect small changes in magnetic ficlds __ 24. Minerals containing this act like small compass needles and record the orientation of Earth's magnetic field at the time of their formation __ 25. Was constructed from data gathered from continental basalt flows __ 26. This type of line connects points on a map that have the same age __ 27. Each cycle of spreading and magma intrusion along an ocean ridge results in the formation of this Column B a. isochron b. iron C. geomagnetic time scale d. new occan crust e. magnetometer

This question is about seafloor spreading, magnetism, and ocean rocks and sediments. The first part of the question requires filling in the blanks with the appropriate terms. The second part of the question is a matching exercise where items in Column A need to be matched with the corresponding items in Column B. <br /><br />1. For the fill-in-the-blank section:<br /> - (17) The term that fits here is "magnetic field". Earth's magnetic field has changed over time.<br /> - (18) A field with the same orientation as today's field is said to have "normal polarity".<br /> - (19) A field that is opposite to the present field has "reversed polarity".<br /> - (20) Magnetometers have been used to measure the ocean floor's magnetic field. Magnetic data of the ocean floor has been used to generate "magnetic" maps.<br /> - (21) The ocean floor is "younger" near ocean ridges.<br /> - (22) The ocean floor is "older" near deep-sea trenches.<br /><br />2. For the matching section:<br /> - (23) The device that can detect small changes in magnetic fields is a "magnetometer" (e).<br /> - (24) Minerals containing iron act like small compass needles and record the orientation of Earth's magnetic field at the time of their formation (b).<br /> - (25) The "geomagnetic time scale" was constructed from data gathered from continental basalt flows (c).<br /> - (26) An "isochron" line connects points on a map that have the same age (a).<br /> - (27) Each cycle of spreading and magma intrusion along an ocean ridge results in the formation of "new ocean crust" (d).<br /><br />This explanation covers the reasoning behind each answer, providing a clear understanding of how the terms and concepts relate to the questions asked.