Absolute dating is a method of determining the specific date of a paleontological or archaeological artifact or location based on a specific time scale or calendar. Scientists base absolute dating on measurable physical ... More »

Women who wish to conceive boys can follow the Shettles method or the Whelan method, using an ovulation calendar to time intercourse in relation to the date of ovulation. Both report varying levels of success but neither... More »

Carbon-14 dating uses the ratio of radioactive carbon-14 to non-radioactive carbon-12 to determine if the ratio is the same as in living organisms, or if it is lower, indicating that the carbon-14 has decayed during a pe... More »

According to the Smithsonian Institute, using radiodating of sedimentary rock tells the date of formation of the original igneous rock, which, through the processes of weathering and erosion, formed the layers of the sed... More »

Tin was discovered prior to the beginning of recorded history, so its exact date of discovery is unknown. Its first known use was at the start of the Bronze Age in approximately 3000 B.C. During this time period, it was ... More »

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Rocks are formed in three primary ways, and each method produces rocks with different characteristics. Rocks are either classified as sedimentary, igneous or metamorphic, depending on the manner in which they were formed... More »

The method of reading a grade rod varies by type. Engineer's and builder's rods are read from the bottom to the top, while direct elevation rods are read from top to bottom. More »

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