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Kelvin knew that the Earth gets hotter with increasing depth (the geothermal gradient), and took this observation as evidence that the Earth is cooling off. Chamberlain challenged Kelvins assumption that the earth started as a molten body.
He believed the Earth started off as a molten mass and subsequently transformed to a hot solid mass during cooling. Instead, Chamberlain proposed a model of cold accretion for the Earth.
THE ORIGINAL RADIOACTIVE ISOTOPE IS CALLED THE PARENT ELEMENT.
THE MORE STABLE FORM IT TURNS INTO IS CALLED THE DAUGHTER ELEMENT.
Teach your students about absolute dating: Determining age of rocks and fossils, a classroom activity for grades 9-12.
So in order to date most older fossils, scientists look for layers of igneous rock or volcanic ash above and below the fossil.
Scientists date igneous rock using elements that are slow to decay, such as uranium and potassium.
He calculated the modern rate of salt delivery to the oceans, and suggested that the present salinity of ocean water would take at least 100 million years to develop.
In the 1860's, English physicist Lord Kelvin disagreed with Charles Lyells proposition that the earth behaves in a uniform, unchanging manner.
If we looked at a cross-section ofa tree or log we would notice that all through it are concentric circles radiating out from the center to the bark. Each ring is also different, and the thickness of each ring is representative of the length of the growing season.