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24 week assessment

24 week assessment Science-Gwen Gould

QuestionAnswer
what is the scentifically accepted age of the earth 4.6 billion years
What is uniformitarism? Who identified the principle? Uniformitarianism is the principle that geologic processes that occurred in the past can be explained by current geologic processes. It was identified by James Hutton.
* What does the Law of Superposition state? A sedimentary rock layer is older than the layers above it and younger than the layers below.
* What does the Law of Cross-cutting Relationships state? A fault or igneous intrusion is always younger than the rock layers it cuts through.
* Radiometric Dating—what is a half-life? What do the terms “parent and daughter isotopes” mean? The half-life is the time it takes for half of the radioactive parent isotope to decay into the stable daughter isotope.
* What is Carbon-14 dating used for? A method of dating fossils (wood, shells, bones, etc.) that are less than 70,000 years old.
* What is an index fossil? A fossil that occurs in a rock layer of a particular geologic age—lived for a short time, was very common and world-wide.
* Why are there few fossils found in Precambrian rocks? There were not a lot of life forms (mostly bacteria), no hard parts to fossilize, and many of the rocks from that time period have been deformed (melted, eroded, faulted).
* What was the major cause of the Permian extinction? Many of the inland seas dried up. Many marine invertebrates went extinct.
* What is the major cause of the Cretaceous extinction? Asteroid strike
* What marks the boundary between the Pleistocene and the Holocene epochs? End of the last ice age
* Identify and define the layers of the Sun’s atmosphere: The photosphere. The chromosphere . The corona
* What causes them? Where are they usually seen? Caused by the interaction of the solar wind and Earth’s magnetosphere. Bright bands of light in the sky mostly seen at higher latitudes.
* What is the difference between a solar flare and a coronal mass ejection? A solar flare is an explosive release of energy that comes from the Sun and that is associated with magnetic disturbances on the Sun’s surface. A CME is made up of coronal gas that is thrown into space from the Sun.
* How does nuclear fusion create energy in the Sun’s core? On the Sun hydrogen is fused into helium.
* What is a sunspot? What is the average length of the sunspot cycle? A sunspot is a dark area of the photosphere of the Sun that is cooler than the surrounding areas, and that has a strong magnetic field. The average sunspot cycle is 11 years.
* What is cosmology? The scientific study of the Universe
* What is the scientifically accepted age of the universe? 14 billion years old
* Explain the Big Bang Theory The theory that the universe began as a small point of matter that suddenly and rapidly began expanding outward.
* What is the cosmic background radiation? Low levels of energy that are distributed evenly throughout the universe. This is evidence that supports the Big Bang Theory.
* What galaxy do we live in? Milky Way galaxy
Created by: gwen.gould