Dating the earth

1. Dating the earth William Mendez 7th ESS 10

2. Radiometric dating • The original radioactive element is called the parent. The radioactive atom parent enters a new stage coming into the daughter, a new period in its half life. (a half life is the time it takes for half of the starting parents to decay.). When observing a radioactive element you can notice its instability giving of particles transforms element a into element b. thus becoming more stable.

3. The shortcomings of Radiometric dating • The snag on this is that you have to assume 3 things about your sample. • You know the history of the rock your dating • Ratio of daughter/parent isotopes is known - (the parent isotope is its start of the decay, when it releases enough radiation over a period of time it mutates said element into another. The now changed element becomes the daughter, the next stage in its decay.) • A constant decay rate - knowing something had a consistent decay rate is fallacy. during certain sessions of our years such as winter and summer, the decay rate can either speed up or slow down, they know it involves the sun but there not exactly sure what really causes the effect.

4. Carbon dating • carbon 12 and carbon 14 are the important in discovering the age of a rock. after something organic dies carbon 14 starts to see a drop in atoms. After lets say after 5,730 years the amount of carbon 14 would be cut in half, then comparing to another carbon. Like carbon 12 you can find the age of the material. • the problem with the comparing of carbon atoms is that the really old fossils/rocks have an extremely low or no carbon 14 so it is impossible to accurately measure

5. Relative dating techniques • Imagine cutting the earth in half, when looking closely you would be able to tell that there are many layers. Common since tells us that the older layers are on the bottom, while the younger sits on top. The only time that isn't true is when there's an earthquake causes and uplift or something to raise or lower a section of layers. • an animal that died throughout the ages are left as place markers throughout time. by looking at a fossil and knowing what time period it is from it helps you to more accurately see what the age of the rocks/earth are around it.

6. Video http://www.youtube.com/watch?v=Dwza37LRCOE

7. Sources • http://www.seekingtruth.co.uk/age_of_earth.htm • http://www.forbes.com/sites/alexknapp/2011/05/03/radioactive-decay-rates-may-not-be-constant-after-all/ • http://www.nhm.ac.uk/nature-online/science-of-natural-history/the-scientific-process/dating-methods/index.html • http://en.wikipedia.org/wiki/Radiometric_dating • http://science.howstuffworks.com/environmental/earth/geology/radiocarbon-dating-change-archaeology.htm