Strata Sample. 1. Make a drawing of the strata sample (beaker) in your fold. Be sure to add color :)

Transcription

1 strata: layer of sedimentary rock/soil Strata Sample 1. Make a drawing of the strata sample (beaker) in your fold. Be sure to add color :) 2. Identify which layer is the OLDEST and which layer is the YOUNGEST Below your drawing, write the relationship between the depth of the layer and the amount of time that has passed

2 Fossils 3. Create a scale with the terms OLDEST to YOUNGEST oldest youngest 4. After examining the fossils, identify which fossil is the oldest through to the youngest 5. Next to your scale, glue the fossils in the correct order, along the scale. Be sure to include fossil names.

3 Hyracotherium

4 Merychippus

5 Equus

6 How Are Fossils Formed? 5. Read the little paragraph of fossil formation 6. Then watch a short video on fossil formation 7. In your fold, create a flow chart explaining how fossils are formed

7 Fossil Formation In order for fossils to form, there must be a way to preserve the dead remains of animals and plants for a time so that they do not decay completely. The most common way that this occurs is on the bottom of bodies of water. When an animal of plant dies and falls into the water, the remains are sometimes covered up quickly by sediments. The layers of sediment form a protective covering to slow the process of decay. Over thousands of years, the sediments around the remains harden into rock. The dead animal or plant remains eventually decay leaving an empty space inside the sedimentary rock. Minerals filter down into this space and harden into rock forming a shape just like the animal or plant. This process is called fossilization. The mineral remains are called fossils.

8 Fossil Formation (continued) Sometimes there are no minerals that filter down into the empty space in the rock. The space that is left is called an imprint. Some common fossil imprints are dinosaur tracks which are formed when the large animals left their tracks on the bottom of shallow seas or rivers. There are other ways that fossils can be preserved. Many animals have been found preserved in ice in Siberia. Other fossils, especially Insects, are found imbedded in amber (a sticky sap from trees that covers the insects and then hardens).

9 How Are Fossils Dated? 8. Read the paragraph on how fossils are dated 9. In your fold, identify the 2 methods of fossil dating. Be sure to include a brief description of each method.

10 How To Date A Fossil (without spending a fortune on dinner & flowers) Have you wondered how the age of fossils are determined? There are several different methods scientists use to determine age of fossils. Sometimes, it is possible to determine age directly from the fossil. Other times, a fossils age can be determined indirectly. Indirect dating The first is known as relative or indirect dating. By determining the age of the surrounding rock, scientists can give an approximate age to the fossils therein. Rocks are dated by their distance from the surface, with older rocks generally deeper from the surface. Using the data from other fossils found in the same rock stratum can also be used to give an approximate date to a new sample.

11 How To Date A Fossil (continued) Direct dating This method is based upon radioactive decay. The spontaneous release of energy and/or particles from the nucleus of an unstable atom (referred to as the parent) into a stable atom (referred to as the daughter) is radioactive decay. This rate of decays occurs at a specific and constant rate. The age of a rock can be determined by measuring the amount of the daughter product and adding that to the amount of the remaining parent material. This method is known as absolute dating or direct dating. By measuring the ratio between the radioactive forms of an element like uranium 238 to its nonradioactive, "decayed" form, scientists can determine when the rock formed, because that would be when the radioactive isotope was acquired.

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