Station Activity: Fossils
Information Station
Students will read a passage and then complete a task to help increase science literacy and deepen their understanding of the science concept.
Observation Station
Students will have images, illustrations or actual samples that show application or processes. They will need to apply their observational skills to complete questions.
Calculation Station
Students use math skills such as graphing, analyzing data, measurement or calculating using formula
Investigation Station
Students will work with one another to explore concepts through hands-on activities/lab work
Communication Station
This could involve students in a number of different activities – interviews, videos, making posters or brochures or essays. It is about communicating in different ways to show what they know.
Creation Station
Students create models or designs to solve a problem – a STEM type activity
These station activities could form the basis of a DBQ with a culminating writing task. Alternatively they could be used to allow students to demonstrate their mastery of standards in a variety of ways, using their individual learning styles and strengths.
Information Station
The Formation of Fossils
Fossils are the record of life preserved in monuments of stone. Almost all living organisms can leave fossils, but usually only the hard parts of plants and animals fossilize. Soft internal organs, muscle, and skin rapidly decay and are rarely preserved, but the bones and shells of animals are good candidates for fossilization. Almost no fossil record exists for soft organisms such as jellyfish and worms.
Fossils include the footprints of animals left in soft mud, later to be buried, and turned into stone. In some areas herds of fossilized tracks have been found such as at the Johnson farm in St. George, Utah. One of the more exotic fossils is that of swimming tracks made by animals as they brush against the mud and silt floors of an ocean or lake. Under certain circumstances fossils of animal dung, eggs, and even complete nests with eggs have been preserved in stone.
Fossils are formed in a number of different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock. As the encased bones decay, minerals seep in replacing the organic material cell by cell in a process called "petrification." Alternatively the bones may completely decay leaving a cast of the organism. The void left behind may then fill with minerals making a stone replica of the organism.
Fossils can form in unusual ways. Small bugs or insects can become trapped in tree sap. Eventually the sap hardens and forms the semiprecious material called amber. In some pieces of amber the entombed remains of organisms can be found. Volcanic eruptions can form fossils when animals get trapped in the hot ash flows. In this case, the fossil is a hole in the shape of the animal.
By far the most common fossil remains are those of shelled invertebrate sea loving creatures such as snails, corrals, and clams. These make up most of the fossil record. Plants can leave fossils. In fact coal is the fossil record of whole forests; however, individual plant structures usually do not survive as the plant materials are compressed to less than one hundredth of their original size.
Fossils of land animals are scarcer than those of plants. In order to become fossilized, animals must die in a watery environment and become buried in the mud and silt. Because of this requirement most land creatures never get the chance to become fossilized unless they die next to a lake or stream. Indeed there may be whole species of land animals in which no fossil record has been discovered. We may never know how many and diverse these animals were.
1. Why are there almost no fossils of worms or jellyfish?
2. Describe the basic process of fossilization and the conditions necessary for fossil formation.
3. Why are most fossils those of invertebrates?
4. Why are plant fossils more common than land animal fossils?
Observation Station
Diagram Dating
Date the layers below from oldest to youngest
Describe the geological principles you used to determine your answers.
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Calculation Station
Radioactive Decay and Half-Life
Carbon-14 breaks down or decays at a specific rate. We call this rate the half-life. A half-life is the amount of time it takes half of a radioactive sample to decay to a stable product. Carbon-14 has a half-life of 5,730 years. This means that 1 gram of carbon-14 will take 5,730 to decay to ½ gram of carbon-14. The other ½ gram becomes a stable decay product. After a second half life, half of the ½ gram becomes stable. Therefore, ¼ of the original sample is carbon-14 and the remaining ¾ is stable decay product.
Using Radioactive Decay to Determine the Age of Fossils & Rocks
Scientists study the ratio of carbon-14 to its decay product in fossils to determine how old a fossil is. Studying this ratio helps scientists calculate how many half-lives the fossil or rock has been through. This half-life of carbon-14 is a long time but just right for radioactive dating fossils that are less than 50,000 years old. Scientists can use other radioactive elements found in living things and rocks to date objects that are older than 50,000 years old.
1. Complete the following table
Carbon-14 datingHalf life / Mass of original C-14 / Mass of decay product / Number of years
0 / 1 gram / 0 gram / 0
1 / ½ gram / ½ gram / 5,730
2
3
4
5
2. An isotope of cesium (cesium-137) has a half-life of 30 years. If 1.0 g of cesium-137 disintegrates over a period of 90 years, how many g of cesium-137 would remain?
3. How old is a bone if it presently contains 0.3125g of C-14, but it was estimated to have originally contained 80.00g of C-14?
4. Complete the following table and make a line graph of the data on the chart provided. The result should be a smooth, curving line through all points.
Describe the advantage of using radio-active dating compared to relative age dating using evidence from rock layers.
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Investigation Station: Geological & Fossil History Review Puzzle
Instructions: Cut out the individual squares and then have students match the terms and definitions
Communication Station
Vocabulary words:
FossilMoldCastSuperpositionRelative AgeAbsolute Age
EraEonRadioactive DecayTrace fossilCarbon film
Choose 9 vocabulary words from the list of vocabulary words above and create a vocabulary card with the term, definition in your own words and a visual representation.