7.2.3 Geologic Time - Culminating Task

Grade 7

Unit 2.3 Culminating Task

State Standards

SC.7.E.6.3 - Identify current methods for measuring the age of Earth and its parts, including the law of superposition and radioactive
dating.

SC.7.E.6.4 - Explain and give examples of how physical evidence supports scientific theories that Earth has evolved over geologic time
due to natural processes.

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Open Ended

Using the Law of Superposition and other geological principles place the following layers of the geologic column in order from oldest to youngest.  Explain how you did this.

Open Ended

This is an image of four siblings, explain how “dating” these siblings would be different if you use an absolute dating method compared to a relative dating method.

Open Ended

Approximately, how old is the Earth and how did scientists find this out?

Open Ended

Both relative and absolute dating are used to study Earth’s history. Give an example of how both techniques could be used together to date igneous and sedimentary rock that are found together.

Open Ended

What does sedimentary rock tell us about past environments on Earth?

Multiple Choice

In 1997 a team of scientists discovered three fossilized skulls and other artifacts at a dig site in Ethiopia, Africa. Since it is difficult to determine the age of once-living organisms, the scientists used radioactive dating on the igneous rocks that surrounded the remains to determine their age. Why would scientists use radioactive dating in order to determine the age of the fossil they discovered?

• Law of superposition is a more expensive method to apply than radioactive dating for estimating the age of a rock.

• Law of superposition is specific and gives the date that the rock was formed while radioactive dating gives an estimate of the age.

• Radioactive dating gives an estimated date that the rock was formed, while the law of superposition will only reveal which rock is younger or older.

• Radioactive dating determines whether the igneous rocks are older or younger, while the using the law of superposition depends on tectonic events.