KH Sci Tri 1 fin

Jacob has one older brother and one younger sister. He wants to explain relative dating to them using their ages as an example. Which statement describes their ages using relative dating?

• Their ages are 14, 12, and 9

• 1. They are all about the same age.

• The boys have different ages from the girl.

• Jacob is younger than his brother but older than his sister.

The diagram shows one kind of radioactive decay that is used for dating.

Which statement best describes what information is needed to determine the age of a rock sample using this type of dating method?

• the exact mass of uranium-238 in the sample

• 1. the amount of lead-206 present in the sample

• 1. the energy being released by the uranium-238

• the relative amounts of uranium-238 and lead-206

Which method of finding the relative age of rocks do scientists often use?

• Igneous rock is older than nearby sedimentary rock, which is older than nearby metamorphic rock.

• Metamorphic rock is older than nearby sedimentary rock because sedimentary rock is deposited before metamorphic rock forms.

• The exact age of a sedimentary rock layer can be found using the layers above and below it, even if the layers are not in their original positions.

• A sedimentary rock layer in its original position is older than the layers above it and younger than the layers below it.

Earth is approximately 4.6 billion years old. How do scientists determine this?

• measuring the age of the oldest fossils

• 1. measuring the age of the oldest glaciers

• 1. using absolute dating techniques on meteorites

• determining the chemical composition of sea-floor sediments

Which statement best describes an index fossil?

• 1. a fossil of an animal captured in ice

• a fossil of an insect captured in amber

• a fossil used to establish the absolute age of a rock layer

• a fossil formed in soft sediment by the movement of an animal

Basalt is a gray or black igneous rock. Pilar uses an absolute dating method to study a sample of basalt. Which phrase indicates the age of the rock in years?

• half-life of the rock

• absolute age of the rock

• radioactive date of the rock

• age of the index fossil in the rock

The diagram shows rock layers that are cut by a fault and two bodies of rock (Rock 1 and Rock 2).

What are the relative ages of the features in order of oldest to youngest?

• Fault, Rock 1, Rock 2, Layer 1

• Layer 1, Rock 2, Rock 1, Fault

• Fault, Rock 2, Layer 1, Rock 1

• Rock 2, Layer 1, Rock 1, Fault

Explain how absolute age of volcanic ash and relative age can be used to help scientists find the age of fossils.

Scientists have determined the ages of rock samples from other places in the solar system.

What is one type of extraterrestrial rock for which scientists have determined an absolute age?

Explain how an index fossil record can be used to help determine the age of other fossils.