Changing Earth EUA Review

Based on the graph, how long is 1 half life for this substance?

• 10 seconds

• 20 seconds

• 30 seconds

• 50 seconds

Answer explanation

To find how long a substance's half life is,

1) Find on the graph how much of the substance you have to start (ex: 100)

2) Find on the y-axis how much HALF (50%) of that substance is (ex: half of 100 is 50)

3) Draw a line from 50% on the y-axis to the line in the graph, then draw DOWN to the x-axis (ex: see the graph- the half-life is 10 seconds)

Based on the graph how long is the half-life for this substance?

• 0 Days

• 4 Days

• 8 Days

• 12 Days

Answer explanation

To find how long a substance's half life is,

1) Find on the graph how much of the substance you have to start (ex: 16,000 atoms)

2) Find on the y-axis how much HALF (50%) of that substance is (ex: half of 16,000 atoms is 8,000 atoms)

3) Draw a line from 50% on the y-axis to the line in the graph, then draw DOWN to the x-axis (ex: see the graph- the half-life is 8 Days)

Tags

NGSS.HS-PS1-8

The statement that Earth is changing the way it ALWAYS HAS describes what theory?

• Index Fossils

• Absolute Dating

• Climate Change

• Uniformitarianism

Answer explanation

Uniformitarianism is a theory that states that

1) The things that change the Earth today were changing Earth in the past

2) These small changes cauese large changes over long periods of time

Which of the following kinds of rocks have the most preserved fossils?

• Sedimentary

• Igneous

• Metamorphic

Answer explanation

Sedimentary rocks are formed by dirt, mud, dust, and other substances being squeezed together by pressure. When fossils get trapped inside these rocks, they are preserved very well for millions (even billions!) of years

Which of the following is the MAJOR reason fossils are difficult to find in igneous rocks?

• Igneous rocks are made from pressure which squeezes the fossils too hard

• Igneous rocks are made from lava which will destroy the fossils before they harden into rock

• Igneous rocks come from space and smash fossils before they can be preserved

• Trick question: Igneous rocks are great for preserving fossils

Answer explanation

Igneous rocks are formed by hot lava cooling into solid rock- it cannot preserve fossils well because the lava destroys the fossils before they can be preserved

Which of the following rock layers is the youngest?

• A

• B

• C

• D

Answer explanation

The Law of Superposition states the YOUNGEST rock layer will be on top!

Tags

NGSS.MS-ESS1-4

Which of the following rock layers is the oldest?

• A

• B

• C

• D

Answer explanation

The Law of Superposition states the OLDEST rock layer will be on bottom!

Tags

NGSS.MS-ESS1-4

Which of the Brachiopod fossils seen in this image is the oldest?

• 
• 
• 

Answer explanation

Remember, the law of superposition states that the oldest fossils will be found on the bottom layers!

Tags

NGSS.MS-ESS1-4

Which of the following layers is an INTRUSION (a flow of magma that moved up through the rock layers before cooling into igneous rock)?

• A

• B

• C

• D

• E

Answer explanation

An intrusion will always look like a major interruption in the rock layers that came from below- and it is always YOUNGER than the layers it cuts through!

Tags

NGSS.MS-ESS1-4

Which of the following features is younger and how do you know?

• E is younger than D, because D cuts through E

• E is younger than D, because E cuts through D

• D is younger than E, because D cuts through E

• D is younger than E, because E cuts through D

Answer explanation

E is a fault and D is an intrusion, but clearly E cuts straight through D. Therefore, if E cuts D, D must have been there before E, so E is younger

Tags

NGSS.MS-ESS1-4