Unit E Review

Key Ideas   Unit Checklist

  Review

On the next page, you will take a 35-question unit test. Are you confident you know the Unit E material well?
It's always a good idea to make sure you are prepared for a test by studying. You can do this by returning to the Table of Contents and reviewing any Unit E lessons you are not sure about.

Also, you can review unit E material by trying three review exercises.

  1. Create a mind map of the unit material. A mind map is a visual representation of how all the ideas and concepts of the unit connect with each other. Try building a mind map by clicking the first tab below.

  2. Do a puzzle! A puzzle can be a fun way to review unit concepts or terms. Try the puzzle we have prepared for you by clicking the second tab below.

  3. Practice answering some questions. We have prepared some questions that will really get you thinking about the unit material. Try the practice questions by clicking the third tab below.

Remember, these are just suggestions for review! In addition to doing these three review exercises, you might also:

  • Contact your teacher for assistance if you are not sure about any concepts.
  • Check the course glossary and read all the unit E terms.
  • Make your own study cards and test yourself.

Whatever you choose to do, good luck with your unit review!

Create a Mind Map
A mind map is a visual representation of how all the ideas and concepts of the unit connect with each other. There are several ways you can create a mind map:

  • You can create a mind map simply with just a pen and a sheet of paper.
  • You might try to build one using a free drawing program such as gimp.
  • You can use a web-based free mind map generator such as mindmup. Mindmup is pretty easy to figure out just by playing with it, but click here if you want to view a short tutorial.

As an example to get you started, below you will see the start of mind map for Unit E that was built using mindmup. You can re-create it and build on it, or create a completely new one of your own.

Unit E Example Mind Map

Do a Puzzle!
A puzzle can be a fun way to review unit concepts or terms. We have prepared a Unit A review puzzle for you:




Try Some Practice Questions
The following 5 questions are meant to get you thinking about the Unit D material. Answers are provided below each question, but before you look at the answer, you should really try hard at answering the question yourself. If you have to, review the Unit D lessons.
Question 1
2 marks

People have been fascinated by Mars for centuries. Probes were sent to Mars 50 years ago. Every probe that has visited Mars has noted that the planet has a very weak magnetic field compared to Earth. This is strange because, although Mars is smaller than Earth, it is thought that the two planets are made up of roughly the same types of materials and that they formed in similar ways 4.6 billion years ago.
 

 
Based on the facts that the two planets should have formed in similar ways and that Mars has a weak magnetic field, suggest two ways that the inside structure of Mars might be different from the inside structure of Earth. Explain your answers.

KEY: 2 marks total

Sample answers:
  • A weak magnetic field is probably due to a solid outer core. It is the liquid outer core on Earth that gives a strong magnetic field.
  • The materials inside Mars might not have settled in the same way. Earth’s magnetic field is due partly to heavy, magnetic materials settling in the core.
Question 2
4 marks

Alfred Wegener and Tuzo Wilson are two famous scientists who studied Earth.
 
Using the ideas from these two scientists and your own thoughts, explain the similarities and differences between the terms “continental drift” and “plate tectonics”.

KEY: 4 marks total

 Sample answers:
  • Wegener suggested the idea of continental drift to explain the shapes of the continents, as well as the fossils, landforms, and fossils that were found far from each other.
  • Continental drift explains how the continents move around on Earth’s surface, sometimes crashing together to form supercontinents.
  • Wilson suggested the idea of plate tectonics to explain hot spots such as the one that formed the Hawaiian Island chain.
  • Earth’s crust is made up of many pieces, similar to a 3D puzzle in the shape of a sphere. These pieces are tectonic plates.
  • The idea of plate tectonics includes oceanic plates; this idea helps to explain how continental drift occurs.
Question 3
8 marks

Imagine four rocks sitting around having a conversation about themselves. The four rocks are basalt (an extrusive igneous rock), gabbro (an intrusive igneous rock), gneiss (a metamorphic rock), and breccia (a sedimentary rock).


Photos by Julian Gray, Rice NW Museum of Rocks and Minerals.

What might the three rocks say to each other that helps to explain what they are and where they came from? You may answer this question using lists of things each would say to the others, or you can write your answer as a series of statements in an ongoing dialogue between the three rocks.

KEY: 8 marks total

4 marks for a description of each type of rock, and 4 marks for an explanation of the origin of each rock type.

Sample answers:
  • basalt (an extrusive igneous rock): Extrusive igneous rocks form from lava that cools above Earth’s surface. The lava cools fast, so the grains in the rock have little time to form and tend to be small. This makes extrusive igneous rocks look smoother than extrusive igneous rocks are.
  • gabbro (an intrusive igneous rock): Intrusive igneous rocks forms from magma that cools below earth’s surface. Intrusive igneous rocks cools more slowly than extrusive rocks do, so their grains have time to form larger. This often makes intrusive igneous rocks have a rougher looking surface than extrusive igneous rocks have.
  • ORIGIN of igneous rock (applies to both basalt and gabbro): All igneous rocks form where temperatures and pressures become so high that the solid rock melts, and its minerals mix together with all other minerals in the melted magma.
  • gneiss (a metamorphic rock): Metamorphic rocks form when rocks are exposed to large amounts of pressure and the heat from magma without actually melting to become magma themselves. The minerals and structure of a rock will change when exposed to large amounts of heat and pressure.
  • ORIGIN of metamorphic rock: Any rock, including a metamorphic rock, can change to become a new metamorphic rock.
  • breccia (a sedimentary rock): Sedimentary rocks are a composite of particles.  Sedimentary rocks take a very long time to form. They also can contain fossils.
  • ORIGIN of sedimentary rock: Sedimentary rocks form from the sediments that are weathered and eroded from all kinds of rocks.
Question 4
4 marks

A challenge is given at a geology camp to determine the correct order of five unknown minerals from hardest to softest. You are given the five unknown minerals; there is no reference chart or any other tools available to you.
 
Describe how you and your team would devise a test to determine the order of the mineral hardness. What is the name of the scale that is used to measure mineral hardness? If you could choose one item (that is not a book, computer, or other reference source) to help you give the minerals an actual value for hardness, what would you choose and why would you choose that item?

KEY: 4 marks total
  • 1 mark for the test
  • 1 mark for naming Moh’s Hardness Scale
  • 1 mark for choosing an appropriate extra item
  • 1 mark for an explanation for how it would help

Sample answers:
  • One at a time, and keeping track of the results, scratch the minerals with each other. After several trials, it should become obvious which of the minerals is the hardest (scratches the other unknown minerals) and which is the softest (is scratched by the other unknowns).
  • Minerals are rated on Moh’s Hardness Scale.
  • Examples of another item would probably include materials of a known hardness that are near the middle of Moh’s Hardness Scale. This might include a glass plate or nail (hardness of 5.5).
  • If you can test the hardness of the unknowns with one item of a known hardness, you can guess at the hardness of an unknown that is close to your item. After you estimate the hardness of one unknown and you have ranked them all, you can guess at the hardness of the remainder.
Question 5
3 marks

Why would a sea creature such as Perisphinctes, an extinct ammonite sea creature, be used as an index fossil for the Jurassic Period rather than a more famous fossil from that time such as the Stegosaurus? Explain what an index fossil is as a part of your answer.



KEY: 3 marks total

1 mark for an explanation of index fossils
2 marks for supporting examples

Sample answers:
  • An index fossil is a fossil from a living thing that was very common during a certain time on the geologic time scale. Its fossils are found in many places, and its fossils are very distinctive. The organism had a large population, but it did not exist as it is outside this particular time period.
  • When you find this exact fossil, you know the rocks it was found in are from that specific location on the geologic time scale.
  • Usually, more life occurs in water than on land throughout Earth’s history, so many index fossils are from water organisms, not land organisms such as Stegosaurus.
  • Perisphinctes has a shell, and creatures with hard parts leave behind many fossils.
  • Shell design often changes slightly through time. Perisphinctes probably has a distinctive shell design that helps identify its fossils.