1. put safety quiz, safety contract, and donorschoose form (if applicable) in front of you. i will...
TRANSCRIPT
Catalyst
1. Put Safety Quiz, Safety Contract, and DonorsChoose form (if applicable) in front of you.
I will check them off.2. Catalyst Question: Based on the
four characteristics of minerals, how do you think geologists identify different minerals?
Agenda
Catalyst Announcements Mini-Lesson: Identifying Minerals Lab: Geologist for a Day
Alternative: Mineral Packet Work Time (Foldables) Closing Exit Ticket
Foldable
Be sure that by the end of class on Thursday (10/25) you have completed your foldable on silicates, carbonates, and oxides. I will be collecting/marking them. Only
marked foldables may be used on the quiz.
If you were absent, see me during work time.
Science Fair Part 2 (100 points)
Up to 90% credit today Be sure to stay up-to-date!
Identifying Minerals
Objective
By the end of class, CWBAT create a lab procedure to determine the identities of unknown minerals.
CCSS Reading Grades 11-12▪ Follow precisely a complex multistep procedure when carrying
out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.
CRS Scientific Investigation: 28-32▪ Determine the hypothesis for an experiment.
Assessments:▪ Assessed in creation of lab procedure/completion of packet.
Basics
More than 3000 minerals in Earth’s crust
How do you identify so many? Use a
combination of tests!
Tests
1. Color2. Luster3. Texture4. Streak5. Hardness6. Cleavage/Fracture7. Density/Specific Gravity8. Special Properties
1. Color
Most noticeable characteristic
Can be due to the presence of trace elements Quartz types▪ Rose quartz (pink) contains
manganese or titanium▪ Jasper (red) contains iron oxides▪ Amethyst (purple) contains
ferric iron▪ Citrine (orange) contains iron
hydrates All of these are quartz!
The least reliable way to identify a mineral
These all have the same chemical
composition , they just contain different trace
elements!
2. Luster
The way a mineral reflects light from its surface.
Described as either Metallic Nonmetallic
2. Luster
METALLIC
Shiny; reflects like chrome on a car
Examples: Copper, silver, gold,
galena
NONMETALLIC
Not shiny; described as dull, pearly, waxy, or silky
Examples: Calcite, gypsum, sulfur,
quartz
3. Texture
How a mineral feels to the touch
Descriptions: Smooth Rough Ragged Greasy Soapy Glassy
4. Streak
The color of a mineral when it is broken up and powdered.
Determine by rubbing across an unglazed porcelain plate Will not always be
the same as the external color!
5. Hardness
Measure of how easily a mineral can be scratched
Mohs Scale of Hardness Based on known hardness of 10 minerals▪ 1: Talc (scratched by fingernail)▪ 10: Diamond (scratches all common objects)
One of the most useful tests
5. Hardness
copper coin
the side of a steel nail
Leaves mark on a streak plate
6. Cleavage & Fracture
How minerals break is determined by atomic arrangement. Minerals split along planes where atomic
bonding is relatively weak.
6. Cleavage & Fracture
Cleavage A mineral has
cleavage when it splits relatively easily and evenly along one or more flat planes.
Examples:▪ Mica▪ Perfect cleavage in
one direction
▪ Halite▪ Cubic cleavage
(breaks in 3 directions)
6. Cleavage & Fracture
Fracture When minerals
break with rough or jagged edges
Examples:▪ Quartz▪ Uneven breaks along
jagged edges due to tightly bonded atoms*
▪ Rock obsidian▪ Conchoidal fractures
(arc-like patterns resembling clam shells)
7. Density & Specific Gravity When you lift two equally-sized
minerals and one feels heavier. Density
D = M/V Reflects atomic weight and structure of a
mineral Specific Gravity
More accurate than estimates of density S.G.= weight of substance/weight of equal
volume of water at 4°C
8. Special Properties
Double refraction Causes 1 ray of light to bend
in 2 directions Calcite, Iceland spar
Reaction with HCl Reaction creates bubbles of
CO2 Calcite (calcium carbonate)
Magnetism Acts like a magnet Magnetite, lodestone
Odor Rotten egg smell Sphalerite, sulfur
Volunteer needed!
Lab Instructions
Contacts out Hair tied back Absolutely NO
Gum Food Drinks (even water!)
If you did not turn in your forms, gather near the whiteboard for further instructions.
Lab Instructions
1. Read pages 92-93 Silently/independently
2. Groups of three 1) Supervisor▪ Gathers materials/responsible for directions being
followed▪ Leads group through experiments
2) Data Manager▪ Create chart/write
3) Primary Experimenter▪ Carry out tests▪ Acid, nail, etc.
Lab Instruction Changes
On sheet in basket: Magnifying glass (x1) Add “Paper clip (x1)
Lab Instructions
Answer Questions: Plan the Experiment▪ #1, 3, 4
Analyze▪ #1-4
Make sure that you have a hypothesis, chart, and write-up of the questions.
When finished, raise your hand.
Work Time: Foldables
Use pages 81-83
Review Objective
By the end of class, CWBAT create a lab procedure to determine the identities of unknown minerals.
Exit Ticket
On the back of your Catalyst sheet…
What are the most reliable ways to determine the identity of a mineral sample?
What are the least reliable ways?