Mineral Identification Lab

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Objective

SWBAT use a flowchart and various mineral-testing procedures to identify physical properties of unknown mineral samples [Lab]

Big Idea

Students conduct an investigation matching the identity of a mineral to its physical properties.

Lesson Introduction

Welcome to the first lab of the year! This lesson is always a perennial favorite of mine, as it allows students to get their hands dirty (literally) in testing out some mineral samples and putting their heads together to practice what they've been learning about in the classroom for the past few days. Not only is this their first lab this year, it's their first lab in high school! To that point, I also try to frame how science works both in the context of 9th grade and as a budding high school scientist. I introduce them to a laboratory rubric we utilize throughout the year, we transition into our lab groups (a very popular activity in my classroom!), and they get the opportunity to use tools and work together and really self-manage their time and processes. Below, you'll find the materials I use for the lab, as well as some thoughts on how I set it up, execute it, and get students to think about it. 

As a quick materials and lab note, while many, if not all of the minerals here can be substituted or changed, that would also change the minerals featured in the flowchart in this lesson. The lab itself requires a fair amount of time for setup, so make sure you have enough time to set up appropriately (i.e. I wouldn't wait until the morning of to set up). Also, students should come in with a fair amount of knowledge on how to conduct hardness tests and the various physical properties of minerals. This lesson does not function optimally as a discovery/explore lesson. Additionally, many of the minerals you see here are relatively common and inexpensive, they're available from most science supply depots and retailers. Below, you'll find a list of specific materials per group (I have groups of 4):

  • Mineral Samples (8-12)
  • Mineral Flowchart
  • Piece of Glass*
  • Penny*
  • Steel Nail*
  • Streak Plate
  • Diluted acid (or a weaker acid like citric acid)**
  • Magnet**

*These are used for testing hardness, but can be substituted for other materials if preferred.

**Only needed if testing for magnetism or performing an acid test (not necessary in many cases)

Do Now & Objective(s)

10 minutes

Students come in silently and complete the Do Now. After time expires, we collectively go over the responses (usually involving a series of cold calls and volunteers) before I ask someone to read the objective for the day.

Laboratory Rubric and Lab Practice

10 minutes

After the objective is read, each student is given a copy of the Lab Rubric, which is a a rudimentary rubric used as a basis for evaluating student performance during laboratory activities. Since this is the first lab we conduct as a class, I try to give them a solid 3-5 minutes to comb over the rubric and identify specific content or process areas. I then spend 2-3 minutes previewing the general overview of science as it works in high school - as a continuation of developing deeper and more complex laboratory process, content, and social skills. For them, many of them have worked with laboratory rubrics in middle school, but this version for early high school students is a bit more advanced and slightly more rigorous. In that sense, I allocate time at the end of the lab for them to self-reflect and think constructively about how they did. They rate themselves on the rubric, and I generally take the "lowest" row from the cohort and prioritize that skill in debriefs and future laboratory conferences with groups. 

[Note: While I do generally grade this rubric in the traditional sense, these grades are not officially recorded in the grade book. While I don't tell students that, I do definitely give them individual feedback this time on their scores if I feel that their self-evaluation is significantly higher or lower than mine.]

Laboratory Introduction

7 minutes

To connect the laboratory activity to previous lessons, and to get students to start thinking (and working) together, I pose the initial question ("Where do minerals come from?") for students to throw around and answer. Again, I'll usually give them a minute or so to talk amongst their lab groups, and then we'll expand the discussion to the entire class. I usually "cold call" on a specific group member, ask what they've discussed, and then check in with another group to see if they agree or disagree. 

[Note: Ultimately, minerals generally come from the cooling of magma or via formation as precipitates, but I generally prod (and may give some hints) to help students reach this conclusion for themselves. It's okay if they're not getting it right away! This group activity is meant to be challenging and to get them thinking critically together. Some questions to guide them or get them on the right path if they're off track are below:

  • "So, give me an example of a mineral." [Answers may vary - Gold, Pyrite, Quartz, etc."
  • "Where do minerals come from. Where are they found?" [The Earth/ground/underground, etc.]
  • "How did the minerals get there?" 
  • "Are there minerals in rocks? How do rocks form? [Our students have been taught the rock cycle before]

 

After this, I'll usually very quickly go over the laboratory procedure (or have students read it in their groups) and answer any outstanding questions. I then do some brief checks for understanding to make sure that students are clear on the directions, rules, and noise level for the activity, and then I let them start collectively. 

Mineral ID Lab

20 minutes

Students are given this time to fill out the Mineral ID Chart, with the help of the Mineral Flowchart. [Note: You may need to modify the flowchart (or create your own) to fit the needs of your class]

Since it's the first time in a laboratory setting, and it's the first lab of the year, I try to check in frequently with each group in terms of their process and logical thinking. I want to ensure all of them are thinking (and acting) productively to get everything done in the allotted time. Usually, I do an initial lab or two just to make sure everyone has all the requisite materials and has gotten started. Once the basic compliance piece is met, I begin to check in with particular groups to encourage them to: make sure they've decided on a group working strategy (How are they working together? Who is deciding to do what, and how?), are actually performing the procedure correctly (Are they doing the hardness test correctly? Are they "on track" in identifying the minerals?), and are getting full input from all laboratory members. Once the lab starts, I give them the flowchart and the mineral kits to work with, so they should be testing and identifying minerals simultaneously. Once the students have performed the tests on the mineral, they use the flowchart to identify it and write down the mineral name in the Mineral ID Chart

Clean Up, Evaluation, & Closing

10 minutes

As noted in the reflection, clean up time is essential. Usually, I give specific instructions on how students can clean (for example, asking one student to wipe all the desks with Clorox Wipes while the "Materials Managers" put away and organize the materials) or assist, but I always leave at least 5-6 minutes for it to actually happen. 

In terms of the laboratory discussion and conclusion, additional time is usually given in the next day's class, or the assignment is given for homework. Even so, it's definitely important to follow up with students (see next lesson here) as a class on the challenges, successes, and key takeaways from the laboratory activity. 

As a final note before dismissal, I reference the Lab Rubric and give students 2-3 minutes to rate themselves on it. This is their "exit ticket" for the class period, and will serve as a functional basis for additional rubric ratings later on in the course.