Video Tutorial - Mineral Cleavage

Cleavage patterns of breakage develop in response of a mineral to hammering. The property of cleavage is better demonstrated with video than viewed in a static image.

Here's a ready-to-go handout with weblinks, instructions, and a layout for student responses.

Click to download the video tutorial shown below.

An "answer key" is not provided because different instructors may have different expectations of detail and expression for student responses.

Instructions to students include terms typically included in Bloom's Taxonomy so that students may be challenged to employ higher order thinking skills that span multiple cognitive levels.

Instructions to the student:
When a crystal of calcite is broken, it naturally fragments into geometric pieces. You will see these pieces in the videos.

Watch the videos, record observations, then speak with your nearby buddies to discuss and prepare your answers to the following instructions.

video #1:

Observe the calcite crystal as it is rotated. Notice how the crystal faces reflect light.
Describe how the intensity of reflected light changes (the pattern) as the crystal is rotated.

video #2:

Sketch a few of the broken fragments.
Describe shape(s) of fragments into which calcite breaks.
Estimate the number of cleavage directions calcite exhibits.
Estimate angles of cleavage for calcite.
Write a brief statement that explains why calcite exhibits cleavage.

Video Tutorial - Calcite Chemistry

Calcite's dynamic reaction to cold, dilute, hydrochloric acid is better demonstrated with video than viewed in a static image.

Here's a ready-to-go handout with weblinks, instructions, and a layout for student responses.

video by Scott Brande

Click to download the video tutorial shown below.

An "answer key" is not provided because different instructors may have different expectations of detail and expression for student responses.

Instructions to students include terms typically included in Bloom's Taxonomy so that students may be challenged to employ higher order thinking skills that span multiple cognitive levels.

Instructions to the student:
When HCl (hydrochloric acid) is dropped onto a crystal of calcite, a chemical reaction occurs. A typical solution used in this "acid test" is about 10% HCl, which means that about 90% of the solution is water, and the solution is at room temperature. We refer to this solution as "cold, dilute" HCl. Watch the video, record observations, then speak with your nearby buddies to discuss the following questions and prepare your answers to the following instructions.

Observe and describe evidence of the chemical reaction.
Describe the pattern of change of intensity of the chemical reaction throughout the video. Is the intensity about the same throughout? Increasing? Decreasing? Some other pattern of change?
Interpret the change of intensity you observed and described. Can we tell when it ends? Why would the reaction end? What causes the rate of the chemical reaction, as observed, to change during the time of the video?
The bubbles are molecules in the gas (or vapor) phase of matter. Identify the source of the molecules in the bubbles. Interpret the pathway by which these molecules travel from their source into the bubbles.
If you had a 55 gallon drum of acid, what do you think would happen if you tossed this crystal of calcite into it? Support your inference with reasoning and evidence.

Video Tutorial - Mineral Phase Change

Video by Scott Brande. Ice, a solid, is unstable when heated above its melting temperature. Melting is a change of phase from the solid state to a liquid state of matter, as seen in this time-lapse video demonstration. Another Geoshort educational video from Scott Brande.