Mars for Earthlings > Lesson Modules > In-Class Activity 1- Break a Rock!

Break a Rock!

In-Class Activity 1_Weathering and Soils

Julia Kahmann-Robinson PhD and Marjorie Chan PhD, University of Utah Department of Geology & Geophysics

Purpose

Determine how the physical breakdown of rocks leads to increased rates of weathering and erosion.

Preparation

Depending on class size the following is needed for each student or team of students:

  1. Rock hammers
  2. Rocks (Geodes would be nice! Otherwise, a rock with a weathering rind is good).
  3. Hand lens if possible, but not necessary

Engage

Use the rock hammer and rock provided by your instructor. Break the rock in such a manner that you can see "the middle" of the rock

Explore

Have students make a sketch in each circle below of the outside vs. inside of the rock (respectively). Students should note color changes, sizes of crystals, any mottling etc., and be as observant as possible. Also, they should provide some sort of scale to understand the relative sizes of your sketches.

Mechanical vs. Chemical Weathering

Consider the sketches, do students see evidence for mechanical weathering and/or chemical weathering? Please list them.

Explain

Elaborate

  1. Are there different rates or rock responses to weathering in the picture below? What parts are resistant to weathering and why? Note the scale in the caption.
  2. Have students find an internet image of the weathered accumulations of these "blueberries" from other Opportunity explorations and explain what that that means about how an outcrop would erode over time.

Evaluate

Ask students to list the most important factors in the rate of weathering (name 3 factors).

a)

b)

c)