Weathering STEM activities

Weathering  refers to the group of destructive forces that change the physical and chemical character of rock near the earth’s surface.

Mechanical weathering (or physical disintegration) is the breaking down of rocks into smaller pieces.The change in the rock is physical with little    or no chemical change. Examples of mechanical weathering include:

frost action, abrasion, and pressure release.

Chemical weathering is the decomposition of rock from exposure to water and atmospheric gases (mainly carbon dioxide, oxygen, and water vapor). As rock is decomposed by these agents, new chemical compounds form.  Examples of chemical weathering include:rusting, acid breakdown, and solution weathering.


Erosion  is the picking up or physical removal of rock particles by an agent such as streams or glaciers. Weathering helps break down a solid rock into loose particles that are easily eroded. Most eroded rock particles are at least partially weathered, but rock can be eroded before it has weathered at all. A stream can erode weathered or unweathered rock fragments.


Materials/Preparation: Preparation for this is general lab preparation. This can be done as a series of stations.

Weathering Activities:

You have learned about the two types of weathering. Review the differences between the weathering with your teammates.

Perform the following weathering activities.

  1. Effects of Water and acid on Rocks:   

    You will need eight small plastic bottles, some chips of granite, chips of sandstone, chips of marble, and chips of limestone, some vinegar and water.

    Put a couple ofsmall pieces of granite in two bottles.  Now do the same with the other rock samples, two chips per bottle. 

    Now make two sets of bottles. Each set should have one sample of each of the rocks.  In one set of bottles, add enough water to cover the chips.  In the other set of bottles, add enough vinegar to cover the chips. 

    Using the red timer, observe the different types of rock in both water and vinegar for 10 minutes and then 25 minutes.  Write down your observations in the chart below.

    Observations:


    Solvent

    After 10 Minutes

    After 25 Minutes

    Tap water/ granite



    Tap water/marble



    Tap water/limestone



    Tap water/sandstone



    Vinegar

    AFTER 10 Minutes

    After 25 Minutes

    granite



    marble



    limestone



    sandstone




    Observations and Conclusions:




2. Effects of vinegar on pennies, steel wool, and chalk

Fill three small cups with vinegar and add pennies to one cup, chalk to another, and steel wool to the third.  Time the activity and write down your observations.  


Type of Vinegar

Immediate Reaction

After 5 Minutes

After 20 Minutes

Overnight

Pennies



 

steel wool



 

chalk



 

Observations and Conclusions: