Weathering STEM activities:

You will need to create your own lab sheet!!!!

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.

Access to a freezer is needed.



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 on Rocks:   


You will need eight 50 ml beakers.

Add 25 ml of water to four 50 ml beakers and 25 ml of vinegar to four more beakers.


Now put a few small pieces of granite in a water beaker and a few pieces of granite into a vinegar beaker.  Now use another beaker for each of the other types of rock and do the same with the other types of rock.  


Type of rocks:  granite, marble, limestone/chalk, sandstone  

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. Ice Wedging Simulation:

Procedure:  Get a 20 oz plastic cup, a 100 ml beaker, a spoon, a balloon, plaster, and water.


  1. Fill the beaker with plaster.  Slowly add water to the plaster and stir constantly until smooth.  Be careful not to add too much water.  If your plaster is too thin, call Mr. B.  

  2. Fill the balloon with water until it is just large enough to fit inside the red cup. Make sure the balloon will fit inside the cup and then tie the balloon shut.

  3. Pour about ⅓ of the plaster into the red cup.

  4. Put the balloon into the cup and pour the remainder of the plaster on top of the balloon.  It should cover the balloon completely.  

  5. Set the cup aside until the end of the period so that the plaster can harden.  Before you leave class, put your cup into the freezer and leave it overnight.


  1. Day 2: Check you cup and write down your Observations and Conclusions:

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

Fill two small cups with vinegar and add either pennies or chalk.  Time the activity and write down your observations.  


Type of Vinegar

Immediate Reaction

After 5 Minutes

After 20 Minutes

Pennies




steel wool




chalk





Observations and Conclusions:


4. Does rock or sediment size affect speed of weathering?

Need two 50 ml beakers.  Get two antacid tablets.  Leave one whole and place the second one into a ziplock plastic bag.  CRUSH! the tablet in the bag.  Place the whole tablet into one beaker and put the crushed tablet into the other beaker.  Carefully pour 25 ml of water into each beaker and write down your observations in the table below.  


Tablet Composition

Immediate Reaction

After 10 Minutes

Whole





Crushed






What were the differences between the two beakers?



What does this tell us about weathering of rocks?  




Observations and Conclusions:  


Your Turn:  Can your team come up with some other ways to demonstrate weathering?