Weathering and Erosion

 

This week, Girlstart students (and future geologists!) reviewed physical weathering, chemical weathering, and erosion before putting different types of soils to the test!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Before beginning their activity, students worked together to review the difference between chemical and physical weathering. Tables volunteered their ideas, then STEM Crew leaders provided an antacid tablet for girls to observe. Students watched the tablet dissolve in a glass of water and create bubbles as an example of a chemical change. Crew leaders explained that the dissolved tablet had undergone a chemical change. Minerals in rocks can also dissolve – a common example of chemical weathering. On the other hand, physical weathering does not lead to a change in a rock’s chemical composition.

 

 

 

 

 

 

 

 

Girls were then given soil, soil with grass, and sand. Using these materials and a paper cup, students created landforms and weathered them away with water. Because of the loose grains, students found that their sand landforms weathered away more quickly than the other soil types. Finally, students evaluated the significance of their newfound knowledge as geologists. What applications can you think of for this knowledge? Some student answers included protection of homes in floodplains and prediction of landform movement over time.

 

Exploring the Earth

 

During this week’s activities, Girlstart students learned about skills used by geomorphologists, who study geological processes and resulting landforms. Students brushed up on vocabulary that included “deposition,” “erosion,” and “weathering,” then got to work forming their own canyon models!

 

 

 

 

 

 

 

 

 

 

 

 

 

Small groups were given different colors of sand, a tupperware box, and a cup of water to create their miniature canyons. Girls emptied out their first bag of sand in the tupperware box to represent a sea floor. Next, each bag of colored sand was laid carefully on top of another. Finally, girls had a visual demonstration of sediment layers throughout history.

 

 

 

 

 

 

 

 

 

 

 

 

Students used their water cups to create a “river” that eroded the sediments and cut through the many layers. Girls were excited to point out the different colors that were now exposed in the deep canyon, due to the weathering of the rock surface over time.

 

 

Cookie Mining

 

Girlstart students are digging deep and learning skills found in the Petroleum Engineer career! In small groups, students practiced mining for “mineral deposits” and calculating the environmental cost of their excavations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

First, girls timed the process of using toothpicks to “mine” for chocolate chip minerals on the surface of a cookie. After extracting the mineral deposits, students “processed” the valuable resources by separating the chocolate from any cookie crumbs that remained. Each minute spent mining and processing was multiplied by $20 to find the “Mining and Processing Fee.” A “Total Land Damage Fee” was calculated based on the number of broken cookie pieces, and an “Environmental Impact Fee” of $100 was added on top of that. Students realized that mining for mineral deposits is quite expensive! After adding up the value of their mined chocolate chips and calculating their profits, girls recorded their thoughts in their journals. Some groups made a profit, but others went under.

 

 

 

 

 

 

 

 

 

 

 

 

In order to decrease their expenses, girls worked together to strategize. Suggestions included increased mining speed or greater care to avoid breaking the cookie into pieces. Students were also challenged to consider different situations. If the mineral deposit was a nut or a raisin, how would that change the drilling strategy?