Investigating Processes of Sedimentation in Gravel Pits
Summary
In this field investigation, students will investigate processes of deposition that have contributed to the current Minnesota sediments and landscape. After learning about weathering and erosion and having a short introduction to depositional processes, students will explore a local gravel pit for the composition of the material and also any layering or observable difference. Students will make observations at the site, as a class we will discuss findings and possible explanations for the observations. Student will have to develop a plan to determine how the sediments were deposited. By the end of the lesson, students will be able to compare and contrast the many modes of deposit for glaciers and water.
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Learning Goals
One of the main learning goals for the activity is for students to further develop their observation skills and be able to develop questions they can investigate from those observations. This is an important part of the scientific method that should be done often to develop these skills. Through their observations, students will learn about the sediments that cover Minnesota and the processes that deposited them there. There will analyze the area and determine which process where involved in the deposition of the sediments. Though not the main focus, other ideas that might be addressed through their observations may include bedding and other depositional environments.
Key Concepts:
o The processes of glacial and hydrological deposition produce different compositions of sediments and occur in different environments.
o Both hydrological and glacial process played a role in developing the current sediments in Minnesota.
o Different deposition events will create layers with different compositions and chractistics.
Vocabulary:
Key Concepts:
o The processes of glacial and hydrological deposition produce different compositions of sediments and occur in different environments.
o Both hydrological and glacial process played a role in developing the current sediments in Minnesota.
o Different deposition events will create layers with different compositions and chractistics.
Vocabulary:
-Outwash
-Till
-Bedding
-Clastic sediments
-Weathering
-Erosion
Context for Use
This activity is going to be used in an 11-12 grade Earth Science class of 25 to 30 students, but could be easily adapted for other grade levels and classes sizes. This activity will take one 90 minute block for introduction and preparation, a half day for the field work (180 minutes), and one 90 minute block for wrap up. Be sure to contact the owner of the gravel pit the class will visit and also explore the site before the activity. The day of the investigation, a box of supplies that students can utilize for observing and exploring is helpful. Things that could be included: hand-lenses, jars, small shovels, maps of the area, and water bottles. It is important for students to have a basic understanding of weathering, erosion and deposition before doing this activity. Within my curriculum this activity will be within my rock unit, when we explore the portion of the rock cycle that occurs on the surface.
Description and Teaching Materials
Day 1: On day one, the concepts of weathering and erosion will be introduced. Students will start by taking a pre-test. Then they will read a section from their text book on weathering and erosion. Students will complete a Venn diagram comparing and contrasting the two processes. Class discussion will take place about how and when these processes take place, but also their importance and role on Earth. Next students will explore and discuss the types of weathering, chemical and mechanical, in a similar manner. Demonstrations of weathering actions could accompany this section. Lastly for the day, students will be introduced to the four major modes of erosion. They will have to draw pictures of each method and make predictions of the types of sediments they deposit. To wrap up the day clear expectations for the following day are set. They will be expected to actively take part in observations, discussions, and explorations. Students will be required to do a write up following field investigation.
Day 2: Students will meet before leaving of a more in depth description of what they are expected to do upon reaching the gravel pit. Then students will board the bus for the trip. Once at the destination students will have about 20 minutes to make at least 20 observations with their partner. As they explore, move about the groups, answer questions as vaguely as possible or ask questions in return to get students to think about what they are seeing. Then gather the students for discussion. Begin the discussion with what they observed. From there let the students observations guide some of the discussion, but in the end ask the question "how did the material get here?" Allow of an answer then lead to "how do you know?" and "how can we test it?" At the end of the discussion students will be tasked with coming up with a way to test their ideas of how it got there. They will be able to collect samples, look closer at things, look at topographic and geological maps, or what ever they need to answer the question. They can use what ever they would like from the bucket of supplies to help them out. They will also get a little time back at school and the next day to complete experiments if necessary. Note: Other topics may come up in discussion, which is wonderful. Discuss them, but in the end come back to depositional processes.
Day 3: Allow students to have time to wrap up experiments and/or work on writing their papers. After a fair amount of time, discuss with students their findings and their potential meanings. In the end go back to students predictions about sediment deposition and explain each process in more detail.
The following day the post-test will be given. This lesson will also be followed up by a lesson about each of the four major erosion processes in more detail and also sedimentary rocks.
Day 2: Students will meet before leaving of a more in depth description of what they are expected to do upon reaching the gravel pit. Then students will board the bus for the trip. Once at the destination students will have about 20 minutes to make at least 20 observations with their partner. As they explore, move about the groups, answer questions as vaguely as possible or ask questions in return to get students to think about what they are seeing. Then gather the students for discussion. Begin the discussion with what they observed. From there let the students observations guide some of the discussion, but in the end ask the question "how did the material get here?" Allow of an answer then lead to "how do you know?" and "how can we test it?" At the end of the discussion students will be tasked with coming up with a way to test their ideas of how it got there. They will be able to collect samples, look closer at things, look at topographic and geological maps, or what ever they need to answer the question. They can use what ever they would like from the bucket of supplies to help them out. They will also get a little time back at school and the next day to complete experiments if necessary. Note: Other topics may come up in discussion, which is wonderful. Discuss them, but in the end come back to depositional processes.
Day 3: Allow students to have time to wrap up experiments and/or work on writing their papers. After a fair amount of time, discuss with students their findings and their potential meanings. In the end go back to students predictions about sediment deposition and explain each process in more detail.
The following day the post-test will be given. This lesson will also be followed up by a lesson about each of the four major erosion processes in more detail and also sedimentary rocks.
Teaching Notes and Tips
This is very different they anything I have done before. Some things that I, at this point, think are important to consider are finding a great location and setting expectations. There are gravel pits all over, but not all are good for fieldtrips or are accessible. It is important to get into the pit beforehand to make sure it will work for your purposes. Also, finding an owner that will help you is a bonus. Finding a location that is close to you is also important to help control transportation cost and the amount of time students are out of the building. The most important thing I think to consider is setting very, very clear expectations for the students. Students need to know what they will be expected to do at the location and also what the consequences will be if they do not meet expectations. To help students understand the process, if a similar lesson can be on a different topic in a more controlled environment, that would be great.
Assessment
Students will be assessed using many different methods throughout and after the activity. First off, I will use a pre-test to determine knowledge on the topic before beginning the lesson. The same post test will be given to help gauge what they learned. During the activity, their observation notes and discussion will help to determine understanding. To wrap up the activity students will complete a one to two page summery of the investigation and what they have learned. Lastly, as part of the unit test, there will be a question where they will have to analyze sediments to determine the transportation method and also a question comparing and contrasting deposition processes.
Standards
9-12.III.A.5 Weathering and Erosion
9-12.III.A.6 Rock Cycle Processes
9-12.III.A.6 Rock Cycle Processes