Last updated: September 10, 2022
Lesson Plan
Sediment Sorting
- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
- Subject:
- Science
- Lesson Duration:
- 60 Minutes
- State Standards:
- Colorado
3rd Grade
o ESS2-1, ESS3-1
4th Grade
o ESS1-1, C
5th Grade
o PS1.1-3 - Thinking Skills:
- Analyzing: Break down a concept or idea into parts and show the relationships among the parts. Evaluating: Make informed judgements about the value of ideas or materials. Use standards and criteria to support opinions and views.
Essential Question
How does sediment size and layering in sedimentary rock describe how a material was deposited?
Objective
Students will demonstrate the geologic process of sediment sorting. Sorting describes how fine to coarse grain sediments are distributed (settle), and how they will eventually lithify into sedimentary rock. Students will mimic sois deposition in a lake setting so as to better visualize the layering of the shale deposits in the Florissant Formation.
Background
Sorting describes how sediments are distributed based on their size.
- Terms describing sorting in sediments
- Very well sorted – sediment sizes are very similar in size within a strata.
- Well sorted
- Moderately sorted
- Poorly sorted
- Very poorly sorted – sediment sizes vary largely and are mixed in sizes (small to large) within a stata (layer).
- Degree of sorting indicates the energy, rate, and duration of deposition and how the sediments were transported (i.e., volcanic debris flow, streams, wind, glaciers, still water etc).
- Sediments can also get reworked after being deposited through a process called winnowing which is the removal of finer material from coarser material.
Preparation
Materials needed:
- Plastic lidded jar
- Sediments:
- Clay/shale
- Sand
- Silt
- Gravel (grus)
- Plant material and debris
- Water
- Arrow shaped post-its
- Small containers with lids
- “Sedimentator” sorting tube
- Rock sample boxes
- Sorting & grain size chart
- Assessment materials enough for each group
- Stopwatches
- Beakers
- Pitchers
- Small scoop
- Pencils
Preparation
- check activity and general supply kit bins for sufficient reusable supplies: soils, post-its, pitchers, beakers, etc
- make copies of assessment materials and sorting images, if necessary
- arrive to location early enough to prepare experiment tables for each group: small cups of soil samples, beakers, etc.
Materials
Download Sorting and Grain Size Chart
Lesson Hook/Preview
Lakes are home to an abundance of plant and animal life but can be “home” to an abundance of geologic stories also! Particles of soils, minerals, and rocks can be described by their size and shape as well as by how the materials form sedimentary layers. The layers, or strata, are deposited in lakebeds in known patterns called sorting. Students will mimic the action of sediment sorting as it occurred in Ancient Lake Florissant using differing sizes of sediment materials mixed inside lidded jars.
Procedure
Procedure
- Have students separate into small groups of 4 or 5.
- Give a brief lesson on sediment sorting and the purpose of this experiment—use Sedimentator Sediment Tube to show process. Students may enjoy a demonstration by you of the experiment, with explanations of each step, before they begin their own experiment. (page 2 “Lesson Hook and Background”)
- Work with the class to answer assessment question #1.
- Give each group a lidded jar, a stopwatch, sharpie, pack of sticker arrows, and small sample cup of each type of rock and plant material.
- Have students take turns pouring all the sediments together inside of the plastic jar. The jar should be about ½ full but no more than 2/3 full.
- Give students a beaker of water. They will add enough water to the soils for the jar to be approximately ¾ full, but no more. Jars will need a bubble of air to facilitate mixing. Have students screw the lid tightly back onto the jar. Double check lid tightness of each jar for the students!!
- Have students take turns shaking their group’s jar. They can use the stopwatch to ensure the jars stay in motion for a minimum of 2 minutes.
- As soon as students are done shaking the jar, have them place it onto a flat surface then start the stopwatch.
- In the space for question #2, Record the time in which the first sediments begin sinking to the bottom of the jar, Record times for each additional layers as they begin to form.
- After seeing distinct layers in the jar, students will place an arrow sticker at the point of each visible layer.
- Write observations in question #3 for the first layer, describing the size of the sediments.
- Work with the class to make observations about each layer. Make notes in question #4.
- Discuss observations with students and work as a group to answer question #5.
Vocabulary
- Sediments
- Sedimentary rock
- Lithification
- Deposition
- Fine-grained
- Coarse-grained
- Sorting
- Graded bedding
- Rounding
- Porosity
Assessment Materials
Sediment Sorting Assessment- Describe a natural action that can lead to sediment sorting. Would you expect your example be very poorly sorted or very well sorted or somewhere in between? Why?
- Time sediments began sinking:
- Describe which sediments formed the first layer. What was the size, shape, or name of the material?
- How many layers in total formed inside the jar? How would your rate the quality of sorting that happened in this experiment?
- Based on the layering of the sediments in the experiment jar, can we determine what type of environment the jar is intended to represent?
Rubric/Answer Key
- Examples can include flowing rivers, wind, volcanic debris flows, etc. Students can have many answers that should include the idea that increased energy into the deposit means less sorting will occur.
- Times will vary. Students may struggle with when to record a time as they may not expect the sinking to be quick or may expect very distinct layers. Take an average time for the class for each layer and discuss how or why some sediments settled quickly while others remain in suspension.
- Gravel, sand, clay, silt, with plant materials scattered throughout the layers. Students will notice that layers are not distinct stripes. Clay and silt may be difficult to see or tell apart, but the silt will remain in suspension. Students should describe each type of material as best as they can using words that involve comparative size and weight.
- The number of layers formed should be the same number as the different layers of sediment added: 5. The layers separate based on the size of the sediments making up each layer, with the bottom layer being the heaviest and larges. Not all layers will be perfectly formed and some materials, like the plant debris, will be mixed throughout. This could be described as moderate to well sorted.
- We know the layers were formed in a low energy environment because the jar is an closed space where the only energy available is what we put into it. The rock layers form as the sediments settle to the bottom, which occurs as soon as we stop putting energy into the enclosed environment. This describes any naturally occurring environment where intense energy my cause the sediments (such as a volcanic eruption) but the intense energy is brief and allows settling of materials into a mostly sorted pattern. This is consistent with a low energy environment like a still and/or deep body of water.
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Tags: sediment