Materials Included In Kit

Additional Materials Required

Prelab Preparation

Each particle size should have its own container, with appropriate labels.

Teacher Tips

• Enough materials are given for 30 students working in pairs. This activity may be completed in one to two class periods.
• Particle sizes B, C and F may be used for Activity A as well.
• There is one container of unsorted particles (Particles, size F). This represents “till” or glacial deposits that are unsorted. Student may also identify the various types of particles in this sample.
• Particles “C” and “E” may need to be estimated in size by the students. Unless a micron microscope slide and microscope can be utilized, the students should estimate these small particles to the nearest half millimeter.
• Clay and silt may also be used in this activity. The students can measure these particles fairly well if technology is utilized. Use a micron microscope slide or a microscope hook-up to the monitor. Students can observe the monitor (real-time) and measure the particles on the screen with the micron microscope slide the teacher has set up for the class. Usually, these particles are not well sorted and one slide may have both silt- and clay-size particles.
• Use sand and pebbles that are provided to show the very wide range of sizes for particles we call “sand.” “Pebble” can be quite large (6.4 cm particle). Most people have a rough idea of what to call particle sizes, but these containers (B, C, D and E) should show the range of sizes.

Further Extensions

• Go outside! Have the students pick up particles from outside their school (e.g., roadways, streambeds) to measure and classify. Begin a discussion about other observations they may make at the same time (e.g., texture, color, rounded versus sharp edges, purpose versus size—railroads typically use a specific size).
• Instead of the teacher carrying in a boulder from outside, students can “find” one on the school property and measure it (10-minute class trip).
• Students can be easily reminded of their expertise with particle sizes when the topic of stream deposition and depositional patterns (glacial) is taught during the year. They will come to the topic with prior understanding of vocabulary and the rudiments of particle classification.

Sample Data

Activity B

Answers to Questions

Activity A

1. As soon as the bottle was set on the table, what began to happen inside?

   The water continued to move around, but particles immediately began to sink to the bottom of the container.

2. Draw the sediment pattern.
   {12645_Answers_Figure_1}
3. After most of the motion stopped inside the bottle, what pattern of sediments emerged?

   Large particles settled to the bottom of the bottle first and fastest. On top of those large particles, smaller ones settled, until at the top of the container only the smallest particles (sand) settled out. Some material remains in suspension, leaving the water cloudy.

4. This pattern developed because flowing water (like a stream) deposited the particles. What general observation can be made about the size of the particles that are deposited first by stream water? Circle one. (The largest are deposited first/the medium sized particles are deposited first/the smallest particles are deposited first.)
5. What general observation can be made about the size of the particles that will be deposited last by running or flowing water? Circle one. (The largest are deposited last/the medium sized particles are deposited last/the smallest particles are deposited last.)

Activity B

1. Why is it important for geologists and archeologists to classify different sediment particle sizes?

   By sorting bits and pieces of rock, geologists and archeologists are making better observations, and can make better inferences about deposits and their environments. Particle sizes indicate specific information about the formation of a landscape.

2. List samples A–E in the order you would expect them to settle?

   D, A, B, C, E

References

Flinn Scientific would like to thank Heather McArdle, Mahopac High School, Mahopac, NY, for this activity.

Introduction

Is it a “bit” of something, or a “piece" of something? Usually, such terms indicate a part of something that is larger in size. Terms like a “bit” or a “piece" indicate relative size, but not measurements. Just how big is a “bit”? Can it be measured? Is there a range of acceptable sizes?

Concepts

• Measurement
• Classification of particle sizes
• Metric conversions
• Particle sizes and deposition

Background

Helpful Definitions

• Deposition—The placement or accumulation of particles or sediments.
• Suspended—Materials carried by weak currents in water; will not sink unless water remains still.

Running water has the power to make dramatic changes in the appearance of the Earth’s surface. Over vast periods of time, running water may change entire landscapes. Dramatic change can be made by floodwaters over short periods of time. The stream bed may change location, change patterns on the land and will also be able to carry debris or particles. Geologists attempt to study past landscapes by understanding where stream beds used to be, how fast the water flowed and how it changed the landscape. They do this by examining the remains of these ancient events—the deposits of these streams and rivers. Particle sizes, where the different particles are found and how the deposits are organized can tell a geologist much about a landscape’s history. In this activity, particle sizes will be identified and classified by measurement.

Materials

Procedure

Activity A

1. Fill a 2-liter soda bottle half-full with three sediments of various size.
2. Fill the remainder of the bottle with tap water.
3. Securely fasten the cap, and shake, swirl and invert the bottle vigorously for 30 seconds.
4. Quickly set the bottle down on the table and observe the appearance of the mixture and the settling/distribution of the particles.
5. Repeat the process one more time. Answer the Activity A Post-Lab Questions.

Activity B

1. Obtain containers of each sediment particles (A–F) for the group.
2. Allow one group member to randomly choose 10 size A particles. Place them in a tray or weighing dish.
3. Measure the longest dimension (in mm) of each of the 10 particles in the tray.
4. Record the measurements in the appropriate column on the worksheet.
5. Average the 10 measurements and record the result on the worksheet.
6. Using the average size, and Table 1, determine the particle classification name.
7. Repeat steps 2–6 for particle sizes B–F.

Student Worksheet PDF

12645_Student1.pdf