Sediment Classification
Summary
Students explore sediment grain size and
practice classifying sediments according
to the Udden-Wentworth scale or a scale
of their own choice.
Learning Objectives
Students will be able to:
• Describe sand, pebbles and boulders
by size.
• Use an established sediment size
scale to classify sediment samples.
National Science Education Content
Standards
•
well as measuring with a microscope.
Sediment comparators are available
from Ward’s Natural Science catalog:
http://wardsci.com/.
• Students should be aware that sand,
silt, clay and gravel are geologic terms
describing specific ranges of grain
sizes, independent of the composition
of those grains.
• Many variations of the UddenWentworth scale can be found online.
Some websites include:
http://www-odp.tamu.edu/
publications/197_IR/chap_02/c2_
f6.htm
http://www.glossary.oilfield.slb.
com/Display.cfm?Term=UddenWentworth%20scale
Standard A: Science as Inquiry
• Standard D: Earth and Space Science:
Structure of the earth system
Ocean Literacy Essential Principles
• Earth has one big ocean with many
features.
TM
Teaching for Science • Learning for Life | www.deepearthacademy.org
• The ocean and life in the ocean shape
the features of Earth.
• The ocean is a major influence on
weather and climate.
• Ward’s (http://wardsci.com) offers
a set of sediment samples. If you
cannot obtain sediment samples,
scaled pictures can be used. A couple
places to start:
http://www.microscope-microscope.
org/applications/sand/microscopicsand.htm
Time: One class period
http://www.sandcollectors.org
Materials
• One possible variation of this lab is to
avoid sharing the Udden-Wentworth
scale with students. Instead, have
students develop their own scale
independently.
Target Age: Grades 9-12
• A variety of sediment samples
• Student pages (included)
• Metric rulers
• Udden-Wentworth scale
• Microscopes
Background
Sediments can be classified by grain
size:
• Students should be familiar with
measuring using a metric ruler as
Sediments can also be classified by
their source:
• Students should have had exposure
to mineralogy and oceanography. That
is, they should be familiar with black
smokers and manganese nodules, etc.
• Again, if samples are not available,
pictures can be found on the internet.
A few suggestions:
Sediment Classification
http://www.cartage.org.lb/en/themes/Sciences/
EarthScience/Oceanography/OceanSediments/
Manganesenodules/Manganesenodules.htm
What to do
1. Tell students that today they will be classifying
sediments. This kind of information can be
very useful for scientists because the type of
sediment tells them a lot about the history of
the sediment, including where it came from
(provenance), how it got there (weathering and
erosion), and the environment of deposition.
(See Climate and Sediment activity to explore
this topic further.)
2. Hand out the sediment samples and the
student pages. Give students—either alone or
in groups—ample time to explore and classify
their samples by grain size.
Manganese nodules and a nodule cross
section.
http://pubs.usgs.gov/of/2000/of00-006/htm/
nodule.htm
http://www.amnh.org/nationalcenter/
expeditions/blacksmokers/
http://www.wnet.org/savageearth/hellscrust/
html/sidebar2.html.
3. Gather the class to discuss their results. Did
every person/group come up with the same
answers? Why or why not?
4. Have the students work together to classify
sediments by their sources. As a class,
develop definitions of lithogenic (derived from
existing rock), biogenic (derived from living
organisms), hydrogenic (precipitated from
water), cosmogenic (extra-terrestrial in origin)
and volcanogenic (derived from volcanoes).
5. Hand out samples for each group to look at and
classify.
6. As a class, compare results for the categories
for their samples.
Submitted by
During ODP Leg 210, Anna Engstrom (Stuctural Geologist;
Sweden) and Rick Hiscott (Sedimentologist; Canada) describe a
sediment core.
TM
Teaching for Science • Learning for Life | www.oceanleadership.org
Dr. Beth Christensen, Adelphi University and
Catherine Wiltsey, Adelphi University
2
Sediment Classification
Student Page
Background
Scientists describe sediments in many ways. The
most common include the size of the particle and
the source or parent material for the sediment.
Sediments come in a variety of shapes and sizes.
A system or standard is needed to organize and
classify sediment based upon grain size. The
Udden-Wentworth Scale has long been used as
this standard.
For each sample:
Instructions
Remember to keep samples separated.
Before you begin:
Extension
1. Describe sand. Explain the difference between
the geological term “sand” and the general use
of the term.
Look at your samples labeled sand. Do you think
that “sand” is specific enough to cover the samples
you have? Explain your answer. If not, how would
you change the classification?
1. Describe the sample. Be sure to include its
composition, size, and shape.
2. Measure the diameter of the sample as best
you can.
3. Classify the sample by size using the UddenWentworth Scale.
3. What about boulders? Compare boulders to
sand and pebbles.
TM
Teaching for Science • Learning for Life | www.oceanleadership.org
2. What is a pebble? Compare your definitions to
those of others and then look at the Wentworth
Scale. How are pebbles similar to sand? How
are they different?
Sediment from the Savannah Scarp. Image from Project Oceanica
at the College of Charleston (http://oceanica.cofc.edu)
3