CLASSIFYING SHELLS
Lesson Plan
TARGET AUDIENCE
Kindergarten-2nd grade
STANDARDS
VA grades K-2: Scientific investigation, reasoning and logic; Matter; and Earth patterns,
cycles and change.
MD grades K-2: Constructing knowledge, Applying evidence and reasoning,
communicating scientific information.
DC grades K-2: Scientific inquiry, Life science, and Physical science.
* See page 3 for an in-depth list of standards of learning covered in this program.
OVERARCHING GOAL
To observe, describe, compare and contrast, and sort a variety of shells as a means of
developing classification strategies.
STUDENT OBJECTIVES
1. Students will touch and make observations about a variety of shells.
2. Students will compare and contrast their shells’ physical characteristics.
STUDENT OUTCOMES
1. Students will describe the physical characteristics of a variety of shells.
2. Students will sort their shells into groups and create a shell “exhibit” based on
classification strategies.
MATERIALS, RESOURCES, TIME, AND SPACE
Materials/resources: variety of shells, index cards, trays, blank paper.
Time: 45 minutes
Space: Discovery Room.
= denotes special needs lesson accommodations.
PROCEDURE
Discussion/brainstorming on collecting and sorting with Docent (5 min.):
Welcome school group and begin the brainstorming session by asking the following
questions: What do you collect? What do you do with your collection (how do you
display it)? Explain that shells are one of the things scientists in the Museum collect and
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today we are going to talk about collections of shells and how to classify them. Explain
that today, you are going to be just like a museum scientist as you observe and study
shells. Explain Activity #1.
Activity #1 (10 min.)
Divide the students into groups of 4-5. Give each group a selection of shells. Ask them
to describe the way the shells look and feel. A chaperone should act as group recorder.
Activity #1 Discussion with Docent (5 min.)
Docent asks the students to share the different words they used to describe their shells
and makes a list of the vocabulary.
Draw pictures to help illustrate vocabulary and make sure each term is described –
feel free to ask the students “what do you mean by spiky, do you mean sharp points?”
Docent points out themes within the suggested words, such as color, shape, size,
texture, and pattern.
Highlight or record theme words in certain colors and use the color scheme in the
labels.
Explain Activity #2. You are scientists designing an exhibit of shells to display in the
Museum. How are you going to arrange and organize your shells? Refer students to
the words and categories from Activity #1 and explain that when they are finished, they
will share their “exhibits” with each other.
Activity #2 (10 min.):
Students return to their groups. Each group works collectively to sort the shells in
several ways, and decides upon a way to group the shells for their “exhibit.” Docent
gives each group an index card indicating their method of sorting – color, size, shape,
texture, or pattern. Students display their shells in groupings in a tray.
The method that students choose could be written in the color used to label the
descriptive words.
Sharing (10 min.)
All trays are brought to the front of the room as the students reconvene on the steps.
Each group presents their “exhibit” and explains how they sorted the shells and why.
Closure by Docent (5 min):
Docent notes that students sorted their shells in different ways and then explain that
now they are going to show the students another example of how to sort the shells:
univalves and bivalves. Explain the difference between these two types of
shells/animals, giving examples. Explain that just like the students did in their last
activity, scientists that work at the Natural History Museum also sort shells by the way
they look. One of the ways that scientists here at this Museum sort shells is into these
two groups. Note that there is more than one way to sort the shells – there is not one
“right” way. Thank the students and their teachers for coming. Encourage them to look
for more shells in the Museum and to practice describing and comparing them.
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STANDARDS
VA grades K-1:
 K.1: a) Basic properties of objects observed.
b) Observations made from multiple perspectives.
c) Verbal description of objects are made.
e) Objects grouped by physical attributes.
g) Questions are developed from observations.
j) Unusual and unexpected results in activity recognized.
 K.2: a) Use senses to gather information.
b) Sensory descriptors are used (rough/smooth, etc).
 K.4: Students learn that physical properties of an object can be described.
These properties include:
a) Colors;
b) Shapes and forms;
c) Textures and feel;
d) Relative size and weight.
 K.8: b) Students will investigate and understand simple patterns in the shapes
and forms of common natural objects.
 1.1: a) Differences in physical properties observed.
c) Objects are arranged according to attributes and/or properties.
d) Observations are communicated orally.
f) Predictions are made based on patterns of observations.
h) Inferences are made, conclusions are drawn.
 2.1: Scientific investigation, reasoning and logic.
MD grades K-2:
 Standard 1.A.1.a) Describe what can be learned about things by observing.
b) Seek information through observations, exploration and
investigation.
 Standard 1.B.1.a) Provide reasons for accepting ideas.
b) Develop reasonable explanations for observations made,
share ideas and listen to other’s ideas.
 Standard 1.C.1.a) Describe things as accurate as possible and compare
observations with others.
b) Describe and compare things in terms of texture, shape,
texture, size, color.
d) Work in a team, share findings with others, recognize that
all should reach their own conclusions about findings.
DC grades K-2:
 K.SI.3. Use senses to gather information.
 K.PS.3.2. Investigate and compare physical properties of objects.
 1.1.1. Observe and sort objects as a way of categorizing some properties.
 1.1.2. Make observations to seek answers to questions.
 1.1.7. Describe and compare objects by shape, texture, size and color.
 2.1.1. Describe objects and compare observations with others.
 2.1.3. Demonstrate ability to work with a team.
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CLASSIFYING SHELLS
Background Information for the Teacher
Scientific Method
The scientific method is the way scientists learn and study the world around them. The
basis of the scientific method is asking questions and then trying to learn the answers.
Scientists begin by making observations about the world around them. These
observations usually lead scientists to ask questions about what they see and know.
After coming up with a question, scientists use what they already know to guess
possible answers to their question. Next, they test one scientific guess, or hypothesis.
Scientists can then determine an answer to their question based on their evidence.
Hypotheses that scientists come up with must be able to be tested again, so that other
scientists can repeat the test to confirm the outcome. Scientists can learn things from
what other scientists have already questioned, tested, and answered. In this way, each
scientist can build on what has been learned before by other scientists – or possibly
begin with something that has never been questioned or tested!
Image courtesy of http://www.biology4kids.com
Classification
Scientists name and group all the living things on Earth in an effort to make it easier for
people throughout the world to use the same name for organisms. Over the years there
have been many different ways of classifying, or grouping, things. Scientists are
constantly revising classifications, sometimes every day! The currently accepted
system of naming and classifying organisms is called binomial nomenclature, and was
invented by Carl Linnaeus (1707-1778). According to this system, all organisms belong
to a single Kingdom, Phylum, Class, Order, Family, Genus, and Species. Organisms
are named by their Genus and Species, written: Genus species.
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There are many characteristics of organisms that allow them to be identified and
classified with other similar organisms. These characteristics may include outward
appearance, internal morphology, genetic relatedness, and sometimes behavior and
ecology.
Shells and Mollusks
Shells are made by animals called mollusks, and are part of their bodies. Mollusks
have soft and fleshy bodies. In order to protect their soft bodies, they encase
themselves in hard, external shells made of lime (calcium carbonate). They secrete this
substance from a part of their bodies called the mantle. There are 110,000 species of
living mollusks, and many, though not all, of these species have an external shell.
Shells can often be used to help identify mollusks by species. Mollusk shells are very
hard and act as protection. Many mollusks can seal their shells closed so that their soft
bodies are protected within. Shells may also help prevent mollusks that live on land
from drying out. The colors and patterns of shells may act as camouflage or warning.
Mollusks live in many different environments, and can be sessile or may move in one of
several ways. Some species of mollusks creep about on land, some live on top of or
burrow into the ground sediments of fresh or salt water, and others swim freely about
the ocean. Mollusks range in size from minute snails and clams, which are less than a
centimeter in size, to the giant squid, which can reach 18 meters (60 feet) in length.
Univalves and Bivalves
The class of mollusks called Gastropoda includes snails and slugs. Gastropods may
live on land, in fresh water, or in salt water. There are 90,000 living species of
gastropods, making up 80% of living mollusk species. Not all gastropods have shells,
but those that do have shells with only one part. Any animal with a shell that has only
one part is called a univalve.
The class of mollusks called Bivalvia includes clams, mussels, oysters, and scallops.
Bivalves live only in fresh or salt water; there are no terrestrial bivalves. There are
15,000 species of bivalves, making up 13% of living mollusk species. All bivalves have
shells that are made up of two parts, called valves. Bivalve shells are hinged and are
held together by large bands of muscle. Bivalves’ bodies are soft and quite sensitive to
irritation, so they secrete a mucous material called mother-of-pearl that hardens and
lines the inside of the shell and helps protect their sensitive bodies.
Univalve shell
Image courtesy of http://www.manandmollusc.net
Bivalve shell
Image courtesy of http://users.actrix.co.nz
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Glossary
binomial nomenclature Noun. The scientific system of naming an organism using two terms, the first
being the genus and the second the species. The terms are usually Greek or Latin and are written in
italics, such as: Genus species.
bivalve Noun. A class of mollusks with two shells.
classify Verb. To arrange, organize, or order by classes.
classification Noun. One of the groups, or classes, into which organisms may be or have been
classified.
ecology Noun. The science of the relationships between organisms and their environments.
evidence Noun. Something that supports, proves, or indicates a theory to be valid.
experiment Noun. A trial for the purpose of discovering something unknown.
gastropod Noun. Any mollusk of the class Gastropoda, including the snails, whelks, and slugs, and
many more similar animals.
hypothesis (plural: hypotheses) Noun. A proposition given as an explanation for the occurrence of
some specific occurrence.
lime Noun. A white or grayish-white, odorless, lumpy, very slightly water-soluble solid, CaCO3 (calcium
carbonate), that makes up the outside shells of mollusks.
mantle Noun. A part of a mollusk’s body onto which they secrete the lime used to make their shells.
mollusk Noun. Any invertebrate typically having a shell of one, two, or more pieces that wholly or partly
enclose the soft, unsegmented body.
morphology Noun. The form and structure of an organism.
mucous Noun. A slimy mixture of water, electrolytes, skin cells, and other substances that is secreted by
glands in mollusks that serves primarily to protect and lubricate the animal.
observation Noun. An act of noticing, perceiving, regarding attentively, or watching.
organism Noun. A form of life.
scientific method Noun. A method of research in which a problem is identified, relevant data is
gathered, a hypothesis is formulated from this data, and the hypothesis is tested.
sediment Noun. A mineral or organic matter deposited by water, air, or ice that is often found at the
bottom of liquid, such as on the bottom of an ocean or a river.
sessile Adjective. Permanently attached, or not freely moving.
shell Noun. The hard outer covering of a mollusk.
terrestrial Adjective. Growing or living on land; not aquatic.
univalve Adjective. Composed of a single shell.
valve Noun. One of the two or more separable, hinged pieces making up certain shells.
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Resources
Suggested Web Sites:
Smithsonian National Museum of Natural History
Marine Science http://www.si.edu/marinescience/
Smithsonian National Museum of Natural History—Marine Science Station at Fort
Pierce
Species Inventory http://www.sms.si.edu/irlspec/index.htm
Conchologists of America
What is a mollusk? http://www.conchologistsofamerica.org/conchology/
Conchologists of America
What is a shell? http://www.conchologistsofamerica.org/theshells/
Suggested Books:
Arthur, Alex. (2000). Eyewitness: Shells. New York, NY: DK Children.
Dance, S. (2002). Shells (Smithsonian Handbooks). New York, NY: DK Adult.
Gilpin, Daniel. (2006). Snails, Shellfish, and other Mollusks. New York, NY: Compass
Point Books.
Parker, Steve. (2004). Eyewitness: Seashore. New York, NY: DK Children.
Silver, Donald M. (1993). One Small Square Seashore. New York, NY: W. H.
Freeman and Company.
References:
Bourquin, Avril. (N.D.). A Beginner’s Guide to the Mollusks. 20 Feb 2007.
<http://www.manandmollusc.net/kid_zone.html>
Dance, S. (2002). Shells (Smithsonian Handbooks). New York, NY: DK Adult.
Gilpin, Daniel. (2006). Snails, Shellfish, and other Mollusks. New York, NY: Compass
Point Books.
Holley, Walter Dennis. (1994). Animals Alive!: An Ecological Guide to Animal Activities.
New York, NY: Roberts Rinehart Publishers.
Rader. (N.D.). Reasoning in Science. 14 Feb 2007.
<http://www.biology4kids.com/files/studies_scimethod.html>
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CLASSIFYING SHELLS
Ancient Seas Exhibit Activity Sheet
Name ________________________________________________________________
Locate a collection of shells within the Ancient Seas Exhibit. Draw four shells that you
see in the boxes below.
If any of the shells you drew are alike, circle them. How are they alike?
______________________________________________________________________
______________________________________________________________________
How are the shells in the exhibit sorted?
______________________________________________________________________
______________________________________________________________________
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