The Ocean Floor and its Features
Summary
Students will use models to gain an understanding of the ocean floor and its features in
comparison to the continents. They will also explore the different kinds of life that live in
the ocean, on the ocean floor and IN the ocean crust.
Learning Objectives
Students will be able to:
 Identify features on the ocean floor
 State that the features are similar to features on land
 State that there are microbes living in the sediment and the oceanic crust.
Materials
Colored pencils or crayons
Bathymetric map
Computer with internet connection
Powerpoint presentation + projector
Copies of student worksheet and diagram
Optional: PlayDoh or modeling clay
Background
This lesson focuses on the physical features of the ocean floor as well as emphasizing
how vast the living space is within the ocean. Three web sites have been outlined and
provided below for the background information for the activities.
The ocean floor is not flat like it appears in some of the underwater footage. There are
large areas of the ocean that appear flat because they are covered by sediment but the
reality is that there are mountain ranges (mid-ocean ridges), stand-alone mountains
(seamounts), volcanos (hydrothermal vents) and really deep valleys (trenches) that make
for a very dynamic seafloor.
Pretest
Give the students a blank “student worksheet” and have them label the diagram using the
following words:
Oceanic crust
Continental crust
Hydrothermal vent
Mid Ocean Ridge
Sediment
Seamount
Land
Procedure
 Prepare the math problems on the diagram. This is a very flexible lesson - adjust the
difficulty to the level of your students. Make sure that all the sediment areas are
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the same number (refer to the key for this). Similarly, make sure both oceanic
crust areas are the same number.
o Addition (1 or more digits, decimals)
o Subtraction (1 or more digits, decimals)
o Multiplication (1 or more digits)
o Division (1 or more digits)
o Fractions
o Algebra
Pass out the student worksheet and diagram as well as colored pencils or crayons.
The students should do the math problems on the diagram first.
Then the students should go through the worksheet and color the diagram according
to the directions on the worksheet.
Talk about the model – use the images in the PowerPoint presentation and/or a
bathymetric map to help show the features.
o What does the blue represent?
o Where is the land?
o Where is the top of the ocean?
o Do the features on the ocean floor look anything like what you would find
on land?
 Hydrothermal vent = similar to volcano like Mt. St. Helens
 Seamount = hill or mountain
 Mid ocean ridge = volcano like Hawaii
 Sediment = any mud or sand you find on land
o Discuss that the ocean floor is not flat – that it has mountains and valleys
just like on land.
Hand out the vocabulary words to the students
o What words do you recognize?
Have the students cut and paste the words on their diagram
As you label each feature, ask students to figure out which definition matches that
vocabulary word (this enables them to deduce from the picture what the
vocabulary words mean)
Optional: Put the students in groups and have each group use clay or PlayDoh to
make a model of the ocean floor including a hydrothermal vent (should look like a
volcano), a seamount (should look like a small hill or mountain) and a trench
(can make by digging a linear ditch-like feature with a stick).
Discuss the features and how the ocean floor is not flat.
Ask the students to brain storm animals and organisms that live in the ocean.
Ask the students to brain storm those that live on the ocean floor.
Ask the students if they think there is life below the ocean floor in the sediments
and the oceanic crust. (They should remember from their exercise that microbes
live in the sediments and crust.)
Show the Powerpoint images of microbes and discuss that millions of them can fit
inside a dot on the chalkboard/whiteboard. They live in the sediment and in
between the rocks in the oceanic crust. Have the students make dots on the
sediment and oceanic crust on their diagram to represent the microbes if they
haven’t done so already.
 Ask the students what they think the worms and shrimp feed on? (Answer: the
microbes that live on hydrothermal vents.)
o Show them a video of mussels that live at hydrothermal vents:
http://oceanexplorer.noaa.gov/explorations/04fire/logs/april11/media/eifuk
u_mussels_video.html
o Show them a video of shrimp that live at hydrothermal vents:
http://oceanexplorer.noaa.gov/explorations/04fire/logs/april02/media/rota_
shrimp_video.html
o Show them a video of the tubeworms living on hydrothermal vents. You
can find a link to the video on this website:
http://www.ceoe.udel.edu/deepsea/level-2/creature/tube.html
 Ask the students what animals they think live in the trenches.
o Explore this page for pictures of animals found in the Mariana Trench:
http://deepseachallenge.com/the-science/biology/
Post-Test
Have students draw the ocean floor again and label the features using the same word
bank as the pre-test.