Activity: Build a Model Submarine
(Activity courtesy of the National Museum of the U.S. Navy).
Grade Level: 5-8
Time Required: One class period
Group Size: 3-4 students.
OBJECTIVE:
Students learn the basic principle of buoyancy and how submarines use it to dive and ascend in water.
MATERIALS:
- a large tub of water
For each student or small group
- Build a Submarine activity sheet
- empty 16 or 20 oz. plastic soda bottles with a hole pre-drilled into the cap. The hole should be large enough to enable a flexible straw to pass through.
- three wide rubber bands
- 24 pennies
- aluminum foil
- adhesive tape
- flexible straw
Background and Introduction:
This activity is part of the U.S. Navy curriculum packet “DIVE! DIVE! An Introduction to the History and Technology of Submarines.” [Click HERE for html version.]
Before students engage in this activity to explore the principles of buoyancy and its operation in submarines, teacher may wish to have the class read about the history and technology of submarines, as explored in the Dive! Dive! Curriculum:
Teachers may also wish to consult our related submarine lesson plan on ballasts (grades 7-12), which contains standards and more extensive background material.
PROCEDURE:
Depending on the size of the group, teachers can choose to have the entire class work together, to have each student work individually, or to divide students into groups of 3-4. It may be helpful to draw the model on the board, or to project the image below.
Directions to Students: 
1. Carefully cut three small holes on the bottom of your soda bottle.
2. Stack the pennies into three piles containing 4, 8, and 12 pennies.
3. Next, carefully wrap the stacks of pennies with foil.
4. Place a rubber band around the plastic bottle and slide it next to the closest hole. Position the other rubber bands next to the two remaining holes.
5. Place the four-penny stack under the rubber band closest to the bottle’s top.
6. Place the eight-penny stack under the middle rubber band, next to the middle hole.
7. Place the 12-penny stack under the last rubber band (NOTE: The weights should be next to the holes NOT over them.)
8. Push the shorter end of the straw (about 1 inch) through the hole in the bottle’s cap. Reattach the bottle cap to the bottle. Keep the flex section outside and bent upwards. Tape straw securely into place in bottle cap.
Have students take turns lowering their “submarine” into the tub of water, while the others gather around observe and take notes. Caution them to avoid letting long end of straw take in water.
When it stops sinking, have one of the students blow into the straw. Everyone should observe the action of the sub and record their observations. Give each group a turn with the activity, encouraging observation and discussion. Does each sub perform in the same way? If not, what makes the difference?
Assessment:
Written or Oral Evaluation
You have observed the basic properties that make submersibles dive and surface.
1. What makes the model submarine sink?
2. What makes it surface?
3. What key elements in the design of this model submarine contribute to its performance? What changes would occur if you altered its design?
3. What is your model missing that U.S. Navy submarines have in order to navigate underwater?
ACTIVITY EXTENSIONS
This activity is part of the U.S. Navy curriculum packet “DIVE! DIVE! An Introduction to the History and Technology of Submarines.” The packet, which consists of background information on the history and development of submarines and a list of cross-curricular activities, can be obtained from the Museum Education Department at (202) 433-6826.
Additional Dive! Dive! materials available online:
Introductory material:
Lesson Plans and Activities:
updated 4/13/2018
Filed under: Class Activities, Grades 6-8, Grades 9-12, Grades K-5, K-12 Outreach Programs, Lesson Plans
Tags: buoyancy, Class Activities, Engineering Design Process, Nautical Engineering, Ocean, Ocean science, submarine, U.S. Navy
