This resource is a part of the Engineering & Robotics lesson series.
Building a Simple Submarine
Grade Level: 7th – 12th grade
Length of Lesson: 45 minutes
- Construct a model of a submarine’s ballast system
- Develop an understanding of an active ballast system
- Develop skills to devise a ballast system for a SeaPerch ROV
National Science Standards:
- A: Forces and Motion
- C: Relationship Between Energy and Force
- A: Defining and Delimiting an Engineering Problem
- 24 inches of flexible tubing with a 3/8 inch outside diameter
- 16 oz. plastic soda or water bottle with cap
- Approximately 8 oz. of ballast weight
- Electrical tape
- 3/8 inch drill bit and drill
- 5 gallon bucket filled with water
A submarine controls its ballast by allowing water to fill ballast tanks located around the ship. To make a submarine submerge, vent valves at the top of the ballast tanks open, allowing air to escape and water to fill the tanks through holes in the bottom. To make a submarine surface – the vent valves are shut and high pressure air is released into the tanks forcing the water out through the holes in the bottom.
- Place the bottle in the 5-gallon bucket and make sure your thumb is over the other end of the tubing.
- Now remove your thumb and watch as the bottle fills with water. You should feel air rushing out of the tubing.
- When the bottle has sunk to the bottom, blow into the tubing and watch the bottle come back to the surface.
- Drill a 3/8 inch hole in the bottle cap and the bottom of the bottle.
- Tape the ballast weight to the bottom of the bottle.
- Place the flexible tubing in the hole in the cap and insert it about 1 inch.
- Tape the tubing in place.
- Screw the cap onto the top of the bottle.
- Have students analyze the experiment and answer the following questions:
- What did you observe?
- Why do you have to place your thumb over the end of the plastic tubing to keep the bottle afloat?
- How would you be able to put an active ballast system on your ROV?
- What would be the advantages and disadvantages to an active ballast system?
How Does a Submarine Sink and Rise? Soda Bottle Diver / Cartesian Diver Physics Experiment (NPS Physics – YouTube)
Exploring Air & Air Pressure (Fun Science Demos – YouTube)
Submarine Ballast Tanks (9spiderlegs – YouTube)