Lesson Title: Creating the Ideal Cargo Boat
Discipline Focus: physical science, mathematics
Grade level: Middle School
Length of lesson: 30 - 45 minutes
Content Standard(s):
Benchmarks and NSES recommend all students develop an understanding of the properties of
objects and materials.
Understanding (s)/goals
Students will understand:
1) the relationships between mass and
volume for objects (boats) that float
2) the concept of buoyancy
Essential Question(s):
1) Why can boats be built of materials that are
heavier than water?
2) What must be done with heavy materials in
order to make them float?
3) What boat design(s) can hold the most
cargo?
Student objectives (outcomes):
Students will be able to:
1) Describe the relationship between mass and volume for boats that float
2) Identify variables affecting a boat’s ability to hold a maximum cargo.
Stage 2 – Assessment Evidence
Performance Task(s):
Other Evidence:
After going through the exercise, students
1) Level of engagement and participation of
will be able to:
students in activities and discussion.
- create a “boat” from materials that have a
2) Demonstration of correct concepts in follow-up
density greater than water;
discussion.
- create a boat with a design that holds a
maximum level of cargo
Stage 3 – Learning Plan
Learning Activities:
Materials
Modeling clay (@ 29-30 gram piece of clay per team)
Triple beam balance or scale
Pans/tubs for testing boats
Paper towels!
Sponges
Bucket for carrying water
Weights or pennies for boat cargo
Background:
 Archimedes was a Greek mathematician who in about 250 BC discovered relationships
between mass and volume that led to an understanding of density and buoyancy. An
object floats when it displaces a volume of fluid (water) whose weight is greater than or
equal to its own weight. An object will float in a fluid (water) if the density of the object is
less than the density of the fluid.
 The density of water is 1 gram per cubic centimeter.
Procedures (teacher/fellow pairs work as teams):
1. Your team’s problem: To design and build a boat out of a specified amount of clay that
will float carrying the heaviest possible cargo.
2. Begin by discussing what you know as a team that might help design the ideal cargo boat.
Record your key ideas in the journal (A).
3. Based on your team’s knowledge, design a boat that you will build. Sketch the design in
the journal (B).
4. Build your boat and make sure its mass is 29-30 grams. Record the mass of your boat in
the journal (C).
5. You will have a maximum of 12 minutes to discuss, plan, & build your boat. Then 2-3
teams per “lake” will take turns testing to see how heavy a cargo their boat can hold
before it sinks. You only get one attempt to put cargo in your boat until it sinks.
6. Each team should note their maximum cargo load in their journal (D).
7. After testing your boat discuss possible redesign options for your boat. Either complete a
redesign/rebuild of the boat, or prepare to test the same boat a second time.
8. Provide a sketch and notes on your rationale for either redesigning and rebuilding your
boat or simply retesting your initial design (E).
9. When your table is ready, complete a second test and record the results in the journal (F).
10. Additional redesign tests can be done if time permits.
11. When your team has completed these efforts, answer questions G-I in the journal.
12. If your team has time, discuss how you would answer the activity extensions.
Activity Extensions:
 Describe how you could determine the volume of your boat.
 Describe how you might calculate the largest potential cargo your boat could hold given
the materials you will be able to use to build your boat. (For calculation purposes, assume
the density of water is 1 gram per cubic centimeter.)
Online Resources:
http://www.eduref.org/Virtual/Lessons/Science/SCI0025.html
http://www.thirteen.org/edonline/nttidb/lessons/jx/buoyjx.html
http://www.thirteen.org/edonline/nttidb/lessons/as/derbyas.html
http://www.sciencenetlinks.com/lessons.cfm?DocID=143
http://www.stoller-eser.com/nie/PDFs/Buoyancy.pdf
http://hyperphysics.phy-astr.gsu.edu/hbase/pbuoy4.html
http://www.visionlearning.com/library/module_viewer.php?c3=1&mid=37&l=
http://tlc.ousd.k12.ca.us/~acody/densitymisc.html