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Building Boats




Project Description (5)

Students will design and build their own boats using recyclable/every day items. They will practice math skills by working with a materials budget. The students will observe the concepts of buoyancy and density at work and gain a greater understanding of how this effects boats.

Recommended Grade 5th grade
Sciece Topic Force and Motion

Force and Motion: North Carolina
5.P.1 Understand force, motion and the relationship between them.
5.P.1.4 Predict the effect of a given force or a change in mass on the motion of an object.

Engineering: NGSS
3-5-ETS1-1. Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.
3-5-ETS1-3. Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.


Why do things float? It has to do with their density. Density describes how much mass is packed into an object. Mass is the stuff that everything is made of. Something with more stuff will be more massive. Water is pretty dense and only objects with a greater density than water will sink.

Learning Outcomes

Students should be able to describe what happens to the mass and buoyancy of the boat when the pennies are added.

Students should be able to describe the forces acting on the boat before and after the pennies are added.

Students will have to work within their budget and learn to iterate to produce a cost-effective boat that holds a maximum number of pennies.


-Aluminum foil
-Popsicle sticks
-Scotch tape
-Bucket or bin filled with water
-At least 10 pennies
-Money chart

1. Fill the bin with water
2. Gather supplies
3. Optional: Supply list prices worksheet


1. Introduce the project and then introduce the students to the basics of buoyancy and density. We do a demonstration with items that will float and sink.
2. Show students all the supplies. Let them know the challenge is to build the boat that holds the most pennies.
3. Students are provided with a money chart noting how much each item available will cost.
4. Students should design their boats and calculate the total cost of their boats.
5. Once students settle on a design and budget they should build a prototype.
6. When students are done test the boats and make observations about what worked and what did not.
7. Optional: give students a chance to redesign their boast if they have money still available to them.

1. Reflect on what designs were successful and how it was working with a budget.

Time Estimate: 75 minutes


The 2016-2017 school year will be our first year with 5th grade students. We are excited to try a more in-depth version of this project with our 5th graders.