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Penny Boat Challenge



1-2 hours
3rd Grade
4th Grade
5th Grade
6th Grade
Key Terms: 
aluminum foil
plastic container
dependent variable
independent variable
upward force
Tubs that hold water

Lesson Overview

Teacher Overview:

Put students into groups of two to four.  Challenge the groups to build a boat out of aluminum foil that will hold the most mass.  Give each group two pieces of 6in x 6in aluminum foil. One of the pieces is to test with and the other piece is for their final product. This is a great way to introduce dependent variables and independent variables.  The dependent variable is the penny(s) and the 6in x 6in aluminum foil. The independent variable is the shape of the boat. Groups will use pennies as their mass to see how many pennies their boat will hold before it sinks.  Before groups put pennies into their boats, have each group predict how many pennies their boat will hold. Each time they redesign their boat, have the group make a new prediction. These predictions can be put into the chart we have included. The group that makes a boat that holds the most pennies (mass) wins. Teachers can give each group their own plastic container filled with water or if you want to test one at a time, the teacher can place one container filled with water on a desk.  We suggest that you have a container for each group to test in. Teachers can incorporate many Standards into this lesson depending on what grade they teach. Teachers can have students measure the perimeter and area of the aluminum foil, you can create a bar graph of all the boats and their mass and find the range, median and mode of the sinking boats.


Student Summary: 

Can the shape of a boat affect the amount of buoyancy it has? Buoyancy is the upward force that keeps things afloat. When you place something in water it will float if the buoyancy is pushing up more than the weight of the object. Cut out a 6x6 inch aluminum foil sheet.  Sketch a design and build a boat to hold as many pennies as possible. The boat must float for five seconds. Count how many pennies your boat has until it sinks. Add one penny at a time until it sinks.


Lesson Phases


We are using aluminum foil, pennies and water to test the buoyancy of the 6 inch by 6 inch boat we are going to make.


Buoyancy is the upward force on an object that keeps it afloat. The boat will sink when the weight is more than the buoyancy.


The independent variable is something we changed in our boat design, the dependent variable is what changed as a result of a new design.

Sink or Float

Some of the boats looked like this. The constants were each group got a 6 inch by 6 inch piece of aluminum foil and we all had a tub of water.

Student Video