Cranberry Raft Engineering

Standards

• 3-5th grade: SCI.SEP2.3-5, SCI.SEP3.3-5, SCI.ETS3.C.3-5

The Cranberry Raft Engineering Challenge is a great hands-on engineering challenge.  This is an excellent fall STEAM or STEM activity for small groups.   Students will have the opportunity to design their own raft and evaluate their small groups’ individual designs.  Using problem solving skills the group will design, assemble, and test their Cranberry raft with 2 fun challenges. 

The materials needed are:

• Fresh Cranberries (2 cups)

• Toothpicks

• Pencils

• Cardstock

• Scissors

• 10  pennies/ group

• A tote or bowl for water

The first challenge is to construct a raft that floats.  Students will discover basic structural engineering techniques through trial and error.

After completing the first challenge they will try and hold the weight of 10 pennies.  Be sure to add one at a time!  The importance of distribution and structural stability become obvious.

Finally, add some fun competition and see whose design can hold the most pennies!  

After the challenge talk about what design techniques worked well and which ones did not.  Discuss reasons why certain designs did better than others.

As always, talk about different careers where students can use these skills.