Science Lesson Plans
Posted Mar 01, 2016 by Elmers
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    Build a Boat Challenge

    Students will use scientific principles of buoyancy, water displacement, and engineering to design a boat.
    • 3 - 8
    • 4 hr
    • Science

    How do I get my class and myself ready? This lesson plan should give you everything you need to be prepared for the material.

    Lesson Plan Objective(s)

    Students will understand the concepts of buoyancy and water displacement to design a watercraft that will support a given amount of weight.  Students will incorporate the scientific principles of force and motion with engineering design and mathematics to participate in a boat-building challenge.

    Background Details

    The Framework for K-12 Science recommends that children in the elementary grades have opportunities to engage in design challenges that require an application of scientific principles. Set the stage for learning using literature and a demonstration of a discrepant event to review the scientific principles involved and engage students in the inquiry process. They will then have the background information they need to design a boat that will support a given amount of weight with specific materials. These activities culminate in a boat design challenge so that students can demonstrate and share their learning.

    Recommended Reading & References

    Captain Kidd’s Crew Experiments with Sinking and Floating by Mark Weakland

    What Floats? What Sinks? A look at Density by J. Boothroyd

    Mr. Archimedes' Bath by Pamela Allen

    Floating and Sinking by K. Bryant-Mole

    Floating and Sinking by Ellen S. Niz

    Materials Needed

    • Build a Boat PDF (download handout)
    • Clear aquarium or tub filled with water
    • Aluminum foil
    • Butcher paper
    • Sharpie® Markers

    Small group boat building kits:

    Required Knowledge/Vocabulary

    sink, float, buoyancy, gravity, force, water displacement


    Next Generation Science Standards

    MS-ETS1 Engineering Design
    3-5-ETS1 Engineering Design

    Common Core

    Reading: Informational Text, Literature
    Writing: Text types and purposes

    How do I present the material? Here is the recommended approach, content and timing for presenting the materials.

    Lesson Instructions

    Begin with a simple demonstration. Show the students two sheets of aluminum foil that are exactly the same size. Ask them if they think the aluminum foil will sink or float if you place it in the water. Give students an opportunity to support their guesses. 

    Place one piece of aluminum foil on the top of the water. Ask them if they can think of any way to change the second sheet of aluminum foil so that it sinks rather than floats. 

    Crumple the second piece of aluminum foil into a ball and place it in the water. Ask students why they think the ball of foil sank when the sheet of paper floats. 

    Explain the concept of water displacement and discuss. 

    Next, read the book, What Floats? What Sinks? by J. Boothroyd aloud to the students. Take time to reinforce the scientific principles of buoyance, gravity, water displacement and force. Stop periodically to discuss the illustrations and content. It is a great idea to make additional literature resources available in the room for students to explore on their own.

    Discussion Questions

    1. Why do you think this small ball of aluminum foil sank and the sheet of aluminum foil floats?
    2. Why do you think large boats can float when a penny will sink? 
    3. What do you think impacts whether something will sink or float? 

    Activities (group or individual)

    Explain to the students that they will participate in a boat-building challenge. Provide each with a copy of the Boat Design Challenge handout (download PDF) and group them into teams of 3-4 for the challenge. Distribute the Boat Design Challenge kit to each group and allow enough time for them to brainstorm, design, build, and test their models. 

    When every group has had time to test and improve their models, host a Classroom Boat Design Competition. Each group should be prepared to explain the rationale for their boat design before testing the weight it will support. Encourage students to record the weight and cost for each model on the data collection form so that all students will be involved in identifying the winner.

    Use a Sharpie marker to create a data collection form on a large piece of butcher paper as the students record the data on their individual sheets.  Invite students to add the data to the butcher paper form as each group shares their boat with the class.

    Did my students achieve the lesson objective?

    Discussion Questions

    1. How cost effective is your boat to construct?
    2. Can you make improvements to your boat so that it will support more weight?
    3. What is the most challenging part of the design process?
    4. Which is more important - function or appearance? 

    Activities (group or individual)

    Extension activity for grades 6-8: Explore the history of the Titanic and connect the principles of buoyancy, gravity, structural design, and force. Ask students to explain why this great ship sank using the key vocabulary words. Visit to access a virtual field trip, On Board the Titanic. Students select one of five characters to be on board the Titanic. After spending a few “virtual days” on board the ship, they will discover whether they survive. 

    Helpful Tips and Tricks

    This is a great activity to use to engage students in scientific inquiry, investigation, and engineering design. Be sure to allow enough time for students to test their designs and make improvements. This is an important part of the process. 

    Download and print the parent letter (PDF in the Resources section) for students to take home and encourage further learning. 

    Lesson Plan Downloads


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