Sink or Float? Edwin Portillo


Design and build a model boat that will hold as much weight as possible without sinking, using no more than three items from the material box.

Background Information

To complete the project, students must be familiar with:

  • The properties of water
  • Different states of matter
  • Density
  • Buoyancy

Properties of Water




The students will develop the following knowledge and skills in each of the areas below:

  • Mathematics -The student is expected to:
  • Apply measurement concepts involving length (including perimeter), area, capacity/volume, and weight/mass to solve problems.
  • Perform basic conversions within the same measurement system (SI [metric] or customary).
  • Incorporate the problem solving process (i.e., understand the problem, make a plan, carry out the plan, and evaluate the solution for reasonableness) when solving problems.
  • Science – The student is expected to:
  • Apply the property that matter has measurable physical properties and that those properties determine how matter is classified, changed, and used.
  • Classify matter based on physical properties, including mass, magnetism, physical state (solid, liquid, and gas), relative density (sinking and floating), solubility in water, and the ability to conduct or insulate thermal energy or electric energy.
  • English – The student is expected to:
  • Apply prewriting strategies to generate ideas, develop voice, and plan.
  • Write persuasive texts to influence the attitudes or actions of a specific audience on specific issues.
  • Determine, locate, and explore the full range of relevant sources addressing a research question and systematically record the information he or she gathers.
  • Synthesize collected information then organize and present ideas and information according to the purpose of the research and the student’s audience.


A tropical storm has completely flooded the streets in your neighborhood. Unfortunately, you are stuck at school. The only way to get back home is to build a boat to travel the streets covered in water. You and two of your classmates will explain the concepts of buoyancy and density that will lead to designing and creating a model boat that will hold as much weight as possible without sinking using the materials provided. You will be given a box of materials that can be found throughout the school, and you may not use more than three different types of materials from the box to build your boat. Your boat may be any size or shape as long as it meets the given criteria: The ability to safely float while holding at least one classmate (5 small marbles). To complete the project, your boat must be transported to the docking station and be able to float without you touching it. Once the boat is placed in the water, it will be judged on how much weight it can hold before it starts to sink. Lastly, using what you learned about buoyancy and density, you will present your boat design to the class by persuading your classmates to use your boat in order to get home safely.


  • Scissors
  • Tape (duct, Scotch, packing, etc.)
  • Elmer’s glue
  • Tub of water
  • Formula Chart
  • Ruler
  • Computer (PowerPoint®/presentation media, Internet access)
  • Variety of materials found in classroom to build boat (cardboard, foil, clay, tin can, popsicle sticks, etc.)
  • Pencils
  • Notebook paper or student journals
  • Marbles or some sort of object to use as weight measurement
  • Balance beam

Day 1

Start the project by discussing the terms buoyancy and density. Give the students five minutes to brainstorm in their journals what they know about these two terms. Let them share with their friends their answers.



  • Why did the ship sink?
  • How are some ships able to hold more than others do?
  • Why do some objects sink when other objects float?
  • What about objects that are the same size but different masses or different shapes?
  • When you go swimming, do you float or sink?
  • Can you ever have too many people aboard a boat?
  • How do you know? What might happen?
  • What is surface area?
  • Do you think surface area relates to ships and their ability to float or sink?

Day 2

Divide the class in groups and let them brainstorm ideas and methods of how to build a boat that would not sink and let them sketch possible designs. It should include:

  • Dimensions
  • Possible materials (from the box provided by the teacher)
  • How they are going to test the design before they are judged.

Day 3

Students start building their boats using three materials chosen from the box for their final products. They should keep track of any information and research done during the previous day and any changes done to the boat during research. By this day the students should be able to discuss the following: – What they have learned about ships and their ability to sink or float? – What challenges have they encountered and what observations have they made on the different types of materials available? They should be able to explain: What is buoyancy? What are the key factors that affect an object's ability to float?

Day 4

Students test their boats before being judged. Once the boats are judged, students start preparing their presentations Each presentation should include the following: a) what materials were used to build the boat and why, b) how successful was the boat and how many people could it hold, c) what makes the boat the best using the concepts of buoyancy and density, d) the dimensions or shape of the boat and how that contributed to the boat’s success, and e) any other persuasive information the students wish to include (pictures, advertisement videos/posters, etc.).

Day 6

Presentation and selection of the best design.


Evaluation will be done based on the sentry journals, boat models and presentations using the rubrics. Rubric from pages 116 to 118 companion book by Capraro, Whitfield, Etchells, and Capraro (2016).


Project based on:

Capraro, M. M., Whitfield, J. G., Etchells, M. J., & Capraro, R. M. (2016). A companion to interdisciplinary STEM project-based learning: For educators by educators. Rotterdam, The Netherlands: Sense Publisher.

Created By
Edwin Portillo


Created with images by 99pixel - "tub palio race" • Create-Learning Team Building & Leadership - "High School Student Team Development: Gow School, South Wales NY" • Mariamichelle - "people person boys" • rjacklin1975 - "stuworkhard1" • PublicDomainPictures - "children classroom students" • PublicDomainPictures - "ship away boat" • Newtown grafitti - "Paper boat" • Tall Chris - "boat" • Robin Iversen - "Boats" • Psomas Paper Yacht Challenge - "P1030711" • riteshman - "paper boat origami" • John-Morgan - "Paper Boats" • Gabriel GM - "Sailing day" • Gabriel GM - "Sailing day" • StartupStockPhotos - "children win success" • Wm Chamberlain - "Noel Science Fair Winners" • Wm Chamberlain - "Winner" • bortescristian - "UBBOTS - January 2011"

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