• lenny-learning-logoLenny Learning
  • Home
    Home
    • Lessons
    Lessons
  • Curriculum
    Curriculum
  • Surveys
    Surveys
  • Videos
    Videos
  • Support
    Support
  • Log In
lenny

Sink or Swim Boat Builders

user image

Morgan Manley

Tier 1
For Schools

Lesson Plan

Sink or Swim Boat Builders

Students will predict and test whether various objects sink or float, then apply their findings to engineer a simple foil boat that holds as many coins as possible.

This lesson engages 1st graders in hands-on exploration of buoyancy, fosters scientific inquiry and recording skills, and introduces basic engineering design and problem-solving in a fun challenge.

Audience

1st Grade

Time

30 minutes

Approach

Hands-on inquiry and design challenge

Materials

  • Aluminum Foil Sheets, - Water Tray or Tub, - Variety of Small Objects (Plastic Block, Rock, Sponge), - Pennies or Coins, - Paper Towels, - Predict & Test Recording Sheet, and - Boat Design Worksheet

Prep

Prepare Materials

10 minutes

  • Tear or cut aluminum foil into approximately 20×20 cm squares, one per student or pair
  • Fill a shallow tray or tub halfway with water and place it at a central station
  • Gather a set of small objects (plastic block, rock, sponge) near the water tray
  • Collect a stack of pennies or similar coins in a container by the station
  • Place paper towels beside the tray for spills
  • Print and organize student sheets: Predict & Test Recording Sheet and Boat Design Worksheet
  • Arrange students in pairs or small groups for the activity

Step 1

Introduction & Prediction

5 minutes

  • Gather students around the water tray and briefly explain buoyancy (“Will it sink or float?”)
  • Show one object at a time and ask for a class prediction
  • Distribute Predict & Test Recording Sheet and have students draw or write their predictions next to each object name

Step 2

Sink-or-Float Testing

7 minutes

  • In pairs, students place each object gently into the water and observe sink/float behavior
  • Have students record the actual outcome beside their prediction on the sheet
  • Discuss: Which predictions were correct? Why might some objects behave differently?

Step 3

Design Challenge Introduction

5 minutes

  • Explain the engineering task: build a boat from foil that can hold as many pennies as possible before sinking
  • Show example boat and demo placing pennies one at a time
  • Hand out Boat Design Worksheet and ask students to sketch their boat idea and predict how many coins it will hold

Step 4

Boat Construction

8 minutes

  • Give each pair a foil sheet to fold, shape, or crimp into a boat design
  • Encourage testing small adjustments (e.g., folded edges) to improve stability
  • Circulate to prompt thinking: "How can you make your boat wider or more balanced?"

Step 5

Testing & Reflection

5 minutes

  • Students place their boats in the water tray and add pennies one by one until the boat sinks
  • Record the total number of coins on the worksheet and compare to their prediction
  • Conclude with a quick share: Which design held the most? What would you change next time?
lenny

Slide Deck

Sink or Swim Boat Builders

A 30-minute STEM lesson on buoyancy and engineering design for 1st graders.

Welcome everyone! Introduce today’s lesson: Sink or Swim Boat Builders. Explain we’ll explore why things float or sink, then use foil to build a boat.

What Is Buoyancy?

• Buoyancy is the upward force water exerts on an object.
• It decides if something sinks or floats.

Define buoyancy and connect to students’ prior experiences (bathtub, puddles). Ask: “What makes a boat float?”

Predict & Test

  1. Look at each object and decide: sink or float?
  2. Record your prediction on your sheet.
  3. Test by placing it in the water and note what happens.

Hand out the Predict & Test Recording Sheet (#predict-test-recording-sheet). Show each object and ask for class predictions.

Foil Boat Design Challenge

• Goal: Build a foil boat that holds as many pennies as possible before sinking.
• Sketch your idea on your worksheet and predict the number of pennies it will hold.

Introduce the Boat Design Worksheet (#boat-design-worksheet). Show a simple foil boat example and model sketching.

Build Your Boat

• Shape your foil: fold edges up, flatten bottom, adjust width.
• Test small changes and improve your design.

Distribute foil squares. Circulate and ask: “How can you make it more stable?”

Test Your Boat

  1. Gently place your boat in the water tray.
  2. Add pennies one at a time until it sinks.
  3. Record the total pennies on your worksheet.

Remind students to add one penny at a time and count carefully.

Share & Reflect

• Which design held the most pennies?
• What features helped it float better?
• If you did it again, what would you change?

Invite a few pairs to share their results. Encourage positive feedback and ideas for improvement.

lenny

Worksheet

Predict & Test Recording Sheet

Name: ________________ Date: ________________

Instructions: For each object below, predict whether it will sink or float. Then gently place it in the water tray, observe what happens, and record the actual result. Finally, draw what you saw in the box provided.

1. Object: Plastic Block

Prediction (Sink or Float?): _______



Actual Result (Sink or Float?): _______



Draw what you saw:













2. Object: Rock

Prediction (Sink or Float?): _______



Actual Result (Sink or Float?): _______



Draw what you saw:













3. Object: Sponge

Prediction (Sink or Float?): _______



Actual Result (Sink or Float?): _______



Draw what you saw:













4. Your Own Object (Optional)

Name of object: ________________

Prediction (Sink or Float?): _______



Actual Result (Sink or Float?): _______



Draw what you saw:













Great job exploring buoyancy!

lenny
lenny

Worksheet

Boat Design Worksheet

Name: ________________ Date: ________________

Instructions: Use this sheet to plan, predict, and record how many pennies your foil boat can hold before sinking.

1. Sketch Your Boat Design

Draw your foil boat shape below. Include details like folded edges or a flat bottom.













2. Describe Your Design Features

What special features did you build into your boat? (e.g., folded rims, wider base)

  • Feature 1: ____________________________________________

  • Feature 2: ____________________________________________

  • Feature 3: ____________________________________________

3. Prediction

How many pennies do you think your boat will hold before it sinks?
Prediction: _______ pennies


Why do you think it will hold that many?
___________________________________________________________


4. Materials & Preparation

What size or shape was your foil sheet? (approx. 20×20 cm by default)
___________________________________________________________

List any adjustments you made before testing:






5. Test Results

Place pennies one at a time into your boat. Count carefully and stop when the boat sinks.

Total pennies held: _______ pennies


6. Reflection

  1. What part of your design worked best?
    ___________________________________________________________


  2. If you could build another boat, what would you change to hold more pennies?
    ___________________________________________________________


Great job engineering and testing your foil boat! Share your ideas and results with your classmates.

lenny
lenny