Material Type:
Lower Elementary
  • Float
  • Science
  • Sink
    Creative Commons Attribution Non-Commercial
    Media Formats:

    Education Standards

    Sink or Float

    Sink or Float


    This is a science lesson that helps students make predictions, complete expirements, and analyze data on what makes an object sink or float when placed in water. 


    This science lesson is targeted for 1st grade students learning about whether objects sink or float. Students will be introduced to the topic, complete activities, expirement, and complete an assessment.

    • This lesson will be completed over 5 days in 30 minute increments.
    • This lesson will be completed face to face in the classroom.



    First Grade

    Standard 3: Physical Science. Students will gain an understanding of Physical Science through the study of the forces of motion and the properties of materials. 

    Objective 2: Analyze objects and record their properties. 

    b. Predict measurable properties such as weight, temperature, and whether objects sink or float; test and record data.


    Background for Teachers

    Teachers need to be able to explain the difference between floating and sinking. Teachers will need to know characteristics of objects that make them sink or float (ie size, density, buoyancy).


    Step 1 - Goals and Outcomes

    • Students will be able to identify characteristics that make an object float or sink.

    • Students will be able to predict whether an object will sink or float.

    • Students will make an object that will float.

    Step 2 - Planning Instruction

    • Prior to this lesson, students will need to have an understanding of making predictions, observations, and comparing data and results.

    Strategies for Diverse Learners

    For advanced learners they will have the opportunity to make changes to a floating object in order to make it sink. They will find what characteristics make certain items float and change it just enough to sink.

    Step 3 - Instruction

    Introduce the topic and lead a discussion on objects that sink or float and the characteristics the objects might have in common. Read the book, “Who Sank the Boat” and come up with questions that we need to know in order to build an object that will float.

    Watch the following video as a class to introduce the topic:

     Students will have the opportunity to complete the following computer activity: 

    Students will work in groups predicting whether objects provided will sink or float and then test the objects in water, and record their discoveries in their journals. Students will talk about their findings and share with one another why they think certain objects sink or float and how their findings differed from their predictions. 

    For a community/life connection I would ask a swimming teacher to come in and talk to the class about sinking and floating and ways to make our bodies float in the water and water safety.


    Students will test their objects that they believe will float. As a class the objects will be tested and students will explain why their object should float.


    Step 4 - Assessments

    Student’s knowledge on the topic will be assessed by ongoing informal classroom assessment such as thumbs up or down and contribution to classroom discussions.

    Students will make predictions in their journals when conducting experiments on different objects and whether they sink or float. Students will be assessed on their ability to explain the different characteristics and being able to explain why their prediction may differ from the outcome of the expirement.

    For the final product/project the students will build an object during center time that should float. They can use objects and knowledge that was learned in class about what makes an object float. As a class we will test our objects and discuss with the class how we made our objects and discuss reasons why they did float or sink.