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  1. Sink or Float - Lesson Plan & Activity Sheets - Primary Grades
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Plastic Containers, sponges, aluminum foil, erasers, bar soap, popsicle sticks, fruit, crayons, pencils, rubber bands, paper clips, cotton balls, pennies, rock, index cards


Performance Objectives:

  •  TSW demonstrate an understanding of the terms “float” and “sink.”
  • TSW make predictions about an event and then test to see if their predictions are correct.
  • Using a graphic organizer, TSW record the findings of their experiment.
  • In written form, TSW express his or her thoughts on why certain objects sank and/or floated.

Resource Instructions

Do Now: 

What does it mean to sink?  What does it mean to float?  Describe three things that you have seen sink or float.  What else might you see sink or float?  For example, can people float?

(Write a brief journal entry on this topic using the information you have learned in our previous unit on water cycles.)


  1.  The teacher introduces the book “Who Sank the Boat?” by Pamela Allen, and asks students to predict what they think the book will be about.
  2. The teacher reads the book to the students using questioning techniques throughout the book to maintain interest and increase concept awareness.
  3. When finished reading, the class discusses what the book was about.  The teacher briefly introduces the terms “sink” and “float.”
  4. The teacher introduces a large clear container filled with water and explains to the class that they are going to make predictions about objects and then test them to see if they float or sink.      
  5. The teacher then introduces a PowerPoint presentation about “Floating and Sinking,” which contains media and colorful content in a highly visual and interesting manner.  Students are encouraged to participate during presentation of PowerPoint show.


  1.  The teacher re-introduces large water container to the class, reviewing the definitions of the terms float and sink.  Several objects that will not be used by the students are then introduced by the teacher, as the class collectively makes predictions as to whether it will sink or float.  She places the objects in the water to demonstrate the concept of sink and float.
  2. The teacher models procedure for experiment using a large chart-paper version of Activity Sheet #1:      1. Write name of object under “object” column  2. Make a prediction whether object will sink or float and circle it under the “prediction” column  3.  Place the object in the water.  4.  Record findings in “Try #1 Column” by writing the word “float” or “sink.”  5.  Repeat the process again and write findings in “Try #2 Column.”
  3. The teacher speaks to the class about appropriate placement of objects in the water and the importance of safety considerations.  The students are reminded that will not be able to participate if they are found splashing water purposefully or playing with the water in any way.  The students are also instructed to alert the teacher of any spills immediately, as to prevent any slip and fall accidents.
  4. The teacher splits the class into several groups by disseminating index cards to the class.  The cards indicate groupings by color, while also assigning students to a specific role within the group.
  5. The group member who is designated as the materials manager comes to the front of the room in order to obtain the materials necessary for the experiment.    
  6. The teacher checks for understanding by asking students within groups where the answers will go, how many trials to complete, etc.
  7. The students begin working within their small groups, testing and recording data, as the teacher circulates throughout the room checking for understanding and offering assistance.    

Medial Summary

The teacher asks the following questions while the students are working in order to summarize understanding:

  1.  What does it mean if the object is on top of the water?
  2. What does it mean if the object goes to the bottom of the water?
  3. What does it mean to float?
  4. What does it mean to sink?

What is a prediction?


  1.  As each group finishes, a group discussion is initiated by the teacher regarding, what sank, what floated and why.

Each group shares and compares their findings with the class, with the appointed group member being the presenter.






The students complete the following activity at home in order to extend and scaffold the activity completed in class.  Since there is water involved in the assignment, a special note is attached in order to notify the parents that additional supervision in required.

Assignment:  Students are to choose five (5) appropriate household objects that they think may skin or float (with the help of a parent.)  They are then to make predictions and record them.  Using a sink or tub, they are to text objects, recording their observations on the chart.  Student then write 1-2 sentence answer by reflecting and inferring , answering questions #1 and #2.



Throughout the unit, the students will continue to learn more about the concept of Sink and Float by addressing the following learning objectives:

  1. Students will learn that if an object’s shape is changed, that it may sink or float:  a. Students will make paper boats they will test to see if they sink or float.
  2. Students will make predictions to see how many pennies will be placed in their boats before it sinks.  They will record their answers.
  3. Students will change the shape of paper and foil paper.  They will test to see what happens when they change the shapes of both paper several times.  They will explain their results orally and in written form.
  4. Students will visit the website [] and play the “Sink Float” game about sinking and floating objects.



Student Assessment:

  1.  Each student then completes a “T-chart” using their knowledge of the data to record which items sank and which floated.
  2. Each student will then complete a journal entry about why they think things float and sink based on what they observed in the experiment and saw in the PowerPoint presentation.

The teacher will assess student performance by completing a “Sink or Float Rubric” and placing it in their portfolio.

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Posted by: S.Birnbaum

This is a great and thorough lesson plan. Thanks for sharing!