Lesson Plan:

Sink or Float

4.1 based on 15 ratings
July 9, 2015
by Rekha Mundkur
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July 9, 2015
by Rekha Mundkur

Learning Objectives

Students will learn which objects sink or float.


Introduction (5 minutes)

  • Gather students in a group and tell them that they will be learning about sinking and floating.
  • Show them a tub filled with water and the objects that will be tested.
  • Define sink as the action of an object when it becomes submerged in a liquid. Define float as the action of an object when it sits on the surface of a liquid.

Explicit Instruction/Teacher Modeling (10 minutes)

  • Have students guess which objects will sink and which will float.
  • Tell students that lighter objects are more likely to stay on the surface of the water and heavier objects are more likely to sink to the bottom of the tub.
  • Drop a couple objects into the water to show students how you would like them to place the objects, avoiding splashing, and showing them what you are looking for to determine whether the object floats or sinks.
  • Make a "float" and a "sink" pile and put your objects in their corresponding pile.

Guided Practice/Interactive Modeling (15 minutes)

  • Split your class into groups, one for each work station.
  • Have students test one object at a time, placing them into their own "float" and "sink" piles as they finish.
  • As groups finish, go around and check their "sink" and "float" piles for correctness.
  • Ask students to clean up any spills that may have happened, then to return to their seats.

Independent Working Time (10 minutes)

  • Hand out the Sink or Float? and Buoyancy worksheets.
  • Read out the definition of buoyancy from the Buoyancy worksheet.
  • Ask students if they have any questions.
  • Rotate around the classroom and assist struggling students.
  • Have students turn in their worksheets when done.



  • Enrichment: Advanced students can test more objects or complete extra worksheets, such as Sink or Float? 2 or Buoyancy 2.
  • Support: Pair struggling students with students who have a strong understanding of the concepts presented. Offer additional help with worksheets.


Assessment (5 minutes)

  • Review students' "float" and "sink" piles as well as their worksheets to assess their levels of understanding.

Review and Closing (10 minutes)

  • Gather students into a group.
  • Ask students if they were surprised by any of their results.
  • Review the concept of sink and float with them.
  • Read a book about sink and float if you feel your class needs more practice with the concept.

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