What Objects Sink and What Objects Float


Michael Young

Jane A. Neil School

8500 S. Michigan


(773) 535-3000




The objective of this mini-teach is to explore the problem of why certain objects sink and why certain objects float with Severe and Profound Non-categorical Special Education students.




For an individual up to a group of five students you will need an aquarium or a large bowl of water to test objects, such as: small rocks, plastic boats, apples, nails, wood, eggs, or crayons.  




Have the student or students try to predict what will happen if they pour the cup of rocks or sand and gravel into the aquarium or bowl which is filled with water. Next have the student or students pour the rocks or sand and gravel into the aquarium or bowl and observe what happens. (Note: some of the students may need help such as hand over hand assistance, or gestures.) Next have your student or students try to predict what will happen when a plastic boat a rubber ball or a block of wood is placed into the aquarium or bowl filled with water. Your student or students should now place the plastic boat, rubber ball or block of wood into the aquarium and observe what happens.


Performance Assessment:


The performance assessments that I use for students with such severe disabilities are teacher observation, their ability to follow directions, their enthusiasm and their willingness to learn. Students should try to the best of their abilities to perform this experiment to see which objects sink and which objects float.




If an object is heavy for its size, it will sink. If it is light for its size, it will float. A brick is heavy for its size, so it will sink. A piece of wood the same size will float.




Complete Book of Science


Grades 1- 2

American Education Publishing

Ashland, O.H. 44805



Discovering Density

Great Explorations in Math and Science

(GEMS), Lawrence Hall of Science,

University of California at Berkely, 1988, 91, 93