Dunking for Density Investigation (Part 2/2)

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SWBAT apply the concept of density to floating and sinking.

Big Idea

Sink or swim? Students manipulate densities of mini-submarines to make them sink, float and suspend.


This is the second part of the multi-day lesson Dunking for Density.

Diving! Your submarine is descending to explore to the deep, dark depths of the ocean...how does this submarine sink and then rise from the depths again to reach daylight? Density is not only a rich physical science concept with respect to understanding matter, properties of matter and identification of matter, but it is also a perfect link between physics and chemistry. Sinking, floating and buoyancy come to play when students explore how mini-submarines float and sink.

This lesson assumes students have prior knowledge of mass (Measurement: Mass), volume (Measurement: Volume) and density (Measurement: Density) as fundamental properties of matter (Mystery Substances: Properties of Matter Investigation). Throughout this investigation, students  access learning objectives related to the "Matter and Its Interactions" (MS-PS1) and the "Forces and Motion" (MS-PS2.A) Disciplinary Core Ideas. These core ideas require students to be able to analyze and interpret data on the properties of substances and understand concepts related to forces.

Density data also relates to Common Core Mathematics Standards in the Ratios and Proportional Relationships and Measurement and Data domains. As an understanding of density develops, students are better able to understand proportional relationships, which provide information about the magnitude of properties and processes and recognize that scientific relationships can be represented through the use of algebraic expressions and equations (CCC). While students conduct their investigations, they produce data to serve as the basis for evidence that meet the goals of the investigation (SP3), apply mathematical concepts and processes (SP5), engage in investigation to collect, analyze and interpret data (SP4) and construct written arguments supported by empirical evidence and scientific reasoning (SP7). The arguments practice connects to Common Core Language Arts Standards when they write conclusion arguments in Part 2 of the lesson.

The Dunking for Density Investigation series of lessons is a scientific inquiry investigation taught over the span of several days. To help manage the magnitude of this activity, you will find the project split into 2 parts.

  • Part 1 includes the ENGAGE and EXPLORE components of the lesson; Time: 1-2 50-minute lessons or equivalent block period. 
  • Part 2 includes the EXPLAIN/EXTEND and EVALUATE components of the lesson; Time: 2-3 50-minute lessons or equivalent block periods.


The EXTEND stage allows students to apply new knowledge to a novel situation. The novel situation in this case occurs in the form of several extension options:

1) Modify the original question to solve a different problem. For example:

How does changing the volume affect the density of the mini-submarine?

How does the shape affect the density of the mini-submarine?

How do different liquids affect the buoyancy of the mini-submarine?

2) Complete additional density calculations that require advanced algebraic thinking: Density Practice Student Handout.

3) Complete an additional investigation designed by other students: Floating and Sinking Soda Experimental Design Plan.

4) Explore density by completing an extension activity like these: Ice Density Extension or Density Column Extension. For a picture of a lovely density column click this: Density Column - Student Exemplar.

Here, a student talks about what extension opportunities mean to her:


90 minutes

The EXPLAIN stage provides students with an opportunity to communicate what they have learned so far and figure out what it means. The EVALUATION stage is for both students and teachers to determine how much learning and understanding has taken place. For this lesson, the EXPLAIN and EVALUATE stages are combined in order to encourage students to explain their learning for the purposes of evaluating their understanding.

During this state of the lesson, students create a line graph on the Dunking for Density Experimental Design Plan to display their data and observe any trends that they might be able to explain in the final communication of their results. Students then access the instructions to help them complete the Dunking for Density Final Project and Dunking for Density Final RECALL Lab conclusion: Dunking for Density Investigation To Do.

The primary ways I evaluate student learning are two-fold:

1) Students summarize the investigation and analyze their results by completing a final RECALL Lab Conclusion. For the associated lesson, visit: Writing a Recall Lab Conclusion (Part 1/2) and Writing a Recall Lab Conclusion (Part 2/2). The Dunking for Density Investigation Final RECALL Lab Conclusion - Student Exemplar shows an advanced example of a RECALL Lab Conclusion for this investigation.

2) Students create a final labeled diagram to explain why objects float, sink or suspend due to density and buoyant force. Dunking for Density Investigation Final Project - Student Exemplar is an advanced example of of the final diagram project.

For additional discussion of providing multiple opportunities for assessment using different modalities, visit: Multiple Assessments Using Multiple Modalities