Laney Lee

Sink or Float Density Experiment




Are you struggling to make density “click” for your students? If so, bring science to life with this easy to prepare, hands on sink or float density experiment!


I was super nervous to implement this density lab in my rowdy middle school classes of all boys, but it turned out that a few manipulatives actually made them a lot calmer, engaged, and on task. Who knew what a few paperclips could do? I’d highly recommend this activity to anyone teaching weather, earth’s layers, or any other density related topic!


Using this investigation, students will examine 10 different items and make predictions about whether they will sink or float. Then, students will test the objects and make conclusions about the densities of the objects as they relate to the density of water.


Who is this resource for?

This resource can be used by classroom teachers, tutors, and parents of students in grades 6-9. Make sure you have enough time to prepare a few materials ahead of time, and be sure to check with your department to see what’s already available at your school!


Materials Required for this investigation:

  • A container of water
  • 10 small items (a list of suggested items is included)


What’s Included?

  • Student Sheet (in both printable PDF and digital Google Doc)
  • Teacher tips
  • Accompanying Presentation (Google Slides)
  • Printable Procedures
  • Answer key


Purchase includes a printable PDF file in color with answer key. On page 2 and 3 of this resource you will find a link to digital files. You will be able to copy these file and use it with Google Classroom or any other paperless initiative.


Please take a look at the preview file to see more of this resource.


More questions?

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NGSS Standards covered by this Sink or Float Density Experiment:

Collect data to provide evidence for how the motions and complex interactions of air masses result in changes in weather conditions. Emphasis is on how air masses flow from regions of high pressure to low pressure, causing weather (defined by temperature, pressure, humidity, precipitation, and wind) at a fixed location to change over time, and how sudden changes in weather can result when different air masses collide. Emphasis is on how weather can be predicted within probabilistic ranges. Examples of data can be provided to students (such as weather maps, diagrams, and visualizations) or obtained through laboratory experiments (such as with condensation). Assessment does not include recalling the names of cloud types or weather symbols used on weather maps or the reported diagrams from weather stations.
Develop a model based on evidence of Earth’s interior to describe the cycling of matter by thermal convection. Emphasis is on both a one-dimensional model of Earth, with radial layers determined by density, and a three-dimensional model, which is controlled by mantle convection and the resulting plate tectonics. Examples of evidence include maps of Earth’s three-dimensional structure obtained from seismic waves, records of the rate of change of Earth’s magnetic field (as constraints on convection in the outer core), and identification of the composition of Earth’s layers from high-pressure laboratory experiments.


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