Neutral Density Exploration

Most STEM teachers know the importance of letting students explore, but usually it’s the students who struggle with “exploration”. We have created a a post with ideas, activities, and experiments geared toward exploration, and here is one of those, which can be done with relatively little prep:

Materials
one container (small bowl) per group full of the following:

  • pennies
  • washers
  • rubber bands
  • straws
  • styrofoam pieces
  • balloons (these will pop, so make sure each group has several)
  • paperclips
  • Legos
  • small wooden blocks
  • any other simple items you can think of

one clear glass or plastic pitcher filled about 3/4 full of water

Procedure
Put the students in groups of 3-5 and give each group a set of materials (above). Explain neutral density (when something neither sinks nor floats in water). Tell the students they have to design something that will sit in the middle of the pitcher that does not float to the top or sink to the bottom.

Sit back and let them explore different ways to do this. You may want to incorporate some rules about not being able to answer any questions for the duration of their exploration. Encourage them to keep a journal and write down any questions that they have before trying to solve them as a group by experimenting. If their questions remain unanswered/unsolved at the end of the time period, you may either answer them yourself or encourage the students to do their own research at home.

This could be turned into a project that expands into several days’ worth of concepts that include outside (independent) research and a journal recording the process.

If you like this STEM Challenge, check out others here.