Density Control

Objective:  Control the gravitational behavior of liquids and solids based on their densities. Create layers of sugar water with varying densities, then find an object that will sink to a depth you are able to predict beforehand.Density Control

Example of practical application:  Humans are able to control whether submarines float or sink, and to what depth, based on the density of the vessel versus the water it is in. Also, certain gases are less dense than air, which makes them capable of carrying additional weight up into the air; however, the object cannot continue to rise indefinitely because air becomes less dense the higher you go.

PrerequisitesDensity Diffusion Drink, Density of an Object

10 tbs sugar
Graduated cylinder
Tall, narrow glass
Digital scale
Small object (Step 4)

ProcedureDownload the Word document.

  1. Watch the video of me doing this lab at:
  2. Create four color-coded samples of sugar water with increasing densities. The Density Diffusion Drink prerequisite above shows you how to do this step.
  3. Record your measurements and calculations in a data table with the following format:




    Density (g/mL)





















  4. Obtain an object with the same density as your second or third density sample (NOT your highest or lowest).  Hint: dry beans are handy for this, but they gradually take on water, which increases their density. The Density of an Object prerequisite above shows you how to do this step.
  5. Record your measurements and calculations in your data table.
  6. Write a hypothesis predicting the layer you expect your object to settle on. The object should stop sinking when it reaches a layer of its own density. *The top and bottom layer don't count because that's simply sinking or floating, not controlling density.*
  7. Layer the water samples in the tall glass (see Density Diffusion Drink).
  8. Release your object onto the top of the liquid with no free-fall force. Where does it stop sinking?
  9. Write the result and conclusion of your hypothesis.
  10. If your result doesn't match your hypothesis, something went wrong in your measurement or calculation. Or perhaps you used an object that absorbs water and its density changed. Try again till you get it right and feel the victory of controlling density.

Just Think!
Could you use density control to invent something that allows people to hover in air or water? Could you create a liquid dense enough to hold you afloat in a bathtub? What else could be invented with this technology?