The Great Density Experiment, or, The Best Science Project EVER

I don't even remember now how the kids ended up getting interested in density (if you do, please remind me!), but fascinated they were, so I planned a little unit of study for them to explore this property of matter.

The kids watched the density videos from Simple Science, memorized the definition of density (Density is the relationship between a substance's mass and its volume) and the formula to calculate it (d=m/v), and I attempted to guide them through the creation of an ocean in a bottle, a craft project that would be both cute and would demonstrate the interesting interaction between oil and water, but I didn't realize that the sand called for in the project is craft sand, and so I used SAND sand, and it was a total Pinterest fail:

The following day's density lab, however, was one of the most successful homeschool projects that we have ever done. I set up the following invitation--

--with the following supplies:

• pan balance scale
• measuring cups
• empty, clean peanut butter jars
• eyedroppers
• test tubes and test tube rack
• liquid watercolors
• mineral oil
• glycerin
• marbles
• container for water
• liquid starch
• corn syrup
• rubbing alcohol
• vegetable oil

The kids brought out their own science/math journals and pencils.

The kids' instructions were simple: explore the substances, making observations about their densities when compared to each other, and record everything in their notebooks (I'm working my way up to introducing them to lab notebooks, but hoping to do it gradually enough that Will won't rebel at all the writing required in keeping one).

The kids found this activity completely engrossing. Using the test tubes and peanut butter jars, they explored every single substance in every single combination possible, I imagine, constantly making discoveries and uncovering wonderful interactions:

water and liquid starch

mineral oil, colored water, and corn syrup

adding more corn syrup by eyedropper, and watching it fall to the bottom

Will kept adding to this one, and we kept being amazed by what happened:

recording it all in her notebook without a fuss--yay!

This is the notebook that she earned for completing the scavenger hunt at the Art Institute of Chicago.

Liquid watercolor and water

The colored water, administered by eyedropper, falls through mineral oil and bounces off of corn syrup:

ordering the substances by density in her notebook

Will reproduces Syd's experiment, with the same fascinating results.

When the kids found combinations that they especially liked and that seemed stable, I asked them to reproduce them on a larger scale, so that we could keep them to observe for a few days:

This was a gold-standard homeschool project, the perfect combination of concrete learning and free play that I know I'm going to be striving for in all our future projects. For now, we're leaving density and moving on to earthquakes, of all things, but this is a lab that will certainly bear repeating, with even more substances to choose from, the next time the subject comes up.

Here are some of the other resources that we used in our study of density:

• What Floats? What Sinks? A Look at Density
• Super Simple Science Experiments with Mass
• Mr. Wizard's World