Top 5 Density Columns for Science Education

A density column is a stack of liquids, sometimes with solid objects, that demonstrates the differences in densities of the substances. More dense substances go to the bottom, and less dense substances stay on the top. Eighth grade physical science students are AMAZED by these, and I think they work at any level when kids are learning about density or sinking and floating.

To make a density column, you’ll need a clear, straight-sided glass or vase, or a glass graduated cylinder. Here are my favorite examples of density columns you can make!

 

1. Steve Spangler’s Seven-Layer Density Column

This is the density column that started it all. Layers of corn syrup, water, vegetable oil, dish soap, rubbing alcohol, lamp oil, and honey form a beautiful striped column. Careful technique is key!

Learn how to make Steve Spangler’s Seven-Layer Density Column.

2. Steve Spangler’s NINE-layer Density Column

You think seven layers was cool? Try this advanced density column that uses nine different liquids and seven different solid objects! Wow!

Instructions for the Nine-Layer Density Tower

3.  Steve Spangler’s Light Ice, Heavy Water

Yes, another Steve Spangler entry. This one is a lot more subtle, so is a cool divergent follow-up to the density columns above. It’s also really beautiful! You’ll need food coloring, baby oil, the “mystery liquid” (spoiler: it’s vegetable oil), an ice cube, and patience.

Learn how to build Light Ice, Heavy Water here.

 4. Lava Lamps

A lava lamp is a moving density column that contains two substances, water and wax. The wax is more dense than water when it’s cold, so it sinks. When the wax is heated by the lamp at the bottom, it expands just enough to be less dense than the water, so it floats! Explaining a lava lamp is a great test of understanding of density and thermal expansion.

5. Homemade “Lava Lamp”

You can make this in any transparent container. Note that this lava moves for a different reason that the original lava lamp! Here, the blobs of water become less dense when they fill with bubbles of carbon dioxide from the dissolving tablets. The blobs rise through the oil to the top, where the bubbles break. The blobs are then more dense and sink!

Note also that Lane says the water and oil don’t mix because they are different densities, which he equates with polarity differences. These aren’t quite the same thing. Both contribute to the choice of these liquids for the “lava lamp,” however.