Science Experiments for Kids

Liquid Density Test

Compare the densities of liquids and objects.
Compare the densities of liquids and objects.
©2007, Publications International, Ltd.

Try a liquid density test to find out whether all objects of the same size have the same density. This science experiment for kids tests the density of small objects by using the density of liquids.

What You'll Need:

  • Clear plastic cup or glass jar
  • Corn syrup
  • Salad oil
  • Water
  • Small objects (paper clips, buttons, macaroni, etc.)

Step 1: Fill a clear cup or jar 1/3 full with corn syrup.

Step 2: Fill the next third of the jar with salad oil.

Step 3: Add water to fill the top third.

Step 4: Drop small objects into the jar, and observe the level where they stop and float.

Objects will float at different levels depending upon their density in relation to the density of the different liquids. If the density of an object is greater than a liquid's density, it will sink through that liquid. If an object's density is less than a liquid's density, it will float on that liquid.

After experimenting a little, choose some new objects to test. Before dropping them in the jar, try predicting the level on which they will float or sink.

Go to the next page to learn about capillary action, or how water moves through the tiny spaces in fiber.

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