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KSAT Kids Home Science: Rainbow in a Jar

A great way to learn about the density of liquids!

SAN ANTONIOEditor’s note: This story was published through a partnership between the STEMToyExpert.com and KSAT.

Hello parents, teachers and students!

Are you looking for something fun to do at home that has a little bit of science behind it?

Well, check out this awesome at-home experiment. Science enthusiasts and educators at the STEMToyExpert.com put this together.

Generic image of a jar.
Generic image of a jar. (KSAT)

Rainbow in a jar

This simple science experiment is not only very visually appealing, but it’s also a great way to learn about the density of liquids. Warning though, this one could get messy so make sure kids are in some old clothes and you might want to take it outside!

Questions to ask beforehand:

  • Which liquids they think will be heaviest?
  • Which ones will be lightest?
  • Why do they think that?

Here’s what you’ll need:

  • A glass jar
  • Food coloring
  • Various liquids like honey, corn syrup, dishwashing liquid, olive oil, rubbing alcohol and water.

Procedure/Instructions:

  • Use the food coloring to make all your liquids a different color. A dropper comes in handy here, but if you don’t have one you can manage without.
  • Slowly add each liquid to the jar (pouring into the middle of the jar is best).
  • Soon, you’ll have different layers of colored liquid forming your very own rainbow in a jar.

You might even get them to draw a diagram of what they think the jar will look like at the end. They can compare this with the experiment results to see if their prediction was correct.

It might also help to talk to your kids first about what density is and how materials are all made of different amounts of molecules. The more molecules a liquid has, the heavier it will be.


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