Ever wondered how to float coloured water on top of coloured water? OR maybe why you float higher in the sea compared to your swimming pool? Well, this little dastardly density experiment shows you why these happen.
Density is a measure of how much ‘mass’ (or matter) there is in a specific space (volume). You will make coloured water that has different masses by dissolving sugar in them. You will then layer these ontop of each other to create a mini-Jupiter in a test tube!
  • Jupiter-test-tube-materialsJug of water, small containers
  • Food colouring
  • Sugar cubes, pipettes
  • 1 x Terrific Test Tube


Water spilt on the ground can be a slip hazard, mop up any water
quickly if spilt on fl oor.

  • jupiter-test-tube-step-1Mix the food colouring into the cups and place the sugar cubes beside each cup.
  • Suggested cubes:
    1-yellow, 3-red, 6-green and 9-blue
  • jupiter-test-ube-step-2Add the blue solution fi rst. This should have the greatest density (since you added the
    most sugar to this colour).
  • jupiter-in-a-test-tube-step3Add the green solution CAREFULLY and
    drop wise next.
  • Since it had less sugar in it, it should be lighter
    and sit on top of the blue solution.
  • Tilt the test tube slightly while you add the
    green solution on top of the blue.
  • This should
    prevent it from falling into the blue solution
    and mixing.
  • jupiter-in-a-test-tube-step4Keep adding each colour until
    you have the lightest solution on
    the top (yellow).

Check out the ‘Wacky Science’ video of this experiment. It is currently ‘In Production’, so check back soon…..

Wacky Science Ep


This experiment examines the concept called density. Density is a measure of how much mass an object has in a certain amount of volume. It is often shown as a mathematic equation as shown below.

Objects (solids, liquids and even gases) that have a LARGE mass in a set volume are ‘heavy’ and those that have a SMALL mass in the same amount of volume are ‘light’.

Consider the two balls below that are the SAME size (same volume). The bowling ball has MORE mass compared to the soccer ball (mostly air). As you can see, the object that has MORE mass in the same volume has a higher density and is HEAVIER. (more dense).

 density ball pic


The bowling ball would sink in water and the soccer ball would float due to their different densities. Our liquids are very similar. The volume of water used was the same BUT they had different amounts of sugar dissolved in them. This gave us 3 liquid with different densities. The heaviest liquid sank to the bottom of the test tube, the  lightest liquid floated on top.


Red Sea density: Examines the saltiest sea in the world. You can float REALLy high in this sea!


Mass: This is amount of matter that makes up an object. The ‘stuff’ or particles often referred to as atoms.

Volume: Is the three dimensional space of an object.

Try our Bright Spark Experiment Guide Jupiter in a Test Tube Cover2

We have created an experiment guide called ‘Jupiter in a Test Tube’ that explores this experiment like this page BUT has many more ‘goodies’ to investigate such as:

– Greater ‘in-depth’ explanations

– Another experiment similar to this one but with a greater level of challenge

– Explanations of how this experiment can be done in the scientific format called ‘Scientific Method’ (aim, hypothesis, variables, risk assessment, etc )

– Graphing opportunities

– Description and links to REAL life examples of density (making learning REAL)


Perfect to extend your budding scientist, homeschool child or students in your classroom.