Science project

Layered Liquids (A Study in Density)

Difficulty Level




Safety Issues


Material Availability

All necessary materials are readily available.

Project Time Frame

3-4 weeks.


This project examines liquids of different densities. 

The goals of this project are:  

  1. To determine the comparative densities of various liquids.
  2. To discover the ways in which liquids of different densities are used. 

Materials and Equipment  

  1. Computer with internet access
  2. Digital camera
  3. Typical office/craft/hobby supplies (paper, pens & poster-board, glue, etc.)
  4. Large clear plastic straws.
  5. Modeling clay
  6. Medicine droppers or pipettes
  7. Salt
  8. Food coloring 

All materials can be found in your home, at local stores, or on ebay. 


Density can be described as the amount of material stuffed into a limited space. If two objects take up the same amount of space, but one weighs more than the other, the heavier object has the greater density. In this project we measure the densities of various liquids, and create a colorful demonstration.  

Research Questions 
  1. How is density measured?
  2. What are the practical applications of differences in liquid density? 
Terms and Concepts to Start Background Research 


Experimental Procedure 

  1. Research related materials (see bibliography below and search terms listed above)
  2. To make a graduated cylinder, set a small piece of clay on the table, and stick a straw into the clay so it stands straight. Make several more of these.
  3. Put some water in four different cups.
  4. Add food coloring so that each cup holds a different color liquid.
  5. Put two tablespoons of salt in one cup. Stir until dissolved.
  6. Put one tablespoon of salt in a second cup. Stir until dissolved.
  7. Leave the third cup with plain colored water.
  8. Use the dropper to put 10 drops of the saltiest water into the straw.
  9. Put 10 drops of the less salty water in the same straw.
  10. Add 10 drops of plain colored water to that.
  11. Try the experiment again, using different materials, such as sugar, honey, vegetable oil, dish soap, or whatever you can dream up.
  12. Write down and photograph all observations.
  13. Analyze the data.
  14. Interpret your results and describe your ideas in a detailed report.
  15. Include layered liquid samples in your science fair display.
  16. Show interesting photos taken throughout the course of the project. 


Wiki topic: “Liquid” and “Density” (A very cool 7-layer density experiment)

Internet searches of your own choosing: Search for any of the terms listed above (or make up your own phrases to search), and click on any results that interest you. Have fun surfing the net!

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Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state's handbook of Science Safety.

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