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What Makes Water Special?

Author(s): Nancy P. Moreno, PhD, Barbara Z. Tharp, MS, and Judith Dresden, MS.


The following materials, for groups of four, should be placed on a tray in a central location for collection by the each group’s Materials Manager. 

Teacher Materials

  • Bottle of food coloring (match marker color listed below to color selected)  
  • Marker 
  • Mineral oil or baby oil 
  • Water 

Materials per Student Group

  • Small labeled portion cup containing Mystery Liquid 1 (water) 
  • Small labeled portion cup containing Mystery Liquid 2 (mineral oil or baby oil) 
  • 8 eye droppers or pipettes (one pipette each for four Liquid 1’s and four Liquid 2’s, so there is no cross-contamination)  
  • 8 wooden toothpicks (four for liquid 1 and four for liquid 2, so there is no cross-contamination)  
  • 4 hand lenses or magnifiers  4 sheets of cm graph paper  
  • 4 sheets of wax paper to cover graph paper (Do not substitute plastic wrap.)  
  • Small portion cup containing diluted food coloring (see Setup)  
  • Crayons, colored pencils, or markers (use the same color as food coloring)  
  • Paper towels

Materials per Student

  • Copy of  “Do Your Liquids Behave?” page


  1. Cut a sheet of centimeter graph paper into fourths and cut wax paper to cover the graph paper for each student.

  2. Label small portion cups number 1 (for Liquid 1—water), and number 2 (for Liquid 2—mineral or baby oil).

  3. Pour about 20 mL of Liquid 1 (water) into each of 6 cups (adjust number of cups as needed for students to share) and repeat for Liquid 2 (oil). Be sure to conceal the identity of both liquids before the investigation.

  4. Place 120 mL of water into a plastic drinking cup or beaker and add six drops of food coloring. Divide this water into 6 small portion cups (adjust for your number of students/groups).

  5. Use either wooden toothpicks that have been soaked in water, or stained wooden toothpicks (do not have to be soaked). Plastic toothpicks often will have a static charge and are not suitable for this activity.

  6. Place all materials on a tray (except Liquid 2) in a central location to be picked up by each group’s Materials Manager.

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

The Environment as a Context for Opportunities in Schools
Grant Numbers: 5R25ES010698, R25ES06932

Houston Endowment Inc.

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education