ACTIVITY: Source of Hawaiian Sand

NGSS Science and Engineering Practices
NGSS Crosscutting Concepts
The activity below draws from the content in the page Weathering and Erosion.


Image caption

Fig. 1. A sideways glance along the surface of the beach reveals an array of colors amongst the grains.

Image copyright and source

Image courtesy of Max Pixel


In a handful of sand, there can be many colors (Fig. 1).


Why are there different colors of sand grains in Hawai'i?


Guiding Questions:

  1. How do different types of sand form?
  2. Why is sand color different from beach to beach? 


In this activity, you will make observations about the effects of weathering. You will conduct an experiment to investigate whether sand collected from around Hawaiʻi is volcanic or biological in origin.

Note: There is an interactive sand matching game as a Further Investigation that can also be used before this activity.


  • Sand samples from different beaches—at least 3 samples (Hint: preferably black sand, white sand, and one with mixed colors)
  • Small bowl or dish
  • Magnifying glass
  • White school glue (or any glue that dries clear). Clear tape can also be used.
  • White distilled vinegar
  • Teaspoon (or small spoon)
  • Sand inquiry Student Worksheet and Teacher Guide (attachment below)


    This teacher guide follows the procedure written here and in the student worksheet with additional instructions and guidelines. We highly recommend starting this activity by introducing the Phenomenon, Inquiry, and Guiding Questions from the top of this webpage.

  • Optional: Extra pages to explore additional sand samples

Vinegar Test:

  • Vinegar is a weak acid that reacts with and dissolves calcium carbonate. 
  • The shells and skeletons of many marine invertebrates (like corals, urchins, clams, plankton, etc.) are made of calcium carbonate. Calcified algae also contain calcium carbonate.
  • Vinegar releases bubbles of carbon dioxide when it dissolves calcium carbonate. If there is no calcium carbonate present when you add vinegar, there will not be any bubbles.


  1. Follow your worksheet to explore and observe your sand samples using a toothpick and magnifying glass.
  2. Glue sand from each location onto your worksheet, and answer the preliminary questions.
  3. What would happen if you add vinegar (a weak acid) to
    1. biological sand (one with pieces of shells, coral or algae)?
    2. volcanic sand (sand from volcanic rock)?
  4. Test your samples to determine the source of sand. Record your findings in the worksheet table.

Sample #1: White Sand

  1. Place a teaspoon of white sand into a bowl or dish. 
  2. Slowly add a teaspoon of vinegar.
  3. Observe and record the reaction.

Sample #2: Black Sand

  1. Place a teaspoon of white sand into a bowl or dish.
  2. Slowly Add a teaspoon of vinegar.
  3. Observe and record the reaction.

Sample #3: Mystery Sand

  1. Place a teaspoon of white sand into a bowl or dish.
  2. Slowly add a teaspoon of vinegar.
  3. Observe and record the reaction.

Additional Samples

  1. Explore more sand samples using the additional sand inquiry pages!


Activity Questions:

  1. What differences did you observe between the different colors of sand?
  2. What do the differences you observed tell you about the source of that sand?
  3. If one sand sample bubbled a little bit but the other sample bubbled a lot when you added vinegar, what would this tell you about the amount of biological material in each sample? 
  4. How do you think the sand got to the beach?
  5. Did you see anything else in the sand? Describe any items that do look biological or volcanic.
  6. How do you think non-sand items got to the beach?
  7. Do all beaches get their sand in the same way? Explain your ideas.

Further Investigations:

  1. Map out the different sand beaches around Hawaiʻi. Glue/tape sand samples to a large map.
  2. Bonus Feature: Interactive Sand Game!

Discover how the sand is formed! Build your knowledge by playing an interactive game and  match the different types of sand to the beach.

You may need to enable Flash or change browsers to view the interactive feature below. 

Note: If you cannot view the entire interactive on your screen, press Ctrl-Minus (-) on a PC and Command-Option-Minus (-) on a Mac to zoom out.


Related Conversations


As an additional source, attached it the original SEA lesson plan that includes some suggested assessment tools!

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Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawai?i, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.