Sand Origins Lab

Introduction: There are two main origins of sand. One origin is biogenic, meaning it comes from something living. The other is detrital, meaning it is something that comes from non-living sources. You can test the sand to find it's origin by adding vinegar and observing the sample. Calcium carbonate (CaCO₃) is the biogenic material in sand. The calcium carbonate has a chemical reaction with the vinegar (CH₃COOH) creating, in part, carbon dioxide (CO₂) making the sand snap crackle and pop! The formula is CH3COOH+CaCO3---->Ca(CH3COOH)2+H2O+CO2. The amount that the sand reacts to the vinegar shows how much or if the sand has biogenic material.



Question: Is the sand at the Cove and Kam II mainly biogenic, or detrital?


Hypothesis: I think that the sand at the Cove will be mainly biogenic because of its light color, fine texture, and coral pieces. I think Kam II is mainly detrital because there is no shielding and the sand is a moderately dark tan color. If my hypothesis is incorrect about the Cove, it most likely has more detrital shielding than can be seen from the shore. If my hypothesis is incorrect about Kam II, the beach may have biogenic shielding that cannot be seen from the shore.



Materials:

• Paper/Journal



• Pencil



• Permanent marker



• Pipette



• Vinegar



• Small beakers



• Containers to take sand samples



• Tape to label containers (optional)



• Sand Samples



• Safety goggles
  

Procedure:

1. Take samples of sand you would like to test. Make sure you label them with the date and beach name.
   



2. When at the beaches you are taking samples from, jot down some observations of the beach structure and sand.
   



3. To test the sand, poor a thin layer of sand into a small beaker. (enough to cover the bottom)




4. Use the pipette to drip vinegar into the sample. Don't soak it; only add 20 drops dispersed over the surface of the sand.




5. Observe and record the reaction that the vinegar has with the sand. (CH3COOH+CaCO3---->Ca(CH3COOH)2+H2O+CO2)




6. Repeat steps 3-5 for every sample you test.
   

Data:

Field Observations:

The Cove: Like colored colar pieces and rocks, tan colored and fine grain sand, Lava rock shielding surronding beach.

The Cove looks similar to the beach shown here.

Kam II: No shielding, lava orcks to the south, and tan colored sand.

Kam II looks similar to the beach shown above.

Waipulani: Biogini shielding, coran, algea, medium grain sand, and light tan colored sand.

Sugar Beach: Armor, no other shielding, dark tan sand, and medium grain.

Data Analysis:

Conclusion:

















In this lab experiement, the goal was to determine whether the sand samples from The Cove and Kamaole II were biogenic or detrital. In my hypothesis, I thought that the sand at The Cove would be mainly biogenic because of its light color, fine texture, and coral pieces. This part of my hypothesis was correct. I also thought that Kamaole II was going to be detrital because of no shielding and the sand's moderatelty dark sand color. This part of my hypothesis was incorrect. It was found out that both beaches were biogenic. Both sand samples (containg calcium carbonate) from beach had noticable reaction (bubbles and cracking sounds) with vinegar (acetic acid).

















A possible source of error in this experiment could be that the bacteria in the samples could have triggered the reaction and therefore affected the result. Another error could be from vinegar which was diluted with water (not a pure vinegar).