Sand

Another day, another unit. Now we are learning and putting our attention to beaches and their sand. How did their sand come about? What are they made of? Why? There are many questions in this field and we are getting closer and closer to finding them out first hand. To do so, we created a new lab. The question driving this experiment is: Which beaches in south Maui have biogenic sand, and which have detrital sand? For this question, our task is to find two beaches each. Biogenic sand means that the sand was formed by life processes, meaning it may either be constituents or secretions of plants or animals. Detrital is loose fragments or grains that have been worn away from rock. The beaches I chose to identify were Oneuli Black Sand Beach and Makena Big Beach.

I hypothesized that Oneuli Black Sand Beach is detrital because there are rock cliffs and coral all surrounding the coved area. The sand on that beach is rough, like bits and pieces of rock, and dark in color. I think that Makena Big Beach is biogenic because of the texture and size of it's sand. The sand is very smooth, is super tiny particles, and light in color.

The materials we need for this testing:

• Pencil and Paper for documenting
• Camera 
• Cup to collect sand in
• Vinegar
• Pipette
• Safety Goggles
• Beaker(s)

Procedure:

1. Pick which beaches you think are detrital and which are biogenic in south Maui
2. Go to those beaches. 
3. Make observations of the area and the beach you are observing and write them down. Do this either in a journal or on a piece of paper. 
4. With your cups, collect some sand from each spot
5. Once back to your experiment area, put on your safety goggles! This is very important to protect your eyes.
6. Take one sample of sand and pour one layer of it into a beaker, enough to cover the bottom.
7. Then, suck vinegar into the pipette
8. Squeeze the vinegar out of the pipette and into the beaker with the sand
9. If the sand makes a crackling sound, that means it is biogenic, but if the sand does nothing and is just wet sand, then that means it is detrital.
10. Repeat steps four through eight for the rest of your sand samples

Aerial Views of Each Beach:

Oneuli Black Sand Beach

Makena Big Beach

On April 11th we visited both beach spots. There we collected our sand samples and took down our observations. At Oneuli Black Sand Beach, I observed that the beach was small and on the one side of it was a big cliff. The color of the sand was predominantly black but once you looked closer, it was a mix of whites, browns, reds, oranges, and beiges. Much of it resembled the color and texture of the cliff. One other thing about this beach is that the reef are alive, as apposed to Makena Big Beach where the reef was mainly dead. My observations at Big Beach were different. The beach was very big and the sand was very light in color. Just like at Black Sand Beach, Big Beach's sand also has hints of different colors in it. Colors like browns, beiges, whites, oranges, and some specks here and there of black. There was a similar cliff at Big Beach like at Black Sand, but it seemed to be too far away to be causing the sand to be the way it is.

Here are some photos of our sand collecting!

Big Beach

Big Beach

Mr. Marggraf Teaching Us How to Observe the Sand

Black Sand Beach

Mr. Marggraf Observing Black Beach's Sand

Once we got back into the lab, we tested the sand. When I put some of Big Beach's sand in a beaker and added the vinegar, it bubbled and made a crackling noise. These sensory observations were evidence that this sand was biogenic. Something a little similar but mostly a different experience, was testing the Black Sand Beach's sand. We put it into a beaker and then when we added the vinegar, the sand did not bubble, it was mostly just wet sand. With this, we thought that the sand was detrital, and for the most part it was, but then we started to hear something. It was a very faint crackling sound from the black sand. Although we were confused on what to call it, we came to the conclusion that the Black Sand Beach's sand was in fact detrital with a little part of it being biogenic. 

Although this lab was shorter than they usually are, I really liked it and also learned things that I had not know before. Before, I did not even realize that the beaches were so important and that they undergo some harmful things from constructions and storms. The thing that surprised me the most with this lab was when the Black Sand Beach's sand crackled but did not bubble. I was not expecting that. Some possible sources of error that we DID go through and COULD have gone through to change the results were: putting to much vinegar in the sand, we could have collected the sand in a weird part of the beach in which the sand is not usually like that, and we could have passed by the subtle crackling noise in the Black Sand tester.