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Activity: Observing Sand

NGSS Science and Engineering Practices:

NGSS Crosscutting Concepts:

NGSS Disciplinary Core Ideas:

Materials

  • 200 g sand
  • Small container to hold sand

 

Additional materials Part B

  • Balance
  • Folded paper
  • Weigh boats, plastic cups, or weigh paper (You will need a container for each sieve size plus one for the smallest size class, which passes through the last sieve. You may choose to use folded paper for each sample instead)
  • Sand sieves (at least three sizes)
  • If sand sieves do not have a bottom container attached, a separate container, tray, or piece of paper
  • Tables 5.5, 5.6, and 5.9
  • Fig. 5.26
  • (Optional) Sand grain size card

 

Additional materials Part C

  • Dissecting microscope or hand lens
  • Probe or toothpick
  • Tweezers
  • Petri dish
  • Additional Petri dish or small container
  • Permanent marker
  • White and black construction paper
  • Colored pencils
  • Sand grain size card or ruler
  • Tables 5.7, 5.8, and 5.10
  • Vinegar
  • Pipette
  • Magnet

 

Additional materials Part D

  • Sand samples from at least three sites
  • Small containers to hold sand, one for each site
  • Markers
  • Labeling tape
  • Table 5.11

Procedure

A. Sand collection

  1. Obtain at least 200 g of dry sand from a nearby coastline, lake, or river. Dry the sand thoroughly. Note: your teacher may have already done this step for you.
     
  2. If possible, obtain and record a description of the location where the sand was collected. You may want to note things such as
    1. the location on the beach where the sand was collected,
    2. the typical wave energy of the beach,
    3. the topography of the area, including the size and shape of the beach,
    4. the slope of the beach, and
    5. the season in which the sand was collected.
       
  3. Observe your sand. In your own words, describe the sand.
     
  4. (Optional) Obtain additional sets of sand samples from the same or different locations.

 

B. Investigate sand particle size and shape

  1. Review the steps in Fig. 5.26 for processing sand samples using sand sieves.
     
  2. Examine the sand sieves. If possible, calculate and record the particle size range of the sand particles that you will collect in each sieve in Table 5.9. This information is typically labeled on the side of the sand sieve. Be sure to include a size class for the sand that will pass through the finest sieve size (for example, if your finest sieve is 1 mm, sand grains passing through will be “less than 1 mm”). You may have more or fewer sieves than the number of rows given in Table 5.9.
     
  3. Categorize the type of particles that will be collected in each sieve in Table 5.9 using the sizes from the Wentworth scale in Table 5.5. For example, if the sieve is 1 mm, the mesh is collecting all particles greater than 1 mm. The minimum particle type collected according to the Wentworth scale is “very coarse sand”.
     
  4. Each portion of the sand will be collected and weighed separately.
    1. Label sample collection weigh boats, cups, or weigh papers for each size class that will be collected (the number of sieves you have plus an additional collection container for the smallest sand that goes through all the mesh sizes.)
    2. Pre-weigh each collection weigh boat and record in Table 5.9.
       
  5. Mix the sand sample to evenly distribute all of the grain sizes.
     
  6. Measure out 100 g of sand.
     
  7. Sieve your sand.
    1. Stack the sieves by mesh size, with the coarsest one on top and the finest on the bottom. If your sieves do not have a collection tray at the bottom, put a container, tray, or sheet of paper under the bottom sieve to catch the smallest grains of sand.
    2. Pour the sand sample into the coarsest sieve on the top of the stack (Fig. 5.26 A).
    3. Gently shake the sieve stack with a side-to-side or circular motion so that the sand particles travel through each sieve.
       
  8. Separate your sand samples.
    1. Choose a sieve to work with.
    2. Pour the sand collected into the sieve into a folded piece of paper (Fig. 5.26 B).
    3. Use the folded paper to pour the sand into the appropriately labeled pre-weighed boat, cup, or paper.
       
  9. Determine the percentage composition of sand sorted by particle size. Record each step in Table 5.9.
    1. Weigh each sand sample on the pre-weighed, boat, cup, or paper (Fig. 5.26 C).
    2. Calculate the mass of the sand by subtracting the mass of the pre-weighed boat from the mass of the sand and the pre-weighed boat together.
    3. Calculate the percent composition of each particle size in the total sand sample. The original sample was 100 g, so 1 g = 1% of the total sample by mass.
       
  10. Make a bar graph showing the percent composition of each sand size.
     
  11. Using a hand lens or dissecting microscope, examine the shapes of the particles within each size group.
    1. Describe the shapes you find for each size group in Table 5.9, using the terms from Table 5.6 or those.
    2. (Optional) Compare the particles to a sand grain size card to classify the particles by shape.
       
  12. (Optional) Determine sand size and shape for additional sand samples from the same or different locations.

 

C. Investigate sand source

  1. Obtain a 10 g sample of sand.
    1. Put the sample into a clean, dry Petri dish.
    2. Use the same sample of sand from Part A if possible. Do not use just one size classification of sand as resulted from the sieve procedure in Part B.
       
  2. Make predictions about the sources of sand that you will see in your sample based on your knowledge of the collection site.
     
  3. Using a dissecting microscope, view the sand at the lowest power. Be sure the sand is spread out in a thin layer in the Petri dish. You may use a probe or toothpick to move sand particles around. For light-colored sands, use a dark background; for dark-colored sands, use a light background.
     
  4. Try to identify at least five different types of sand sources in your sample. With tweezers, move one unique particle in your sand (for example, something that looks like it is part of an organism) or a number of similar looking particles (for example, particles of the same shape and color) to a separate Petri dish or other small container. In Table 5.10
    1. sketch and color the particle(s),
    2. describe the shape(s) of the particle(s),
    3. estimate the size of the particle(s) with a grain size sand card or ruler, and
    4. write any other notes.
       
  5. Sand that reacts with vinegar usually has a biotic component. Determine whether the sand created from this sand source has biogenic components by dropping 1–5 drops of vinegar with a pipette into a small sample of sand and watching to see if bubbles form. Record whether particles of this type are biogenic in the “notes” of Table 5.10.
     
  6. Sand that reacts to a magnet usually contains magnetite, an iron rich mineral. Use a magnet to identify any iron rich sand particles in your sample. Record which particles were magnetic in the “notes” of Table 5.10.
     
  7. Hypothesize the identity of the source of each type of sand particle. Record in Table 5.10.
    1. Refer to the descriptions of biogenic and abiogenic sand components in Tables 5.7 and 5.8. Remember that there are many components of sand not listed in these tables.
    2. Record your sand source hypothesis and reasoning in Table 5.10.
       
  8. (Optional) Quantify the percentage of each type of sand source in your sample.
     
  9. (Optional) Determine sand size and shape for additional sand samples from the same or different locations.

 

D. Mystery sand

  1. Your instructor will give you at least three samples of sand in small containers. While the instructor knows the origin of the sand, the exact origin is unknown to you.
     
  2. Label the sand samples A–C using permanent markers and labeling tape, if needed. Add additional labels if you have more samples.
     
  3. Obtain information about each of the mystery sites from your instructor. Site information may include
    1. pictures,
    2. the location on the beach where the sand was collected,
    3. the typical wave energy of the beach,
    4. the topography of the area
    5. the slope of the beach, and/or
    6. the season in which the sand was collected.
       
  4. Using methods and resources available to you from Parts B and C, describe the sand in Table 5.11 in terms of
    1. size classes,
    2. shape,
    3. source, and
    4. any other important notes.
       
  5. Make a prediction about the identity of each mystery site in Table 5.11.
     
  6. Obtain the actual identity of each mystery site and record in Table 5.11.

 

Activity Questions: 

Part B

  1. Describe the sand sample from Part B in terms of sand particle size and shape.

 

Part C

  1. Describe the sand sample from Part C in terms of sand sources. Include if you think, overall, your sample was biogenic or abiogenic and why.
     
  2. If you were not able to identify the source of all the particles that you observed in part C, describe what additional information would help you made a hypothesis about the sand source.

 

Part B and/or C

  1. Describe any manmade substances in your sand sample like plastic, glass, or other trash. How does the presence and abundance of these manmade substances reflect the location of your sample?
     
  2. If you observed manmade sand sources, estimate the total amount that you would find along the beach from which your sand was collected, either in terms of weight or number of particles. Explain how you made your estimation.
  3. Based on your understanding of your sand samples in terms of size, shape, and source, how do you think your sand was created?
     
  4. Many organisms live in a sand substrate, either on the beach or subtidally.
    1. What types of biological organisms might live in the sample you observed?
    2. What adaptations would organisms need to live in the sand you observed?

 

Part D

  1. After examining the mystery sand samples from Part D, what evidence did you use to make predictions about the location?
     
  2. What other information would have been useful when making predictions about the origin of the mystery sand?
     
  3. Did your predictions match the actual origins for the mystery sites? Explain why you think you predicted correctly or why you think you predicted incorrectly.

 

Activity Extensions

  1. How do you think the sediment would differ between a beach and a location offshore from the beach? Think of similarities and differences between the size, shape, and source of the sand you would expect to find in each location.
     
  2. How do you think temperate zone sands and tropical zone sands differ in terms of biogenic components?
     
  3. Forensic analysts often find trace evidence like dirt, fibers, and sand at crime scenes. They may not know where this trace evidence came from, but it is their job, as scientists, to do their best to determine where the unknown trace came from. Sand from a crime scenes bubbles when vinegar is dropped on it. Two suspects have been brought in for questioning.
    1. Suspect A lives on a volcanic beach in Hawai‘i, on the windward side that gets lots of wave action and is very steep.
    2. Suspect B lives on a wide flat beach in the Florida Keys, near a coral reef, with little wave action.

Do you think one of these suspects might have committed the crime? If yes, which one, and why? If not, why not? Describe the beach that the unknown suspect might live on.

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