• observing  samples;
• predicting  locations of various types of sediment;
• identifying  independent variables;
• designing descriptive data collection  criteria;
• collecting  samples;
• graphing and quantifying  data;
• analyzing  data.

Science:

• Grade Four: 4.1, 4.8
• Grade Five: 5.1, 5.7
• Grade Six: 6.1, 6.2, 6.6
• Earth Science: ES.1, ES.2, ES.8, ES.9

Mathematics:

• Grade Four: 4.11, 4.12, 4.13
• Grade Five: 5.3, 5.11, 5.17, 5.20
• Grade Six: 6.7, 6.9, 6.10, 6.18
• Grade Seven: 7.21, 7.23, 7.25
• Grade Eight: 8.18

    Sediments are often classified by size as follows: clay less than 0.004 mm), silt (0.004-0.062 mm), sand (0.062-2 mm) and granules or pebbles (larger than 2 mm). Sand is usually classified further as fine, medium or coarse.

    There are several different kinds of minerals in typical beach sand, including quartz, magnetite, garnet, mica, feldspar and limestone, as well as particles of shell, plastic, and sometimes coral. The difference in size, shape and density of these materials determines how they are moved by water and wind along the shoreline.

    Shorelines are molded by the energy from moving water (waves and currents) and wind. The amount of energy affecting a site determines, to a large extent, the sizes of particles present. Denser and larger particles require more energy to be moved than less dense and smaller particles. Smaller particles stay suspended in water until the water movement slows enough to let them settle out. Thus, larger sand particles are moved and deposited by large waves on an open beach but are rarely carried up into tidal creeks by the gentle currents and tides. Silts and clays collect among the roots and stems of plants forming marsh mud.

    Storms sometimes move dense sediments onto a beach. Such deposits may be revealed as dark bands if one digs a trench in the sand. The strength of a storm may be inferred by the width of the dark band.

    Long shore currents typically mave sediments along shorelines. Current direction may change during the year. The movement of coastal sediments is affected by man made objects such as docks and jetties, which disrupt the flow of sediments along the shore, thereby altering the natural coastline. This can cause accretion (build up) in some places and erosion in others.

• large-mouth, straight sided plastic jars with lids (2 per group)
• 1 very large jar, preferably long and narrow
• gardening trowels
• labels for jars
• permanent markers
• rulers
• copies of data sheet
• clipboards, pencils (1 per student or group)

Before the Trip:

   
1. Collect enough wide-mouth, straight-sided, plastic jars (such as those used for peanut butter) to have two per sample site.
      
2. Visit the park to locate at least four areas where the shoreline sand or soil is under the direct influence of wind and/or water. These areas might include:
   
   • Bay or river beach in the area the waves wash over (swash zone)
   • Bay or river beach above the line of debris left by high tide (wrack line)
   • Bay side of sand dune
   • top of sand dune (collect from boardwalk)
   • backside of a sand dune
   • tidal marsh
   • edge of tidal creek
   • bottom of a woodland stream
   • edge of a pond
   List the sites and give each an identifying name. Collect a few small samples of different sediments. Mark the jars with the site names.
      
3. Discuss with the class the basic types of sediments. Describe the sites to be visited and have the students describe the types of sediments they would expect to find at each.
      
4. Students name factors that might affect particle size at a site. List these on the board and then come to a consensus on which factors (two to six) will be investigated on the field trip. Some factors might be: wave action, fetch, current speed or plant density.
      
5. Explain that each of the factors they have listed can be considered an independent variable that might have some effect on the dependent variable, sediment particle size.
      
6. Share the samples you collected with the class. Make observations on the texture, smell, and appearance. Which samples might be silt?  Clay?   Sand?
      
7. MaKe small group sampling team assignments. Give each group a copy of the park map with the sampling site locations identified. The groups then predict what type(s) of sediment will be found at each site.
      
8. Assign each group the task of designing an original rating scale for one of the independent variables. Criteria for the scale must be readily observable or quantifiable. For example, for a wave action scale of 1 to 5, 1 could be glassy calm, and 5 could denote white caps.
      
9. Discuss proposed Scales. Correct and improve as necessary. Develop data sheets (see example provided), fill in rating criteria designed by groups, and make one copy for each group.

   
1. Break the class into small groups for on site collecting.
      
2. At each collection site, students half fill the appropriately labeled jars (2 per site) with sediment samples.
      
3. Students rate the independent variables for each site on their data sheets.

Time Required at the Park:
    Allow about 1 hour in the field, but duration depends on number of sites visited and time required to reach each site; any daylight hours, low to mid tides best at some locations.
Time of Year:
    Any time.

   
1. Prepare a large master reference sediment jar by half filling one jar with equal amounts of sediment collected at each site. (Groups collected two jars at each site. Use one of those jars from each group for this step.)
      
2. Fill the master reference and all of the remaining sample jars with water to within 1 cm of the top and screw on the tops. Shake them vigorously until all of the particles are well-separated and suspended. Set them side-by-side in a well-lit place in the classroom where they can be studied by the class without being moved again.
      
3. The next day, study the sediment layers in the master reference jar with the class. The top layer has the lightest and finest particles and the bottom layer the coarsest and heaviest particles. Create a particle size category scale by numbering the layers, starting the numbering with the top layer. (#1 represents the finest sediments and the highest number - the total number of layers - represents the heaviest sediments.)
      
4. Each team carefully compares the layers in their sample jar with the layers in the master reference jar and assigns the corresponding particle size category scale value (layer number) to each layer in the sample jar. They should write these values on their sample jar.
      
5. The teams next measure and record the depth of each sediment layer and the total sediment depth in their sample jars.
      
6. From the measurements, they determine the percentage of each sediment component by dividing each layer depth by the total sediment depth in the jar, then converting that fraction to a percentage.

   Using the sample given:
      #3    2 cm/8 cm = .25
      #4    1 cm/8 cm = .125
      #5    1 cm/8 cm - .125
      #6    4 cm/8 cm = .50

      

7. Teams next prepare bar graphs for their samples showing the percentage of each sediment component. (In the example shown, the numbers of the X-axis correspond to the particle size scale determined for the master reference jar.
      
8. Discuss the results to determine which sites(s) had the smallest particles (silt and clay), which had the largest particles, and which had the greatest range of sizes. Consider the independent variables. What inferences might be drawn?
      
9. Determine which factors affected particle size at the sites using the following procedure:
   
      
   • Determine the average particle size category for each sample by multiplying the numerical rating of each particle size layer by its percentage within the sample.
        
   • Add these values for all particle size categories in the sample.
     Using the sample given:

        3 x .25  =    .75
        4 x .125 =    .50
        5 x .125 =    .625
        6 x .50  =   3.00
                  4.875
                (rounded off = 4.9)

        4.9 = average particle size category at the site.

        

   • Complete the data sheets by recording the average particle size category for each site.
        
   • Make a graph for each variable by plotting the numerical rating for that variable for each site on the X-axis. (See example.)
     
      
10. Discuss the students' results:
    
       
    • Is there a clear relationship between particle size category and one or more of the independent variables?
      (Graphs with points that can be connected with a fairly straight line show the most direct correlation between the two variables.) If so, what seems to be the relationship?
         
    • Do some independent variables show little or no relationship to particle size category? (Some chosen variables may actually have no influence on particle size categories. In other cases, an independent variable may have an overriding influence on particle size category. For instance, the plot in the example shows the stream as a waveless site with medium-sized particles. Here, a strong stream current might have more effect than no waves.

   
• Compare the sand samples from around the U.S. and/or world for particle size, shape, color, and composition.
     
• Look for tiny pieces of plastic with the samples. Plastic sand (called beach confetti) is a growing environmental problem worldwide.
     
• Use maps to plot the locations of samples received and discuss the possible origin of the sands in each of these places.