A Lesson Plan from the Virginia State Parks'
Your Backyard Classrooms

Hot Foot

Grade Levels

4 - 12

Objectives

    Students will investigate variations in temperature and its possible effect on location of living things by:

Standards of Learning

Science:

Mathematics:

    If you have ever walked barefoot across a beach on a brilliant summer day, you already appreciate sand's ability to absorb heat. In this activity, students measure temperatures in the beach habitat to examine the effect of this abiotic factor on dune organisms.

Background

    When students visit a beach, one of the last habitats they would think of is a desert because of all the "water, water everywhere". However, in many ways, the dune and upper beach habitats are very similar to a desert. The stresses of high temperatures on the sand, intense sunlight, wind, salt spray, and dry soils demand special adaptations.

    Plants on the dunes share some of the typical desert plant adaptations. Many of the plants have reduced leaves, waxy coatings over the leaves, succulent stems and leaves, or tiny hairs or spines covering the leaf surfaces. The plants also have specialized root systems, often running deep and wide to collect water from the porous sand. These adaptations are most noticeable among the primary dune plants, such as sea rocket, Russian thistle, and sand bur. Even the shrubs of the dunes, bayberry and wax myrtle, have waxy leaves. Occasionally, prickly pear cactus and yucca plants growing in the dunes are obvious reminders of the desert habitat.

    Animals living among the dunes must also cope with the desert-like environment. One of the best ways to get away from the intense sun and heat is to dig into the sand. The ant lion digs in the sand without reinforcing the sides of its hole, which becomes a funnel. Prey then slide down the sides of the funnel into the waiting jaws of the ant lion. Other digging animals do reinforce their holes: the ghosty crab with special secretions and the wolf spider with a modified web. Blow gently across the surface of one of these holes to see the web.

    Some dune animals, like ghost crabs, have light body color which serves as camouflage and reduces absorption of heat from sun. Some have hairs, which, in addition to acting as sensory adaptations, help reflect the suns's rays. Many dune animals are crepuscular (active at dawn and dusk) or nocturnal (active at night), and thereby avoid the heat of the day.

    Anyone who has walked across the hot sand barefoot during the summer realizes the great effect the temperature might have on beach and dune inhabitants. By measuring differences in temperature along the beach and dunes and by observing plants and animals living there, students can gain a better appreciation for the environmental stresses and the special adaptations which allow these organisms to survive in their habitat.

    Beach investigation and exploration activities should NEVER be conducted on the primary dunes (first row back from the water). These dunes are both extremely fragile and vitally important to the physical (and hence biological) stability of the beach. Disturbance by humans leaves them susceptible to severe erosion. This activity may quite satisfactorily be conducted across the open beach and over the back or secondary dunes. Use only designated crossings over the primary dunes.

Materials

Per team:

Resources

Brown, V. 1983.
Investigating Nature Through Outdoor Projects. Stackpole Books, Harrisburg, PA.

Chase, V. 1987.
Living in Water - An Aquatic Science Curriculum for Grades 4-6   N.S.F. and National Aquarium in Baltimore.
Return to Procedure

Ranwell, D.S. 1972.
Ecology of Salt Marshes and Sand Dunes.   Cox & Wyman Ltd., Great Britain.

Ricciuti, E.R. 1982
The Beachwalker's Guide. Doubleday & Co., NY.

Spitsbergen, J.M. 1980.
Seacoast Life - an Ecological Guide to Natural Seashore Communities in North Carolina. Univ. of North Carolina Press, Chapel Hill.

Von Frisch, K. 1983.
Animal Architecture. Van Nostrand Reinhold, NY.

Procedure

Before the Trip:

  1. Set up experiments in the classroom to measure and compare the temperature differences which occur between air and water; between large and small bodies of water; and between dark and light surfaces exposed to sunlight. Let students become familiar with reading the thermometers. Settle on one temperature unit for recording results. In addition to temperature, other abiotic factors can be measured during this field activity if equipment such as a wind meter (anemometer) and or a soil moisture meter are available. See Living in Water    (under "Resources") for several activity ideas.

  2. Brainstorm a list of the abiotic factors affecting dune organisms in addition to temperature. Then compile a list of various adaptations which would help organisms live in a habitat with these environmental stresses. Categorize these adaptation ideas into groups such as: color, body shape and structures, senses, appendages for digging and moving, and behavior. (For younger students, the teacher might have to list some categories on the board first in order to facilitate brainstorming ideas.) Assign or have students select one category and create an imaginary dune animal which illustrates its adaptations.

  3. Through class discussion, develop a list of 5-10 predictions about temperatures at various locations and depths (e.g. on an open beach with dry sand, temperature will decrease 1oC with depth).

  4. Devise data tables for recording measurements to compare with the class predictions. (See sample.) Students rank the beach sites from highest temperature to lowest temperature based on what they predict will be the temperature differences at those sites.

  5. Divide the class into workgroups for the field trip.

At the Park:

  1. Begin temperature measurements at each site (such as lower beach, upper beach, top of secondary dune, behind dune in swale) with air temperature. Record air temperatures at different heights, such as 1 m and 1 cm above the sand, making note of any wind differences. One field group should measure water temperature as well.

  2. Begin measuring sand temperature at several depths, such as just under surface, 1 cm deep and 10 cm deep, or as needed to test predictions. Results will be more accurate if the thermometer is shaded during measurements. Make these measurements in areas of wet sand and dry sand on the lower beach, upper beach, and different locations in front of, on, and behind the secondary dunes. Carefully describe the location of each temperature measurement either quantitatively (e.g. every x meter along a transect) or qualitatively (e.g. back face of a secondary dune, in shade, no wind).

  3. Walk along the beach and among the secondary dunes, looking for animal holes, such as those of ghost crabs, wolf spiders, digger wasps and ant lions. Measure the temperature at the opening of the holes and down inside the holes. Observe any live animals found among the dunes and look for adaptations which help them survive in the dunes.

  4. Take a close look at the different types of plants growing among the dunes. Select some different kinds of dune plants to measure temperature above the plant, near the middle of the plant, or at the base of the plant, recording any temperature differences, especially if the plant's seeds are found under the plant. Make observations of adaptations which may help them survive in this dune habitat.

Follow Up

  1. Combine data from different student groups, taking average temperatures where measurements were replicated. Use bar graphs (or other appropriate quantitative graphic tools) to display results of temperatures associated with the different locations and with the different species of plants and animals.

  2. Look at results and discuss any trends:

  3. Conduct library research on the life history of any of the plants and animals observed on the dunes. Make drawings of the organisms and identify various adaptations for dune life. Present findings orally.

Where in the Park

First Landing/ Seashore State Park LF/SS Park is the only estuarine state park which offers a well-developed open beach; all others have beaches where adapted, less extensive versions of this activity are possible.
Note:
False Cape State Park		 FCSP, an ocean-front park, has excellent beaches for this kind of study. Temperature readings should be made from the lower beach up through the dunes, with the exception of the primary dunes. Animal holes will be found mostly among the dunes.

When

Time Required at the Park:

1 to 2 hours; can be done at any time of the day, but surface results will vary considerably.

Time of Year:

Any time, but evidence of animal activity will be scarce during the winter and the differences in sand temperature will not be as dramatic as during the warmer months.

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