Spotted Salamander’s Life Cycle

Here in New Hampshire, the shifting face of the spring landscape, its textures and colors, the fluctuating temperatures, and the alternation of sunny clear skies with snow, rain, or sleety conditions all combine to prompt our curiosity about changing states of matter. Particularly puzzling is that wizard molecule – Water, a.k.a. H2O.  As the surface beneath our feet shifts from glacier to flood to mud to rock hardness and back again – all in the course of a couple weeks, we’re piqued to study physical science – as are the youngsters.

And such investigations can be enhanced by considering the amazing vertebrates who manage to survive these rapid changes without the benefit of insulated houses with asphalt roofs, energy grids, or wood stoves.  From freshwater fish to frogs to salamanders, these neighbors of ours should (and can be) included in the learning.  Indeed, doesn’t the importance of water’s density in its solid versus liquid state acquire much more meaning when considered in terms of the fate of the perch – when we imagine this golden, leaf-shaped fellow drifting slowly around under the ice in the oxygen-depleted depths of the nearby pond.  While a classroom demonstration of ice cubes floating in a drinking glass will connect youngsters’ water knowledge to their indoor experiences, I encourage you to use their studies of physical science to help them forge links to their outdoor surroundings and their non-human compatriots as well.

With this in mind, here’s a salamander project that I usually share with my first grade or kindergarten students during early spring.  It can be used to highlight the creatures of vernal pools and the importance of these temporary wetlands to the ecosystems of the Northeastern forestlands.  Alternately,  it can amplify a study of  some of the life cycles that are spinning so quickly at this time of the year.  That said, in today’s formulation, we are using it principally for physical science learning.  As such, it illustrates water’s antipathy towards oil, in other words: that water and oil don’t mix.  As this is a pivotal phenomenon leading to the evolution of the cell membrane, this is a good bit of knowledge to acquire!  And even young students can begin learning about this basic fact while creating a charming salamander life cycle to take home and share.

Here’s the black and white PDF:  Salamander 2018

Salamander 2018 EB

And here it is transformed with crayon, oil pastels, watercolor washes and human effort!

IMG_6462EB           IMG_6460EB

The Procedure in Detail:

To start, you can catch students interest by showing them a small, prettily-shaped glass bottle containing a layer of water that’s been colored with water-soluble food coloring and a second layer of safflower (or some other vegetable) oil.  I ask the youngsters to notice the two distinct layers that have formed and then to shake the container vigorously – but with care.  Then I encourage them to watch patiently so that they can see both the temporary mixing of the colors and then the gradual reappearance of the two layers of oil and water as the little molecules of each redistribute themselves according to density.  Next we discuss what they’ve seen.  If I’m working with older students especially,  we learn a little more about “density” and “emulsions.”  In any case, I mention the well-established fact that water and oil (and the related fats) tend to repel each other.  Then we put this specific knowledge into practice with the salamander project – which also  teaches them the art technique known as ‘watercolor resist.’

 

Materials List:

            Prang Water Colors

            Water

            Crayola Watercolor Markers

            Beeswax Crayons (such as those produced by Stockmar)

            Oil Pastels such as Craypas by Sakura

            A little cooking oil

            A small amount of butter

            Pencil

            Applicators such as a brush or knife or the handle of a brush

            Smooth White watercolor paper or 50# plus cover stock

            A well-dissolved transparent watercolor wash in a container

            Copies of the Spotted Salamander page

            Books or laminated Photographs of Spotted Salamanders

            Paint shirts or aprons – An option if the students need them

            A Bluish Watercolor Wash

(To make the watercolor wash, simply pop out the blue oval pan from one of Prang’s excellent watercolor sets. Put the entire oval in a shallow container of water.  The color will quickly begin to dissolve, thereby creating a very useful watercolor wash.  When the water is dark enough, remove the oval, let it air dry, and put it back in the tray.  By the way, the excess wash can be allowed to evaporate in the container for later rehydration and use as a wash in other projects.)

As a preliminary class demonstration, on a sheet of heavy white paper, apply (or let several volunteers apply) a series or stack of labeled squares made from watercolor marker lines, dabs of cooking oil, wax from a dragged candle, a streak of butter, a mark from an ordinary or beeswax crayon, and a thick application of oil pastel. Explain how oils, fats, and waxes are all closely related organic molecules.  Next brush lightly over the different patches with the watercolor wash and watch as the various substances repel the water – or not.  Sometimes the color patches will cause the  blue wash to bead up, and sometimes, it will retreat away from the marks entirely.  In contrast, the wash should clearly blend with the watercolor marker square.  Explain that the oil, wax, and fat molecules do not mix well with the water molecules of the watercolor wash due in part to the polarity of the water, i. e. its molecules’ partial electrical charge (something they can learn more about in the future).

Next, help make children’s understanding of fats’ / oils’ resistance to water even more memorable by inviting them to transform the image of the spotted salamander and its life cycle with crayons and yellow oil pastels (thickly applied for the spots).  Hopefully, you’ve already discussed these creatures earlier so now you’ll only need to show some photographs or books to refresh children’s memories about these creatures and their lives.  Once the students have colored the salamanders, the larvae, and the eggs in the egg mass (using white oil pastels or crayons for these – and black or brown for the little embryos) have them move to another table that is supplied with the prepared mixtures of watercolor wash in containers, large brushes, and perhaps, paint shirts.  Show the youngsters how they can gently sweep the wash across the colored page.  If they’ve applied the Craypas and wax crayons heavily, they’ll probably notice how the oily coloring materials dramatically repel the wash.  Now the colored areas will stand out vividly in contrast to their watery surroundings.   When students have finished their initial salamander sheet, invite them to create (on heavy paper) their own freehand drawings of salamanders and egg masses – or underwater environments in general.  Best results are usually obtained by first drawing in pencil (although this is not essential) and then using plenty of oil pastels and crayons before finally applying – with a light, gentle swoosh, not repeated scrubbing –  a generous amount of the blue watercolor wash.

(For older students, I add green paint to the blue while mentioning that this represents the important cyanobacteria and single-celled photosynthetic Protists in the water.  I explain to the children that these abundant microscopic beings are important food and oxygen producers for the larval salamanders and tadpoles (larval frogs) in these ecosystems.  Additionally, to a particularly attentive class I might also mention that there is an intriguing symbiotic partnership  between one species of these minute photosynthesizing creatures and the embryos encased in the gelatinous egg masses .  Most authorities suggest that these single-celled green protists are benefitting from the nitrogenous wastes excreted by the developing spotted salamanders. In turn, the protists are supplying the embryos with extra oxygen and sugars.  There’s even research showing that some of these organisms are actually living within the cells of the salamanders!