Science as Playing Around: "Slime"

Every year my students make “slime” as part of our chemistry unit.  This “slime” is a tried and true polymer made from Elmer’s Glue and borax.  I used it from early elementary to middle school chemistry to illustrate changing properties and chemical reactions.  Just a few weeks ago, I saw a high school science fair poster comparing several different physical properties of slime variations.  This "slime" is easy to make and fun to investigate.

Materials:

• White Elmer's school glue
• Borax (found in the laundry section of your grocery store)
• Water
• Food coloring (optional, but fun)
• Plastic baggie
• Mixing container and stirrer

Steps:

1. Make a Borax solution by mixing one tablespoon of Borax in a cup of water.
2. Make a solution of water and glue, using slightly more glue than water, maybe 40% water and 60% glue.  An ounce or two of glue is a good amount to start with.
3. Add food coloring, as desired.
4. Add a couple of tablespoons of Borax to the water-glue solution and mix until the consistency changes.

Your slime is ready to play with. Store it in the baggie when you are done.

Variations:

• Try different proportions of glue, water, and borax
• Try a 4% polyvinyl alcohol solution instead of the white glue
• Add shaving cream or baby powder to the mix
• Add some glow-in-the-dark paint
• Add iron filings.  Can you get it to conduct electricity?

What did you find? What other variations can you create?

Real vs Imaginary

On March 17^th, before a session with early childhood students, the teachers mentioned St. Patrick’s Day.  In this discussion, several children mentioned leprechauns.  From the very lively discussion, the existence of leprechauns seemed implicit.  I asked, “Are leprechauns real or imaginary?”  It quickly became clear that many PK'ers believe that leprechauns are real.  Deciding to follow a critical thinking path, rather than a doctrinaire, rain-on-your-parade path, I asked what evidence they had that leprechauns were real.  I gave the example that we could demonstrate that horses were real animals because we could find a live horse and touch it.  Could we do the same for leprechauns?

Whenever a discussion like this comes up I feel it is important to proceed gently.  As a parent, I cherish my daughter’s early delight in imaginary animals and imaginary friends, as well as her continued enjoyment of science fiction and science fantasy.  As a science teacher, I do look for ways to begin to build scientific habits of mind and critical thinking.  Early childhood is not too early.  As students grow and develop, they need to be able to distinguish between what is real and what is not.  I always try to do this without being a killjoy.  I need to read some about what developmental psychologists and other child development experts say about how children acquire this ability to differentiate real from not real. 

I have had this discussion before with a different group of early childhood students and it is clear that the composition of the group and their previous experiences make a difference.  Several students in this group had been in one or more preschools where the teachers had told them about leprechauns as real beings and had helped them set leprechaun “traps”.  Several students reported that these traps had actually caught leprechauns, though no one could give a description of one.  Had this teacher or these teachers actually intended to foster the idea that leprechauns were real?  Or was this how their young minds processed a fun story and a whimsical activity?  I will revisit “real vs. imaginary” with this group.  I need to plan how to do this with sensitivity and in a way that builds their critical thinking rather than satisfying my needs to tell them how the world “really” is.

To the Moon and Back

“First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the Earth.”

President John F. Kennedy, May 25, 1961, speech to Congress.

As I sat with my students, I thought back to JFK’s historic challenge to the American people issued over fifty years ago.  We were getting ready to undertake a simulated space mission in one of the Challenger Learning Centers at a space and science center near us.  My class listened to the mission briefing about their upcoming trip to Mars, excited and a bit nervous. 

At their age, my classmates and I sat by one of the few television sets in our rural school watching the launch of Alan Shepard’s Mercury flight.  The challenge of putting a person in space was a huge technological effort, requiring advances in science, engineering, and project management, as well as human organization – an ideal STEM task.

Our students were told that they would take turns having a role on a rocket flight to Mars and on the Mar station mission control team.  Both the flight team and mission control were further divided into different teams, such as navigation, life support, communication, life science research, geological research, and medical.  Each team member worked with counterparts on Mars or on the rocket to solve realistic problems such as navigating the craft, repairing rocket life support systems, and determining what foods might be grown on Mars.  To do this, they used both their background knowledge in science and math, as well as some just-in-time learning from digital or print resources needed to complete their mission or to fix a problem.

One of the key takeaways for me was how the space simulation combined multiple levels of teaming, with individuals also making key contributions. Whether they were on the Mars station flight control or the Mars rocket, they needed to cooperate with everyone else in that room to accomplish their goal. They also needed to cooperate with their specialist team. Finally, the whole grade cooperated for the success of the overall mission. This type of simulation feels very much like the work of the future.

NGSS Developing and Using Models

Along with a group of fellow science teachers, I’ve been thinking about using models to teach science to my students.  I had always thought of models as like scale model airplanes from kits we used to assemble or as anatomical models where you can take out the heart, lungs, and liver and then stuff them back into the body cavities of a vacant looking plastic human model.  And, of course, the formal models that intrinsic to well-developed theories in science.  In fact, some sources believe that “the primary goal of science is the construction and evaluation of scientific models” (Jadrich & Bruxvoort, 2011, p. 12).

With this conception of models in mind, I hadn’t given much thought to the use of models in teaching science.  However, in learning more about the new Next Generation Science Standards (NGSS), I began to realize that models were more useful and more prevalent that I had previously thought.  NGSS presents models as representations of actual objects, systems, or processes that help us understand these phenomena.  As such, they define models to include diagrams, physical replicas, mathematical representations, analogies, and computer simulations. 

So if this was true, then the small blue plastic “flippers” in the FOSS Variables kits we used were model catapults.  True, that were really simple catapults but, as the NGSS web site reminds us, “although models do not correspond exactly to the real world, they bring certain features into focus while obscuring others” in Appendix F.  We used these “flippers” to investigate the effects of angle of the flipper, mass of the projectile, and compression of the Popsicle stick used as a springboard on the distance, as the FOSS guide suggests.

Following these science investigations, I started having my students build catapults of their own design, not only to have fun, but also to help illustrate the relationship of science and engineering.  These too were models, I realized.  The two or three stages of prototyping we did before making a final version were also models.   When we watched a NOVA video from their Secrets of Lost Empires series about a group of master builders who reconstructed a trebuchet used to lay siege to a medieval castle, I realized that too was a model.  Suddenly, models were everywhere!