Green Slime made from glue and borax and food coloring.
After enduring a challenging quiz about solutions and colligative properties students in Chemistry 201 were able to spend some time learning about viscosity and about non-newtonian fluids. We explored the properties of oobleck and slime. Oobleck, named after a story by Dr. Seuss: Bartholomew and the Oobleck is made from corn starch and water in a ratio of approximately 1:1.5 depending on the consistancy that is desired. Slime is a polymer made from glue (polyvinyl acetate) and borax and may be dyed with food coloring.
Monica found a way to record the formation of the oobleck by using her cell phone to record images as she stirred the solution. This is a reminder to all of us that there are creative ways to document observations in the laboratory.
Cell phones may be used to document change.
I believe we will be seeing more and more digital devices used in the laboratory in this way.
What is this stuff?
Students explored the physical property of viscosity – the resistance of a substance to flow and learned about sheer thickening and sheer thining (catsup) fluids. For some students this was a very novel experience. But there truly is no better way to learn about viscosity than to touch and hold these substances. Students also examined corn syrup at three different temperatures: cold (in an ice bath), room temperature and warm (on a hot plate set to low). They learned that temperature does affect viscosity.
Stretched Purple Slime
Students have been learning about intermolecular forces, forces of adhesion and cohesion. We’ve discussed why water moves up a thin tube of glass (capillary action), why water beads up on wax but oil spreads out on water, and why temperature affects the states of matter. But there is no substitute for direct experience with goo!
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