corn syrup viscosity experiments

Base: this teaching assignment is modified from one by Ben Edwards that I found on the SERC website.   The original description and files are here

Modification reasoning: the original assignment was designed for a sophomore / junior level petrology class and I wanted to use the activity with my Jterm class, which are mainly non-majors

What did I change?
  • I removed the discussion of types of fluids (Bingham, pseudo-plastic, etc.)
  • since I only have 6 students in the class, I had them do the entire activity as a single entity instead of dividing them up into groups
  • I re-arranged things into chart format because I thought they were easier to read / understand what data needed to be recorded
  • I did not require the students measure the angle between the tilted board & the table-top because I decided not to include the calculations
  • I did not ask some of the analysis questions on paper, but instead discussed them once we had finished with the activity
  • I did not include Part 4: Viscosity and Volcanic Hazards or Part 5: Magma Viscosity and Density as a Function of Magma Chemistry
  • clear corn syrup (48 oz for all four parts of the experiment - comes usually in 16 oz bottles, so 3) -- my grocery store had it in the breakfast aisle
  • a board to tilt (we propped ours up on a spare box that was lying around; original has a wooden "ski jump" like object to tilt it) -- I used a large wooden cutting board
  • wax paper (other suggestion was shelf paper) to go over the tilted board
  • a rubber / plastic sheet to put down underneath the experiment set-up -- we used an old plastic shower curtain -- to keep the corn syrup from going everywhere; we ended up washing off the curtain half-way through the experiment
  • plastic cups / beakers to pour the corn syrup into (divided into 9 parts)
  • straws
  • whisk
  • pyrex measuring cup (used to hold corn syrup while whisking in bubbles & to heat the "hot" experiment in the microwave as well as add water)
  • sand / rice / cake sprinkles -- we used couscous, because I had some in my kitchen
  • stop watch (modern cell phones usually work fine in the stop watch mode)
  • rulers
  • paper towels / sponge for clean-up, though the plastic shower curtain kept this to a minimum
  • some way to cool off the "cold" experiment -- its winter in St. Peter, so we just put the cup of corn syrup outside in the snow while running the other experiments first
  • worked absolutely wonderfully
  • clear distinction in speeds, shape of the flow, and how easy / hard it was to blow bubbles for the nine different experiments
  • two weeks later, the students still remember running the experiments and which flows went faster vs. slower
Pictures of the set-up & experiments are up on my blog here.
Elli Goeke,
Jan 27, 2011, 8:07 AM