The Effects of Microgravity on the Turbidity of a Non-Newtonian Fluid Mixture of Cornstarch and Water. Tevin Glover, Parker Matthews, Cedric McQueen – Co-Principal Investigators Kiristin Bullington- Teacher Facilitator W.J. Keenan High School  Richland School District One Columbia, SC

Research question Our group’s research question is, “How Does Microgravity Affect the Turbidity of a Non- Newtonian mixture of Cornstarch and Water?”

Background definitions A non-Newtonian fluid is firm when you hit it hard or fast, but when you operate in a slow motion it acts like a liquid. This makes it difficult to classify non-Newtonian fluids as solids or as fluids. Turbidity is the measure of the amount of light that can pass through a water sample. When the turbidity of a mixture is higher, the temperature is higher due to absorbed heat.

Purpose Our group wants to see how microgravity will affect the movement of starch particles in solution. In normal gravity particles in solutions move from higher to lower concentrations until they are in equilibrium.

Why does it matter? Plants store starch in their roots so our experiment could be applied to helping the growth of plants in microgravity. http://www.cnn.com/2016/01/18/world/first-space-flower-iss/

Original Experimental design The materials needed for this experiment (in each setup) are one FME II, one clamp, 6.9 mL Argo brand corn starch, and 2.3 mL distilled water. These materials are needed to test the turbidity of a mixture of corn starch and water (oobleck). These amounts came from proportions given to make larger batches of this mixture, as well as some adjustment when we experimented with placing the mixture in a sample FME.

Original procedure The materials will be loaded into a FME II and sterilized prior to shipment. We are requesting that the astronaut technician unclamp on A=0 and shake vigorously for 90 seconds. The non-Newtonian fluid will sit until day U-2, when we request that the astronaut technician re-clamp the tube in the original location. We ran a trial during experimental design to confirm mixture times and volumes. Once returned to Earth, each sample will be transferred to a test tube, where turbidity will be measured and compared. Turbidity will be measured directly with a turbidity sensor and by spectrophotometer. All materials described are available in our school laboratories.

The ground truth experiment Our control will consist of the same FME III setup for the same amount of time in regular gravity. The clamp will be removed and the sample shaken vigorously for 90 seconds in order to compare the results. The tube will be re-clamped at the same time as the one on the ISS.

Updated procedure Based on recommendations from the Step II Review Board, we have modified our experiment to a FME III enclosure in order to have three samples to compare turbidity from instead of two. After mixing and settling, the FME will be reclamped in two locations to get three samples instead of two. Volumes of materials were adjusted to mimic the concentrations of starch solutions found in plant roots.

Analyzing the results While we know the FME exposed to microgravity will be mixed more during re-entry, our hope is that a complete re- clamping will still allow us to observe how much the mixture stayed together while in microgravity. As the samples aboard the ISS are clamped the one on Earth should also be clamped simultaneously to see the difference and identify any change. Once the samples return to the earth we must analyze the turbidity. On earth there is gravity unlike when the tube, which we know from our previous trials helps to separate the cornstarch from the water over time.

Acknowledgements Partner Institutions Center for the Advancement of Science in Space (CASIS), SSEP National Partner W. J. Keenan High School Cluster

Works cited Scientific American, (2015), General format, retrieved from www.scientificamerican.com/article/oobleck-bring-science-home/ Steps required to make oobleck ©2015 FONDRIEST ENVIRONMENTAL INC. http://www.fondriest.com/environmental-measurements/equipment/measuring- water-quality/turbidity-sensors-meters-and-methods/ Shows How to measure turbidity.