Non-Newtonian! - An experiment on the behaviours and viscosity changes in non-Newtonian fluids
Justin Luke, Wesley Yue
Shaughnessy Elementary
Floor Location : J 084 P

Non-Newtonian! is an experiment testing which non-Newtonian fluid has the most change in viscosity. rnrnWe first heard of non-Newtonian fluids in a elementary physics book and was facinated by their unique properties. Non-Newtonian fluids are fluids that do not have the same properties as Newtonian fluids, which are fluids that follow Isaac Newton's law for fluid viscosity. Newton thought that the viscosity of fluids would not change unless the temperature changes. But today, we know that besides temperature, another factor affects the viscosity of certain fluids, which are non-Newtonian fluids. This factor is force.rnrnWith further research, we found that the change in viscosity of non-Newtonian fluids can be an increase or a decrease, depending on which type of non-Newtonian fluid. Shear-thickening fluids increases in viscosity and shear-thinning fluids decreases in viscosity with force.rnrnWe were interested to find out which non-Newtonian fluid would have the most non-Newtonian properties (the most viscosity change). We wished to test oobleck (a mixture of and cornstarch) and hand soap, which are shear-thickening fluids, and toothpaste and ketchup, which are shear-thinning fluids.rnrnBecause we do not have special equipment like viscometers to measure the viscosity of fluids, we developed our own method to find the viscosity of a fluid. We put each fluid in seperate cups and poured each out into a bowl at seperate times and timed how long it took for each fluid to come out of the cup completely. The time it takes to come out will be our measurement of viscosity. We repeated this procedure, but mixing each fluid with a beater first, which is applying force, immediately before pouring the fluid out again and timing. We then found the difference in viscosity for each fluid by comparing the time it took for each fluid to come out of the cup before and after we applied force to the fluids.rnrnIn our hypothesis, we thought that oobleck would have the greatest change in viscosity, as it changes from a liquid like state to almost a solid when you apply force to it. Our experiment found that toothpaste had a much greater change in viscosity than oobleck. The cause of this may be that oobleck returned to its original liquid-like viscosity while we were pouring it out after we beated it, which affected our results.rnrnWe were hoping that the results from our experiment will be taken into consideration by rheologists. With our comparison of different fluids, rheologists can look at the particles in the different fluids (the cause of the non-Newtonian behaviour) and see which particles are more effective than others so they can apply them in products that use non-Newtonian fluids.rnAs we were researching non-Newtonian fluids, we found that information was difficult to find and understand. With this science fair, we can show our community the unique properties of non-Newtonian fluids in a more simple way so everyone can learn about this interesting fluid in our world.