Sir Isaac Newton was a physicist, astronomer, mathematician
and demonstrator of gravity is one of the most influential scientists of all
time! Newton defined that liquids and
fluids behave as having a constant viscosity or flow, meaning their normal
behavior only changes with a change in temperature or pressure. Between water’s
freezing point of 32⁰F (0⁰C) and the boiling point of 212⁰ F(100⁰C), water is a
standard liquid with constant viscosity. Normal liquids have a definite volume,
but no definite shape, and take the form of the container they are inside.
Liquids that don’t abide by the usual rules are called
non-Newtonian fluids. Non-Newtonian fluids change their viscosity or flow under
stress, stress is when a force is applied onto a body. Once a force such as hit
or shake is put onto this category of fluid, the stress causes it to become
thicker and act as a solid or become a runnier fluid than before. Once the
stress or force is removed and you allow the substance to sit still or move
slowly, they will return to their earlier state.
Tomato sauce is an example of a non-Newtonian fluid that becomes
runnier once stress is applied. If you want to get the sauce out of the bottle,
you hit or slap the container to force the fluid to become runny and come out
of the bottle. Oobleck is another non-Newtonian fluid, but this mixture acts as
solid once stress is applied. Oobleck is runny and watery until you apply force,
but you can hit it with a hammer and see the particles form! If you take a ball
full of oobleck in your hand and stop rolling or squeezing it, it will then
ooze out of your hand like goo! Honey, cream, toothpaste, custard, paint,
blood, melted butter and shampoo are all examples of non-Newtonian fluids!
Make your own non-Newtonian fluid! Find the recipe for Oobleck at:
https://sciencemadefun.net/downloads/oobleck-lesson-plan.pdf
