Daisies in STEM - Oobleck
The three major states of matter are solid, liquid and gas. The rule of thumb is that solids retain their shape, liquids do not hold their shape and adopt the shape of the vessel they are in, and gases do not hold their shape and are constantly moving. But some things around us do not behave according to these rules... To explore this further, we had a scavenger hunt where the girls identified each item they found as a solid, liquid or unknown. The girls correctly identified slime and honey as liquids, however ketchup and toothpaste were harder to define.
Ketchup comes out of the bottle like liquid, but retains it's shape once it's on the plate. Toothpaste behaves the same way. Why? These are Non-Newtonian fluids. Their properties change in response to force. A really fun Non-Newtonian fluid is Oobleck, a mixture of corn starch and water in approximately 1:1 ratio. It is liquid when no force is applied, but becomes as hard as a rock when force is applied. It is really fun to touch and squeeze.
Wouldn't it be super if we could jump on a pool of Oobleck? We can! By stomping or jumping we can apply enough force to turn the Oobleck into a solid.
Without force, the Ooblek is a liquid mess...
Oobleck got its funny name from a book called Bartholomew and the Oobleck by Dr. Seuss. This is a story about a king that got bored with the regular things that come down from the sky (sun, rain, fog and snow) and had his magicians make something new that no one had ever seen before. His magicians made Oobleck, a sticky gooey mess that defies the laws of nature.
The aftermath of today's Girl Scouts meeting :)