Ooey Gooey Oobleck!

Shared by STEM Girl Day Partner: BASF Corporation

Recommended Grades: 3-5

Materials:

  • Cornstarch
  • Water
  • liquid watercolors or food coloring (optional)
  • glitter (optional)
  • bowl
  • spoon
  • ice cube trays, silicone molds, or a container to place in the freezer

Procedure:

  1. Add about 1/2 cup of cornstarch to a large bowl.
  2. Slowly add up to a 1/2 cup of water. (You usually don’t need all of the water.) Mix until you get the consistency you desire. If you add too much water, just add more cornstarch.
  3. Optional Step: Add food coloring, liquid watercolors, and/or glitter. NOTE: Food coloring has the potential to stain. Watercolors are usually washable. Just pay attention to the ingredients in the paints if your child is likely to put her hands in her mouth. (Most paints are non-toxic and shouldn’t be a problem in small amounts.)
  4. Use your hands to pick up the oobleck. Notice what happens when you mold / squeeze the material versus letting it ooze out of your hand.
  5. Make a video of your oobleck in action and share on Flipgrid.

For additional fun, freeze your Oobleck!

  1. Pour the oobleck into molds or ice trays.
  2. Place the molds in the freezer for at least a few hours.
  3. Freezing the oobleck creates a solid. As the oobleck melts, the consistency keeps changing.

How does this activity connect to STEM?  Oobleck is a non-Newtonian fluid. It doesn’t behave like a “normal” liquid. It has properties of both a solid and a liquid depending on the amount of stress applied. When stress is applied, the cornstarch and water mixture acts like a solid (your hand can’t go through; you just squish it like play dough). When constant stress is not applied, the mixture acts like a liquid.

Depending on the transfer of energy (adding or removing motion or pressure), Oobleck changes between liquid and solid. Engineers and scientists need to understand how materials behave so they know how to move them through pipes, create products with them, and use them. Ketchup behaves like Oobleck - you have to squeeze a ketchup bottle to get it to come out (you are adding pressure and transferring energy to make the ketchup flow). Paint, shaving cream, toothpaste, and even blood are other examples of non-Newtonian fluids. Can you think of others?

Watch the video below to see a brief demonstration of oobleck in action. Find additional information on freezing your oobleck at InspirationLaboratories.