Vegetable Oil and Corn Starch
Vegetable Oil and Corn Starch

 

Code Number: 5B10.45

Demo Title: Electrorheological Liquid

Condition: Good

Principle: Electrostatic effects on fluidic polymers

Area of Study: Electricity & Magnetism

Equipment: 

Vegetable Oil and Corn Starch

Procedure:

Mix 1 part corn starch to 2 parts vegetable (Wesson) oil.  Pour the resulting mixture into another container and while pouring bring a charged PVC rod near the stream.  If the mixture is of proper consistency it will stop pouring and appear to freeze or turn solid.  Moving the rod away from the stream will allow it to continue pouring again as a normal liquid. 

References:

  • David Haase, "Electrorheological Liquids", TPT, Vol. 31, # 4, Apr. 1993, p. 218.
  • Christopher P. Jargodzki and Franklin Potter, Mad About Physics: #128, "Strange Behavior of a Mixture",  p. 48, 190
  • "An Electrostatic 'Slime'," Physics From the Junk Drawer, 3rd Edition, The Science House, North Carolina State University, p. 32.