How to make Oobleck

hands in oobleck Oobleck is one of those things you just have to see (and touch) to understand. Sometimes it acts like a solid, sometimes it acts like a liquid. It all depends on how much pressure you put on it. This stuff is best experimented with outside (or at your neighbors house ... ) because it can get really messy really fast.

What you need:

  • Cornstarch
  • Pitcher of water
  • Aluminum pie pans
  • Measuring cups
  • Wooden spoon
  • Newspaper for covering tables

What to do:

  1. Place 1.5cups of cornstarch in a pie pan.
  2. Add 1 cup of water and stir well.
  3. Add more water or cornstarch until you get a mixture which “tears” when you quickly scrape your finger through it and then “melts” back together again.

Squeeze it! ... Smoosh it! ... Scoop it! ... Pinch it!

What’s the Science?
Oobleck is a material that is also known as a dilatant. A dilatant is a material that gets thicker with an increase of pressure. Oobleck is a liquid until pressure is applied to it and then it solidifies. It seems to defy Newton’s Third Law of Motion that states that every action will have an equal and opposite reaction. Here is a great way to test this … take two pie pans, fill one with water and one with oobleck, take both outside and slap them with an open hand. The water will splash while the oobleck stays put on the bottom of the pan. Water is a Newtonian fluid because it obeys Newton’s Laws of Motion. Oobleck is a non-Newtonian fluid because it defies Newton’s Third Law of Motion.
 
Storage and Safety Guidelines:
Store Oobleck in an airtight container in the refrigerator for about one week of use. When you are through with it, discard in a trash container. Do not wash down the drain because it will clog it for sure!