Make Oobleck


Oobleck is an easy-to-make substance that has some interesting physical properties. Oobleck is an example of a non-Newtonian fluid. Many common liquids like water and alcohol have a constant viscosity. But Oobleck can be liquid when held loosely in your hand, and can also act like a solid if it's hit more violently. The name comes from Dr. Seuss's 1949 children's book, Bartholomew and the Oobleck, which is about a king who is so bored with the weather in his kingdom that he wants something completely new to fall from the sky.[1]

Steps

Making Oobleck

  1. Place 1 cup (8 oz.) of cornstarch in a large bowl. You can spend a minute mixing it around with your hands to get comfortable with its texture. It can help to briefly whip it with a fork to get out any chunks so that it is easier to stir later.
  2. Add 4-5 drops of food coloring to 1/2 cup of water if you want a color. Though you don't need to use food coloring to make Oobleck, many people like to use it to make the Oobleck a fun color, and even more exciting to play with than white putty. If you'd like to add food coloring to the Oobleck, drop it and stir it into the water first, before you add it to the cornstarch. This helps it distribute evenly.[1]
    • Use as many drops as you want for a richer color.
  3. Stir 1/2 cup (4 oz.) of water into the cornstarch. You should always stir in half as much water as cornstarch, keeping them in the ratio of 2 cups of cornstarch for every 1 cup of water. Use either your hands or a mixing spoon to really mix the water and cornstarch as much as possible.
  4. Test the Oobleck by grabbing a handful and trying to form a ball. The hardest thing about this is getting the recipe just right. It will rarely be exactly two parts corn starch, one part water, right on the dot. Humidity, food coloring amount, and water temperature will all make subtle changes. It should feel a bit like it is melting in your hands.[2]
    • If you can't form a ball (too watery), add more cornstarch in one tablespoon at a time. Mix it and test each time.
    • If it isn't runny like a liquid when picked up, it is too thick. Add more water one tablespoon at a time.

Using Your Oobleck

  1. Play with the Oobleck. At first, just take it out with your hands and have fun kneading it, hitting it, rolling it up into a little ball, letting it drip from your hands into the bowl, and molding it into a variety of shapes. You can also--
    • Mix and match with other colors to make designs.
    • Strain and drop the oobleck through strainers, strawberry crates, and etc to watch how it flows differently than water.
  2. Experiment with the Oobleck. Once you're more comfortable with the substance, you should see what happens when you squeeze the goo hard, or when you let it sit for a minute before picking it up again. Here are some other Oobleck experiments to try:
    • Make a ball out of the Oobleck by rolling it around quickly in your palms. Then, stop applying pressure to the mixture and it will flow out of your hands.
    • Fill a pie plate with a thick layer of Oobleck and slap the surface with your open hand. You'll be surprised by how all of the liquid stays on the plate because of the force you applied.
    • Supersize the pie plate experiment by filling a large bucket or plastic bin with Oobleck and jumping up and down in it.
    • Take the Oobleck in the freezer, and try it. Try it in the heat too. Is there a difference?
  3. Clean up the Oobleck. You can use warm water to clean the Oobleck off your hands, clothes, and even off of your counter. You can rinse a bit of it out of your bowl, but make sure not to let too much of it get down the sink.
    • If you let it dry out, it turns into a powder that is easily swept, vacuumed, or wiped up.
  4. Store the Oobleck. Place the Oobleck into an airtight container or a zip-seal bag. Take it out again later and have fun playing with it. If you're done with the Oobleck for good, do not throw it down the sink, or it may clog your drain. Throw it in the trash instead.
    • You'll likely need to re-add water to your oobleck to play with it a second time.

Tips

  • Anything put into the slime (like little toy dinosaurs) can be washed easily with soap and water.
  • If you don't have cornstarch, you can always use Johnson & Johnson® baby powder.
  • Oobleck is fun to play with! Use it for birthday parties. Kids love it!
  • It is fun to try to roll your goo into a ball. If you try, it becomes solid and when you stop moving it, it will just melt back into your hand.
  • Oobleck when dried can be easily vacuumed.
  • Store in an air-tight container. Mix occasionally.
  • To dispose of it mix it with a lot of hot water to make a very loose slurry. Pour a small amount into the drain while the hot water is running.
  • If you put in food coloring: After washing your hands, you may notice a little bit of color left on your hands. Don't worry. It should go away in a day or two.
  • Making goo is great for rainy day play with the little ones. Especially when the bath is ready.
  • It's a good idea to put newspaper under your experiment in case it gets on your bench.
  • If you add food coloring, your Oobleck will be much messier and have a cool effect to the project!
  • Make sure to add water to your oobleck occasionally. This will prevent it from drying out.
  • Don't let it just sit there for a while.
  • Add a small amount of glitter to make it shimmer.
  • Make sure the container has no air in it so that it won't dry out.

Warnings

  • Oobleck isn't poisonous, but it tastes awful. Wash your hands after playing. Make sure children are supervised.
  • Don't drop on the couch, deck, or sidewalk. It's hard to get off of certain surfaces.
  • Wear old clothes, as Oobleck tends to get messy.
  • Do not pour the Oobleck down the drain or else the drain may become clogged.
  • Lay a couple newspapers on the floor so it doesn't get all over the floor or table.
  • Don't worry too much if it gets on something; it will come out with a little water.
  • Be aware that if Oobleck is left out too long, it will dry out and turn back to cornstarch. Just throw it away when you're done with it.

Things You'll Need

  • Cornstarch, sometimes called 'cornflour'
  • Water
  • Bowl
  • Food coloring (optional)
  • Air-tight container (for storage)

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Sources and Citations

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