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Homemade slime is a super-fun and educational activity for when the kiddos are bored at home, but there’s another substance that’ll likely blow their minds even more — oobleck. What makes the concoction so interesting is that it quickly changes from liquid to solid and back again with only a little manipulation from the user. This phenomenon occurs because oobleck is what’s known as a non-Newtonian liquid.
Named for the scientist who first described them, Sir Isaac Newton, Newtonian liquids always maintain the same level of thickness and stickiness (also known as viscosity) no matter how much pressure is applied, provided the temperature remains constant. Examples of Newtonian liquids include water, gasoline and alcohol.
Non-Newtonian liquids, however, don’t abide by those same rules. When pressure is applied to a non-Newtonian fluid in its liquid state, the viscosity changes, but for this alteration to maintain the pressure has to continue. This is why oobleck can turn from a soupy mixture one second into a solid once it’s squeezed and manipulated, and then go back to liquid practically instantly once the pressure is off.
These scientific principles are both important to grasp and fun to see in action. Take a shot at the following recipe, adapted from one published by the world-class research facility Jefferson Lab.
Recipe for Oobleck Using Borax*
For the borax mixture:
1 tablespoon (15 ml) borax
1 cup (250 ml) of warm water
For the glue mixture:
4 fluid ounces (125 ml) Elmer’s glue (school glue or glue-all)
4 fluid ounces (125 ml) of water
1 small, zipper-lock plastic bag
Green food coloring (or any other color)
2 bowls
Measuring spoons
Measuring cup
Mixing spoon
Procedure:
1. In the first bowl, mix the borax and warm water. The borax needs to dissolve completely.
2. In the other bowl, mix the Elmer’s glue and water.
3. Measure 2 teaspoons (10 ml) of borax solution and pour into the plastic bag.
4. Add a couple drops of food coloring to the bag.
5. Add 2 tablespoons (30 ml) of the glue mixture to the bag.
6. Securely close the bag and mix it together by squishing the bag around for about two minutes.
Note: If you want a bigger batch of oobleck, start by adding a few drops of food coloring (and any glitter or beads you wish) to the glue mixture and stir.
Add about half of the borax mixture to the glue mixture and mix.
Keep adding more of the borax mixture until the oobleck comes together. Then start squishing it with your hands.
7. Store oobleck in a plastic bag when not in use.
Recipe for Oobleck Using Cornstarch*
1.5 cups cornstarch
1 cup water
Green food coloring (or any other color)
Measuring cup
Bowl
Mixing spoon
Procedure:
1. Add a few drops of food coloring to the water and stir.
2. Pour the water slowly into the cornstarch and start mixing. If the mixture feels too runny, add more cornstarch.
3. Once you’ve got the right consistency, use your hands to pick it up and start squeezing! Store in a plastic bag when not in use.
*Never eat or drink oobleck. Children should only make oobleck when supervised by an adult.
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Fun Activities With Oobleck
Squeeze oobleck into a ball and notice it becomes hard. But open your hand over a bowl and let the oobleck slide out and it turns back into a liquid!
Place oobleck in a plastic container and start shaking or bump against a table.
Push your hand in the mixture and notice that it goes through easily. Then try to punch it and feel the resistance.
If you drop a light rubber ball from a height into the bowl, you’ll see it bounce off the oobleck mixture.
Live Science also suggests you place the mixture on top of an old speaker and watch it “dance.”
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