Ortiz – Science: Time, Oobleck

Teacher: Ortiz (moortiz@hps.holyoke.ma.us)

Assignment:

What Is Oobleck?

Oobleck isn’t a liquid or a solid, it’s a non-Newtonian fluid. At times, it may seem like a solid or a liquid but it acts differently than a normal solid or liquid. Making oobleck is a great science experiment to show how changes in pressure can change the properties of some materials. Sort of like how temperature changes the properties of water. Cold or freezing temperatures turns water into ice. Whereas warm temperatures melts ice and turns it into a liquid.

Here’s how to see the difference you can make by applying pressure to your oobleck: Apply quick pressure with a spoon and this will increase the oobleck’s viscosity by forcing the cornstarch particles together. It will feel hard and you can even form the oobleck into a ball if you try with your hands. Release your pressure or slowly dip your spoon into the mixture and it will act like it’s more like water. By moving slowly, the cornstarch particles have time to move out of the way.

If you want to pair this activity with a book, you can read the Dr Seuss book, Bartholomew and the Oobleck.

Oobleck Ingredients

Oobleck Ingredients

Here’s what you’ll need to make this oobleck recipe:

How to Make Oobleck: Step-by-Step Instructions

Here are the step-by-step instructions for how to make oobleck: 

1. Mix 2 cups of cornstarch to 1 cup of water into a bowl. Mix the cornstarch and water until your oobleck is formed.

Tip: If you would like to color your oobleck, add your food coloring to your water and then mix with the cornstarch.

Mix cornstarch and water

2. If you find the mixture is a little too watery and not forming into a solid when you pull the oobleck out of your bowl then add more cornstarch. If you find the mixture is not dripping like a liquid, add a little more water. Just keep experimenting until you get the consistency of oobleck.

Activity Suggestions: 

  • Take a potato masher or spoon and hit the top of the oobleck quickly. You’ll notice the spoon or utensil will bounce off, giving the appearance that the oobleck is a solid. As mentioned above, this is because the pressure forces the cornstarch particles together increasing the oobleck’s viscosity. Then move slowly into the oobleck with your spoon and this will allow the particles time to move out of the way which will let you dip it into the oobleck.

Oobleck Experiment

 

  • Pick up the oobleck with your hands and form a ball. Then let go of the ball and watch it melt into your hands like magic!

Cornstarch and Water

(https://www.thebestideasforkids.com/how-to-make-oobleck/)

 

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