Lesson Goals:
| Big Idea: When two or more different substances are mixed, a new substance with different properties may be formed. |
TEACHERS: Click here for a fun way to present this lesson!
Reminder to get parent permission 24 hours prior to using these ingredients in the classroom (as per district policy).
STEM EXTENSION: For a stronger engineering connection provide craft materials such as craft sticks, cardstock cups, and plates and challenge kids to make a probe capable of landing on the surface of Planet Whatzit. Fill a large aluminum pan with "Whatzit" so the group can test their probes by dropping them into the pan from a fixed height.
Warnings
Questions about Whatzit that need to be answered:
Possible "What happens when..." or "What happens when you try to..." questions to get you started:
Reminder to get parent permission 24 hours prior to using these ingredients in the classroom (as per district policy).
STEM EXTENSION: For a stronger engineering connection provide craft materials such as craft sticks, cardstock cups, and plates and challenge kids to make a probe capable of landing on the surface of Planet Whatzit. Fill a large aluminum pan with "Whatzit" so the group can test their probes by dropping them into the pan from a fixed height.
Warnings
- Don't drop Whatzit on a couch, deck, or sidewalk. It's hard to get off.
- Whatzit isn't poisonous, but it tastes awful. Wash your hands after playing.
- Wear old clothes, as Whatzit tends to get messy.
- Don't worry too much if it gets on something; it will come out with a little water.
- Lay a couple newspapers on the floor so it doesn't get all over the floor or table.
- Whatzit may solidify if it's not kept wet. If it hardens, just throw it away.
- If Whatzit is left out too long, it will dry out and turn back to cornstarch.
Questions about Whatzit that need to be answered:
- What properties does Whatzit have?
- Ask questions as you experiment with your Whatzit. Most should start with "What happens when..." or "What happens when you try to..."
Possible "What happens when..." or "What happens when you try to..." questions to get you started:
- What happens when you slowly push on the Whatzit?
- What happens when you quickly push on the Whatzit?
- What happens when you let the Whatzit hang from your hands?
- What happens when you put Whatzit into the freezer overnight?
- What happens when you try to pour Whatzit?
- What happens when you try to float things on Whatzit?
- What happens when you try to form the Whatzit into a ball?
- What happens when you try to tear Whatzit into pieces?
Videos & More after the break (but don't peek until after the lab)...
After the Lab...
A Non-Newtonian fluid is a substance whose viscosity changes depending on the force applied to it. A mixture of
cornstarch and water, commonly called Oobleck, is an example of a Non-Newtonian fluid. Oobleck is made from a
suspension of solid particles packed together and almost touching each other. These particles are floating in water and are just able to slip past one another other. When Oobleck is gently stirred or moved the suspended particles are able to slowly slip past each other allowing the mixture to act like a flowing liquid. However, if you suddenly poke the mixture and apply a force, the particles jam into one another and stick together, making the mixture act as a solid.
NEWTONIAN LIQUIDS SUCH AS WATER, VINEGAR AND MOST OILS FLOW AT THE SAME RATE REGARDLESS OF THE FORCE THAT IS APPLIED TO THEM. Non-Newtonian fluids flow at different rates depending on how much force is being applied to them. Oobleck’s ability to flow slows down when a force is applied to it. Squeeze it hard enough and it will turn from a liquid to a solid. Let it go and it turns instantly back into a liquid.
Here's a kid-friendly website with a great explanation: science-u.org/oobleck.html
Handout from the website (with answer key): science-u.org/assets/pdf/science-u-oobleck.pdf
One additional set of teacher-led experiments could include:
cornstarch and water, commonly called Oobleck, is an example of a Non-Newtonian fluid. Oobleck is made from a
suspension of solid particles packed together and almost touching each other. These particles are floating in water and are just able to slip past one another other. When Oobleck is gently stirred or moved the suspended particles are able to slowly slip past each other allowing the mixture to act like a flowing liquid. However, if you suddenly poke the mixture and apply a force, the particles jam into one another and stick together, making the mixture act as a solid.
NEWTONIAN LIQUIDS SUCH AS WATER, VINEGAR AND MOST OILS FLOW AT THE SAME RATE REGARDLESS OF THE FORCE THAT IS APPLIED TO THEM. Non-Newtonian fluids flow at different rates depending on how much force is being applied to them. Oobleck’s ability to flow slows down when a force is applied to it. Squeeze it hard enough and it will turn from a liquid to a solid. Let it go and it turns instantly back into a liquid.
Here's a kid-friendly website with a great explanation: science-u.org/oobleck.html
Handout from the website (with answer key): science-u.org/assets/pdf/science-u-oobleck.pdf
One additional set of teacher-led experiments could include:
- Putting a batch of Oobleck into the microwave for 5 seconds & predicting how it might be affected by the heat.
- Putting a batch of Oobleck into the freezer for 15 minutes & predicting how it might be affected by the cold.
If you want to continue the fun at home (with an adult):
Directions for making Oobleck at home. | Oobleck's not all that great - just ask the king! |