Kitchen – Non-Newtonian Fluid; aka “Oobleck!! – (Weekly Unplugged Project)

By , November 10, 2008 10:00 pm

Today, along with a visiting friend, we finally got to do this week’s kitchen Unplugged Project.  We used cornstarch, a common kitchen ingredient, to create a non-Newtonian fluid.  The other name for such a mixture is Oobleck, from the Dr. Seuss book, Bartholomew and the Oobleck.

It was SO COOL!!  The kids and I found it fascinating!  I was so enthralled that I felt that the mess (and there WAS mess), was actually very worthwhile.

I set out four small mixing bowls and spoons, one for each child.  I also set out water, cornstarch, and measuring cups.

The kids each put about one cup of cornstarch into their bowl.

I had them add water just a bit at a time,

and stir until we got the “right” consistency.

It was probably close to about a half to two thirds of a cup of water, but the “right” consistency was quite obvious.  When the mixture starts to feel hard to stir although it looks like liquid on the top, then it is probably about ready.

Test it by dipping your hand in, lifting out some fluid, and squeezing it into a ball.  It should feel like a hard, dry ball in your hand but when you open your fingers, it will turn back into a liquid and run back into the bowl.

Here is a fleeting picture of it as a solid:

Adjust your mixture by adding a bit of water if too dry, or a bit of cornstarch if too wet.  You’ll know you have it right when the oohs and aahs begin!

This was so much fun to play with and was a very weird sensation that is quite hard to describe.  The children (including my 2 year-old) and I played for maybe an hour:  squeezing, stirring, punching, and even hammering!

My favorite trick: If you roll it between your two palms as if you are making a ball with clay, it makes a nice solid ball, but as soon as you release the pressure, it all runs away!

Also, put a finger gently into it and it will slowly and strangely be sucked under as if in quicksand.  Jab the finger in quickly, and it will hit a hard surface.

The Science:

As I understand it, when you squeeze the mixture, or compress it quickly in some way (hammer, punching, etc.), the molecules compress and become a solid.  When the pressure is released, the molecules spread out again and the mixture becomes a liquid.  As my oldest daughter said:  “Oooo!  I can feel it changing from a solid to a liquid!”

Here are two good explanations of what a non-Newtonian fluid is:

“Oobleck is often referred to as a ‘non-Newtonian’ substance because it does not behave as Newton’s Third Law of Motion states; for every action, there is an equal and opposite reaction. Applying this principle, you would expect Oobleck to ‘splash’ when you ‘smack’ it with your hand. (Smacking is the action, splashing is the reaction.) However, when you try this out Oobleck does not splash, in fact, it becomes a solid substance for a few moments.”

(from Oobleck – a Non-Newtonian Fluid)

or

“Isaac Newton defined normal liquids as having consistent flow behavior affected only by temperature or pressure; so fluids that change their resistance to flow (viscosity) under stress are not ‘normal’. Some of these fluids get runnier when stress is applied, like paint, toothpaste and slug mucus. Some get thicker, like quicksand and Oobleck.”

(from Science in the City – Bullet Proof Goo)

As to why it behaves this way, it seems that this is actually a matter of some controversy, but here are some links that are more knowledgeable than I:

Oobleck -  a Non-Newtonian Fluid

More About Liquids: Thick and Thin

Fun:

You can actually walk on this stuff!  My son wanted to try it after seeing this You Tube video.

(There are a few other walking on cornstarch videos out there if you are really into this!)

Tips:

1) I STRONGLY recommend that you either do this outside in an area that you can just hose off afterwards, or use a vinyl tablecloth that you can remove and hose off afterwards.  Why didn’t I use mine?

2) Be sure to add the water a bit at a time, it is easy to overdo it.

3) If you do forget the tablecloth like I did, you will find that non-Newtonian fluids can be difficult to clean off a table.  When you try wiping what looks like liquid, it turns into a solid and sticks.

When you stop scrubbing it returns to a liquid state!  After a bit of frustration I used my science brain and poured water on the table.  I was able to wipe the now runny cornstarch liquid into a trash can.

++++++++

Although I suggested it humorously yesterday, I have actually had several votes for an Unplugged Project theme next week involving “sort, trash, junk, donate.”  Well, why not??

As Captain Jean-Luc Picard would have said (see, I haven’t always been without a TV!):  “Make it so.”

Let’s call next week’s theme:

Sort-Junk-Donate

Remember, the theme can be loosely interpreted if you don’t feel like cleaning your house this week.  Just be creative and have fun!

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16 Responses to “Kitchen – Non-Newtonian Fluid; aka “Oobleck!! – (Weekly Unplugged Project)”

  1. [...] Kitchen – Non-Newtonian Fluid; aka “Oobleck!! – (Weekly Unplugged Project) [...]

  2. Wow, you learn something every day! We just call this goo!
    http://whatsheupto.blogspot.com/2008/02/goo-day.html

    onemothersloves last blog post..Thanksgiving Songs – Know Any?

    [Reply]

  3. shawna says:

    Oh man I LOVE oobleck! Isn’t it amazing? My cousins went to a science fair at UW this summer and they had a whole tub of blue oobleck that you could practice walking on, and the trick was to go as heavily as possible, quite the opposite of what you would think. Not to tread lightly as if on egg shells, but to jump your way across. I would have loved to seen that!

    shawnas last blog post..What’s in a name?

    [Reply]

  4. Dayna says:

    ohhh so cool. I saw these clips on you tube and had wanted to give it a go…but I think you just encouraged me to try this when we can do it outside with a hose! Good idea :)

    Daynas last blog post..Unplugged Challenge – Kitchen

    [Reply]

  5. Heather says:

    Great project. My boys love doing this. Even my big guy (DH) loves it. Lol

    Heathers last blog post..Unplug your kids…Kitchen

    [Reply]

  6. That looks like a lot of fun, but I agree with the person who suggested doing it outside with a hose handy.
    The new theme is perfect for us since the University Family Housing authorities are coming to inspect all the apartments this week and our apartment is less than perfect (a vast understatement).

    [Reply]

  7. Looks like lots of fun as usual! I agree that this looks like an outside activity! As I was reading through, I noticed you were inside and was thinking to myself… how is she going to clean this one up? HAHA! :) Thanks for another great idea!

    Also…. You’ve been awarded an award! :)

    http://boysrulemylife.blogspot.com/2008/09/beary-sweet-blog-award.html

    Becky@BoysRuleMyLifes last blog post..Fuzzy Wuzzy was a Will

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  8. Cindy says:

    Remember – NEVER, EVER pour this stuff down your sink. Unless you are married to a plumber! ;)
    Dump it outside somewhere or in the trash.

    Cindys last blog post..King of Fall

    [Reply]

  9. janie says:

    i usually let my daughter play with this outside because of the potential mess. but if it’s not humid in your house, you can let the water evaporate and then just wipe up the corn starch. a humid house in the south isn’t good for this, but if you are up north where your house tends to be dry in the winter, it cleans up pretty easily. i have also taken a plastic scraper that i use to scrape dough off the counters and scrape the goo off the table. the flat edge works better than the soft edge of a cloth.

    [Reply]

  10. Anna says:

    I’ve had a few boxes of cornstarch sitting on my shelf for a couple months just to try doing this. Thanks for the reminder!

    Annas last blog post..Grey or Gray

    [Reply]

  11. Jenny says:

    Oooo, what fun! CJ would have loved this project! I think we did this last year sometime, and she ended up standing in the 13×9 pan we used to mix. And it WAS a mess!

    Jennys last blog post..At Last…Books!

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  12. [...] Kitchen – Non-Newtonian Fluid; aka “Oobleck!! – (Weekly Unplugged Project) [...]

  13. John says:

    I love doing science experiments and projects with my son. Slime, Glurch, Gluep, and Oobleck are classics! I have since moved on to other cool neat experiments since they enjoyed those so much. I found a cool place for free experiments. I will post it below for anyone whos interested.

    http://weirdsciencekids.com/FunExperiments.html

    [Reply]

  14. Lindsey says:

    The word for non-newtonian is Thixotropic. Wow, it’s been a good three years since I actually used anything I learned during my physics degree!

    Just found this blog and think it’s wonderful!

    P.S. As well as being a physics geek I used to give circus skills lessons and one of the routines we did was to juggle balls of cornstarch or custard powder fluid. Very fun!

    Lindseys last blog post..Preschooler sewing kit

    [Reply]

  15. [...] soft and we made moth feeders out of soft cotton balls.  Another time the theme was kitchen and we made Oobleck because it was made with cornstarch which is a substance you find in the kitchen, right?  If you [...]

  16. [...] once soft and we made moth feeders out of soft cotton balls. Another time the theme was kitchen and we made Oobleck because it was made with cornstarch which is a substance you find in the kitchen, right? If you [...]

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