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By Mom Unplugged, 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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By Mom Unplugged, October 23, 2008 11:13 am

Fall is here in the Arizona mountains. The cool morning air smells faintly of piñon smoke left over from evening fires.

The chili roaster is tumbling down at the little local grocery, producing baskets of lovely, soft charred green chilis.

Ponderosa Pines are beginning to shed some brown needles and fields are brimming with bright yellow wildflowers.

Maximilian Sunflowers line the roadways. They are tall this year which means, according to local legend, that our snow piles will be tall too.

Squirrels are getting busier as they rush off with peanuts and sunflower seeds to hide away for the winter.

The Humming Birds have left, and the Robins. Even the golfers are leaving, along with the thousands of people who spend their summers here in our mountain paradise to escape the scorching desert heat.

Peaceful silence will descend upon our town as we hardy year-round residents retreat from our porches, gardens, and decks and take to our homes in preparation for winter snow.

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By Mom Unplugged, October 8, 2008 9:06 pm

When you have a child who is reading very well at an early age, it can sometimes be difficult to find books that are challenging enough for your young reader, yet innocent enough for a child who is not ready for more mature subject matter.

I have a few suggestions. If you have not yet read Parts 1 and 2 of this series, then please head on over for some other ideas.

This week, I want to mention another lesser known set of books that we just adore. These would appeal to boys as much as to girls.

I already reviewed the first book in the series a long time ago, so I feel a bit like I am cheating. But things get buried in a blog and I MUST mention this series again because I think it is so wonderful!

This week’s suggestion is the “Noisy Village” series, by Astrid Lindgren (most commonly recognized as the author of the well-known Pippi Longstocking series).

I desperately wish there were more, but the series consists of only two chapter books: The Children of Noisy Village and Happy Times in Noisy Village.

There are also two short picture books (32 pages): Christmas in Noisy Village, and Springtime in Noisy Village (which is harder to come by).

The very charming Children of Noisy Village is actually one of the first chapter books I ever read out loud to my two oldest children. We sat on the sofa in front of the fire on a boring, snowy Sunday and all three of us laughed out loud at the funny adventures of the Noisy Village children. Much to my delight, I even found a bit of more subtle humor in the book that escaped my children. These moments kept me wanting to turn the pages as much as my children did.

In case you missed my first review, the three Swedish farm houses that comprise “Noisy Village” are inhabited by a pack of mischievous children ages 9 to 11 (as well as a baby or two). The tale is very convincingly narrated in the first person by 9 year-old Lisa.

The era of the book is never specified, but according to the “About the Author” section, Astrid Lindgren’s writing was greatly influenced by her childhood on a small Swedish farm. Since she was born in 1931, that would probably place the setting of this book sometime around 1940.

None of these simple adventures are mean or malicious, but are completely innocent and charming. I was also struck by the fact that the children never talk back, or act in a disrespectful manner to each other or their parents, as I find to be the case with many books of this genre nowadays.

If you read these books out loud, make sure you have plenty of time since you might be begged to read them cover to cover in one sitting.

For silent-reading I would place them on the same level of complexity as the Fairchild Family books by Rebecca Caudill that I reviewed last time. That is, not suitable for beginners, but perhaps not quite as advanced as the The Little House series.

More details to help you determine the suitability for your child: each of the two chapter books is about 120 pages long and is divided into 14 chapters. Typeface is medium and there are quite a few sweet line drawing illustrations (by Ilon Wikland) scattered throughout the book.

The only picture book I have seen is the Christmas one. I don’t like it as much as the chapter books. There are more illustrations, and they are in bright colors. Somehow, I prefer the subdued black and white line drawings of the originals.

Also, although the story is fun in the short Christmas book, there is a scene where one of the older boys pretends to be Santa and brings in the gifts. In my mind, this brought up the whole “is Santa real” question. Fortunately however, it seemed to escape my children and we didn’t have to address that issue. The Christmas chapter in The Children of Noisy Village was different and didn’t venture into such perilous territory.

Conclusion: I can’t recommend these chapter books enough, for both girls and boys!

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By Mom Unplugged, August 13, 2008 7:45 am

Last week I just flew our new plane from Denver to my Arizona hometown and thought I’d share a few photos of the spectacular scenery over the Rockies. Enjoy!

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By Mom Unplugged, May 23, 2008 10:13 am

Yesterday was the last day of school here. Always a sad day for me. This year however, I was distracted from my self-pity-fest by the fact that I was driving my children home on the last day of school…in a snow storm! About four inches so far. More on the way today.

On Tuesday we were sweltering in a record-setting 95 degree heat (35 Celsius). Yesterday it was 35 degrees (1.7 Celsius). A 60 degree drop in two days. Impressive!

My son’s birthday party is today. His real birthday is in about 2 weeks, but this year we are having his party early before people depart on their summer adventures. I guess we won’t be picnicking in the back yard as planned. Will the party be snowed out or will we be having snowball fights?

I told my little boy to take a good look out the window because this might be the only snowy birthday party he has in his life!