Matter Mysterious

Oh, dear!
What can the matter be?








No sooner had I introduced the rules for classification of matter to first graders than I pulled the rug out from under them and presented the children with samples of a substance that doesn't follow the rules. Sometimes it's awfully fun to be the trickster . . .



I set the stage by reading a portion of Bartholomew and the Oobleck, just until we got to the part where Oobleck was raining down, gooping up the entire Kingdom of Didd, including all available warning systems. What's a king (or rather, his seemingly wiser young page Bartholomew) to do? Call upon a team of Matter Experts, of course. Bartholomew rushed some Oobleck samples right over to Room 28 so that our young Matter Scientists could have a look and determine just how Oobleck should be classified. Is it a solid or is it a liquid?

The investigation was on!

What happens when you smack the surface with a spoon? What happens when you just set the spoon on the surface?






What happens when you try to stir vigorously? What if you stir gently?













Does it pour? Does it drip?
What happens when it spills?








What happens when you squeeze some in your hand?
Can you roll it into a ball?







What happens when you release your hand?


Can you slice it with a knife?



Raucously messy fun!
Mrs. C still chuckles about the time she strolled through Room 28 during an Oobleck investigation only to hear me saying (uncharacteristically urgent and shrill, as Oobleck splattered into the air and rained down onto the recently replaced carpet), "Whatever investigation you're doing, Please STOP Investigating Oobleck In That Manner!"

"Go make the oobleck tumble down
On every street, in every town!
Go make the wondrous oobleck fall! Oh, bring down oobleck on us all!"

After the children and I reviewed the evidence for classifying Oobleck as a solid and the evidence for classification as a liquid, we looked for a pattern across the situations in which Oobleck behaves like a solid. Under what conditions does Oobleck act like a solid? . . . Under pressure

A few years ago, when I discussed Oobleck with my retired-chemist father, he made a comment that I used last week to push the children's thinking further. "What would happen if we tried to pump Oobleck?" Given what we've learned about Oobleck, the children hypothesized that it wouldn't work very well in a pump. "If you use a lot of force on Oobleck, it turns into a solid. When the pump pushes on the Oobleck, I think it's going to act like a solid." (A first grader, no less!)

Of course, all talk and no action is not the way we operate in Room 28. Not satisfied with mere speculation, we had to check it out for ourselves! While the children were in Music, I transferred some Oobleck to an empty soap dispenser. The Oobleck flowed easily through the funnel, but when we tried to pump it out, it was an entirely different story. Push as we might, only a small amount of liquid that had separated out dribbled from the pump. Yep, my dad was right. "Dilatants really do a number on pumps!"

Next up was Microscopic Matter Theatre. Child actors take the role of molecules to demonstrate the states of matter. First, solid molecules stand packed close together, moving only slightly in place. Liquid molecules stand father apart, easily slipping and sliding past each other. Finally, fast-moving gas molecules bounce around the room--over here, now over there, with lots of space between each other. So the challenging question of the day is . . . what's going on with the molecules of a non-Newtonian fluid like Oobleck?

To wrap up our Oobleck investigation, I asked each group to design a spacecraft that could land on and take off from Oobleck. Their ideas were ingenious, all based in our observations of the properties of Oobleck! Their illustrations are equally wonderful. One group proposed a spaceship with break-away pogo sticks. The pogo sticks would bounce on the Oobleck, causing it to become a solid long enough for the spaceship to take off, at which point the pogo sticks would break off. Another group separately invented a ship with paddles at the bottom to hit the Oobleck. A third group's spaceship is designed with a giant spoon attached to a mechanical arm at the top of the craft, which comes down and smacks the surface of the Oobleck. By George, I think they've got it!


Several of the children have pleaded with me, "Ms. S, will you post the recipe for Oobleck on the blog so we can make some at home?" Hmmm. I'm not sure I should reveal my secrets. . . . Well, if you insist, but only because I know you love science so much!

1) Place 1 cup cornstarch in a bowl.
2) Add a drop or two of food coloring, if you wish.
3) Add about 1/2 cup water slowly, mixing the cornstarch and water with your fingers until all the powder is wet. (If you tap the surface with a finger or a spoon and it splashes, it's too wet. Add a little more cornstarch. If it doesn't pour easily, add a little more water.)
4) Get ready to investigate!

These guys took their Oobleck investigation a step further . . .

You may not be able to fill up a pool with Oobleck, but you can try heating it or freezing it! "Take chances, make mistakes, get messy!" (Ms. Frizzle, The Magic School Bus).


What We're Reading:
Bartholomew and the Oobleck by Dr. Seuss
What Is the World Made of? All About Solids, Liquids, and Gases by Kathleen Zoehfeld
KIDS DISCOVER Matter
KIDS DISCOVER Solids and Liquids


Resources:
Oobleck: What Do Scientists Do? (Grades 4-8 GEMS Teacher Guide) by Cary Sneider