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SCIENCE NETWORK NEWS

     We have received some great questions since the last newsletter, and we hope you will end us more. 

      It is easy for us now to go through the first issues of the Science Network News and find errors. It wasn't easy to find those errors on the days they were edited and sent to the Xerox machine. We hope that teachers, children, and other interested readers will send us corrections to the errors they have found in our newsletter. We've listed below some examples of the errors we have found.

     In No. 1, at the top of p. 4, we read these words, "When examining the sun's spectrum through a prism..." That is not the right idea. We were careless with our language. You really shouldn't examine the sun's spectrum by looking through a prism, unless you have a spectroscope or other way to screen out the sun's bright light. What you do is to hold the prism in the sunlight, so the light of the sun passes through the prism and forms a spectrum on a piece of paper, where you can examine it easily.

      A few lines further down the same page, in the quote from Jearl Wallcer's book, The Flying Circus of Physics With Answers, w e read, "the electric field of the incident sunlight oscillates the electrons in these molecules, which in turn radiate light." That is a classical physics explanation, which can't easily be reconciled with the photoelectric effect. The quantum explanation, due to Einstein, is that a photon from the sun adds its energy to an electron, which can release another photon of the same color by losing the same amount of energy, or release a photon of another color by losing a different amount. Classical physics is not dead, so the debate goes on as to which is right.

     In No. 2, p. 2, there is a diagram in which the arrows radiating from the center of the balloon are not the same length in all directions. Other arrows are uneven too. At each level, all arrows should be the same length. We are sorry about our sloppiness. We are still learning how to draw pictures on our new Macintosh computer.

     In No. 3, p. 1, we really shouldn't have said, on the last line, "but the larvae is really very busy." First of all, "larvae" is plural and "is" is singular. So the grammar is wrong. Second, as the next page says, the caterpillar or larva (singular) is dying, and thus does not sound busy. It must be the pupa that is busy, making a butterfly out of digested parts of the dead larva. Even that sounds impossible, for isn't the pupa just a shell?

     Perhaps we should find another way of saying it. We could say that the larva pupates itself into a pupa by covering itself and releasing hormones that turn on genes that absorb some old parts and grow some new ones, until it becomes a butterfly. Does that make more sense? The inside of the pupa is changing so much, is it really one thing? Are we the same person we were when we were born? Yes, we think so, although there is a lot about us that looks different. And we have it easy, because we don't pupate!

     What if we changed our number of legs, our kind of eyes, and our skin color, and even what kind of thing we call ourselves as we grow older? Would we like it better if we went into a pupa to make those changes? We could notice that a Monarch can be an egg, a caterpillar, a pupa, and a butterfly, one changing into the next. So instead of saying the pupa is changing, we should say that the Monarch is changing from one form into another. If we don't know what kind of butterfly or moth will come out, we could say that a lepidopteran insect is changing from one thing to another. Isn't it hard to get our language straight, even if we knew what was going on?

     Please be sure to ask us about what we send you if you don't think it's quite right. Sometimes, people don't like to ask questions, because the answer often makes things more complicated than they expected they would be. Other people really want to know, and can't help asking questions. Some people, like us, really like trying to find answers to questions, even though they usually get more complicated than we expected. We are learning all kinds of things by working on your questions. The world we live in is such an interesting place, we love learning more about it.

     Science Network News is published by the Center for Instructional Research and Curriculum Evaluation (CIRCE) in the College of Education at the University of Illinois. Judy Hill and Jack Easley are the editors. We welcome your questions and comments. Write to us at CIRCE, 270 Education. Building, 1310 S. Sixth Street, Champaign, IL 61820, or call (217) 333-3770. Computer (FrEdMail) addresses: JHILL@UIUCED, or JEASLEY@UIUCED.

     When I got out of the car, the rays looked the same, except the big one going straight down the windshield was missing. So that was made by the dirty windshield of the car. I took off my glasses again, and there were the rainbow colors. So could there be something in my eyes that was making them, perhaps because I am so nearsighted? Being nearsighted, everything more than a foot awe, is blurred without glasses. I have tri-focal glasses. One part of each lens is for reading books; one part is for reading computer

     One of our readers wanted to know if the auroral display would affect the ozone layer. We think this is a good question. It seems that the aurora won't affect the ozone, because they are too far apart, located in different layers of the atmosphere. The ozone layer and its worrisome holes are in the stratosphere, which is, of course, much higher than the troposphere we live in, where city air often has too much ozone for comfortable breathing in the heat of the summer. But they are considerably lower than the aurora, which is .n the highest region, the ionosphere. The stratospheric ozone layer that protects us from the sun's ultraviolet rays everyday is between 10 km (6 miles) up and 25 km (15 miles) up. There are no ozone holes reported above 25 km, and there is no aurora below about 100 km (60 miles). That doesn't mean that a magnetic storm producing aurora or the solar wind producing the magnetic storm couldn't also affect the ozone layer. I found a small book in the library by C.J.E. Schuurmans called, The Influence of Solar Flares on the Troposphere Circulation (1969). Schuurmans reports a small warming of the troposphere, a small decrease of ozone in the upper stratosphere and lower ionosphere, and a small cooling of the stratosphere about two days after each solar flare, so they seem to be due to the solar wind. While these changes don't effect us noticeably, there is an 11-year cycle in climate that may be the long-range result of solar flares.

     Another reader wanted to know if the sun spots had anything to do with the Greenhouse
Effect.. The Greenhouse Gases, like the glass windows in a greenhouse or car windows on a sunny day, trap the sun's heat. These gases trap heat mainly in the lower part of the atmosphere. In the stratosphere, we need one of them (ozone) to protect us from ultraviolet light, but the stratosphere is so thin, it doesn't trap much heat. The Greenhouse Effect is lower.

     The aurora should become visible in the vicinity of Chicago from time to time during the next two or three years when the sun spot cycle reaches a maximum, which it does about every 11 years. You may need to get out away from city lights to see it well. In Northern Canada, I once got to see the aurora a lot, and I thought it was really impressive. If you hear about another solar flare, make an aurora forecast for about 55 hours later, hope for a clear night, and go see the solar wind in action. --JE 

     "To read the vivid accounts of teaching and learning in that [Susan Isaac's] school is to rediscover the satisfaction and empowerment which derive from the adventures of minds that are freed to think." Yonemura gives an example of children asked to make a model of their garden as seen by a pilot flying overhead. "... These beginnings of aerial mapping provided the children with the roots of the discipline of geography, experienced not 'as if it were a matter of something already done, constituted, completed and finished,' but as a form of knowledge to which adults and children could contribute out of their own backgrounds." Yonemura also gives an example of her use of Isaac's model with inner-city children in New York City, saying that the model transcends race and class. The children she worked with "unenthusiastically seized opportunities to make sense of their world and to learn about their environment."

     Note: Susan Isaacs started the Malting House School for ~20 middle class children ages 2-8 in Cambridge, England in 1924 creating a "Deweyan environment that was responsive to [students] varied interests and energies." For more information about this school, see Isaacs (1966), Intellectual Growth in Young Children. [Margaret Yonemura (1987), "Reflections on Teacher Empowerment and Teacher Education", Teachers, Teaching & Teacher Education, edited by Margo Okazawa-Rey, James Anderson, and Rob Traver, Harvard Educational Review, Reprint Series No. 19, p. 277.]

 

1. To make paper you must first make a “paper mould” - a wooden frame with nylon fly screen stapled tightly to it.  You can use a second wooden frame (deckle) without the fly screen to help make your paper more even.
 
2. Take some scrap paper, remove any staples or plastic, tear it into small pieces (about 2 cm square) and soak it

3. Take a handful of the soaked paper and put it into a blender about half-full of warm water.  Blend at a moderate speed until you no longer see pieces of paper.  (If you have problems, take some paper out.)  You can add small amounts of vegetable material (like orange peels, carrot tops, or flowers) to this mixture (called “pulp”) and blend again.

Coloring the Pulp: If you want colored paper, you can add fabric dye to the pulp.  Make sure the dye is non-toxic.
 

4. Pour the mixture into a large plastic basin, half-full of warm water.  Increasing the amount of pulp will affect the thickness of the paper.

 
5. Place the deckle on top of your screen.  With both hands, dip the mould into the basin and scoop up some of the pulp.  Gently shake the mould back and forth to get an even layer of fibers on the screen.  When the water has drained through, place the mould to one side and carefully lift off the deckle, leaving the just -formed sheet on the screen.

6. To remove the paper from the screen, lay a clean kitchen cloth on a flat table, then take the screen and lay it face down on the cloth.  Soak up any extra water from the back of the screen with a sponge.  Very gently lift the screen.  The paper should remain on the cloth.

7.  To dry the paper quickly, cover it with another cloth and iron at a medium dry setting.  Once dry, pull gently on either side of the cloth to stretch it - this helps loosen the paper from the cloth.  Gently peel off the paper.

8. A CLEAN UP NOTE:  When you've finished, collect the left over pulp in a strainer.  Be careful NOT to pour pulp down the drain - it might clog it.  The strained pulp can be thrown out or kept in a plastic bag in the freezer for the next time.

The Printed Word; Heller, Jules Papermaking, New York:Watson
Printing and papermaking  Guptill, 1978.
Ontario Science Centre
770 Don Mills Road, Studley, Vance “The Art and Craft of Handmade
Don Mills Ontario.  Paper. New York: Van Nostrand
M3C 173  Reinhold, 1977.
 

Q1: What is the largest turtle in the world?
A1: The leatherback sea turtles are the largest kind of turtle. They are called leatherback, because their shell looks like leather. An average sized leatherback has a shell 6 feet long and weighs 800 pounds. People have reported seeing leatherback turtles as big as 10 to 12 feet long and weighing 1200 to 1500 pounds, but turtles that big are very rare. --JH

Q2: What is the smallest turtle in the world?
A2: We learned a lot about turtles looking for an answer to this question, but we still can't answer it well! Part of the fun of studying is learning that the world is more complicated than we expected. This is one reason we enjoy getting questions from you. Here's what I found about small turtles:
The smallest turtles in the world are probably the musk turtles and the common mud turtle. When fully grown, these turtles usually have shells three to four inches long. Musk and mud turtles can be found in the US and in Southern Canada from the east coast to as far west as Illinois in the north, and further west to Texas in the south.

     The Encyclopedia Brittanica says that there are some very small soft shell turtles that may be as little as two inches long when they are fully grown. Unfortunately, all of the soft shell turtles I could find described in turtle books were between nine inches and three feet long, when fully grown. The smallest soft shell turtles I could find were the Senegal (West Africa) soft shell turtles, which are sometimes only nine inches.
Have you ever seen a picture of a soft shell turtle? They look a lot like a pancake. A book by Dr. Peter C.H. Pritchard called Encyclopedia of Turtles has many good photographs of all different kinds of turtles. --JH

Mrs. Blasucci's Second and Third Grade class at Hoover School wanted to know:

Q3: Is there such a thing as a sea monster?
A3:People have been drawing pictures of sea monsters and telling stories about them for thousands of years, if not longer. The sea is a frightening place, and a lot of ships have mysteriously disappeared at sea, so people might say, "A sea monster got them." However, scientists try to find other explanations.
This does not mean that there are not monstrously fearful animals in the sea. The JAWS movies, about sharks, Moby Dick about a whale, and many other stories have been written about some of the huge sea animals scientists know about. Other sea animals people fear are giant clams, poisonous sea snakes, and poisonous rock fish which are camouflaged so you can't see them easily.
I once caught an octopus with arms two-foot long. I was with a friend who had some
experience with them. I'll  never forget the great struggle we had with eight arms with suckers sticking on us. As I pulled the arms off of my friend, the arms stuck to me.

      Had I been alone, in deep water, with this octopus sticking all over me, or if its arms had been twice as long, I would have called it a sea monster. As it was, we finally got it to stick many of its suckers onto the handle of a pick that we had used to remove a rock from in front of its nest.
Then we got it to go into a gallon jar, and then dumped it into a large enameled pan, where my students and we could observe it closely. It changed colors rapidly, and perhaps it was still angry at being captured, but it eventually calmed down. We offered it small rocks to build a new nest with, but it didn't. Perhaps it thought that we were monsters!

     I think that such real sea monsters are more fascinating, and more frightening if you are trying to capture one, than the ones they used to draw pictures of in the middle ages. --JE.  

Anna McBride in Mrs. Kester's class at Park school asked:
Q4. How is paper made?
A4.There are many ways to make paper. The name paper comes from the name of an Egyptian plant, papyrus. Paper was made in ancient Egypt by gluing together pieces of this plant. In ancient India, things were done a bit differently. Books were made there by tying together palm leaves. This is why the pages of books are sometimes called leaves.

There are four steps used in making paper today:

1. Gather and prepare some plant or mineral fibers.
     Most of the fibers used in making paper are from trees. First the bark removed from logs (either burned off or scraped off), and then the log is fed into a machine that cuts it into chips. The chips may then be fed directly into a machine (a disk refiner) that separates the fibers between disks of metal, or the wood chips may first be cooked in a chemical solution to remove the parts of the wood that don't make good paper. (Some of the things removed from the wood by these chemicals, like turpentine and alcohol, are also useful.) After the wood chips are cooked in these  chemicals, the resulting pulp is fed into a disk refiner to separate the fibers.

     Sometimes paper is made from other types of materials (from rags, straw or recycled paper, or from
minerals). These materials are cut into pieces and then separated into fibers in much the same way as wood fibers are.

    After the materials are made into pulp fibers, they are bleached white and then washed to remove chemicals and anything else that might have gotten into the pulp that doesn't make good paper. The pulp is left very wet. The mixture of water and pulp fibers is then fed into a machine where it is beaten and cut by knives. This will make the paper stronger. Materials to make the paper water resistant, or to dye it different colors, may be added at this point.

2. Form a paper "web" on a paper making machine, and

3. Removing the water from the paper web
     There are several different kinds of paper machines. In what is called the fourdrinier machine, the fiber and water mixture is poured on a moving belt made of finely woven wire screen. The screen shakes horizontally as it moves, and water drains out the bottom as the paper web is formed on top. Sometimes there are things like giant vacuum cleaners under the belt which suck more water out of the paper web. This web is moved by the belt to rollers which press out more water and smooth the paper. Finally, the paper is passed over very hot rollers which dry the paper.

     Other types of paper machines work in much the same way, except that they may have two wire
screens that move vertically rather than horizontally (the twin-wire former), or the wire screen may be shaped like a tube (the cylinder machine).

4. Getting the paper ready for use
After the paper leaves the paper machine and is dried, it may be run through a series of rollers called "calendars" to smooth it, or it may be coated with materials which make it smooth and shiny (like magazine paper). The paper may also be cut into smaller rolls of paper or into sheets. Then it may be sorted, counted and packaged. These are all parts of the finishing stage.

     You can make recycled paper by cutting up used pieces of paper into small strips and soaking them in water overnight. Then put the paper and water into an old blender to make paper fiber (don't use a blender that you use for food, the ink on the recycled paper is bad for you). You can also add some cut up pieces of straw or other things (glitter, if you want) to make your paper more interesting. Next you need to whir your mixture in the blender until it looks like a thin milkshake. This makes paper pulp. Then spread the pulp mixture out on a piece of window screen. After it has drained, put it between several layers of newspaper and put something heavy on top of them (a board, books, or bricks work well) so it can dry flat.

I once made recycled paper using some white and some pink paper, and adding pieces of straw. I thought that my paper was very pretty. I have asked the teacher who showed me how to make paper to give me her instruction sheet, but I haven't gotten it yet. Please write me if you would like me to send you a copy of that instruction sheet when I get it. -- JH

 

 
                                     JAWS 

Q1. Is it possible for ice (frozen water) to be more dense than liquids? i.e., Can ice sit on the bottom of a glass of a liquid?
A 1. Yes. Ice has a density of about .92 grams per cubic centimeter, and there are a lot of liquids that have a smaller density, like isopropyl (rubbing) alcohol, which in its pure form, has a density of only .80 grams per cubic centimeter. I put a small ice cube in some pure isopropyl alcohol and it sank and sat on the bottom. I diluted the alcohol with an equal amount of tap water (which should have increased the density to around .88 grams per cubic centimeter - I'm just guessing!) and the ice cube stayed about half way up until it melted.

     I thought cooking oil might work, but the ice cube I put in it floated. When I looked up the density of cooking oil I found it was also .92 grams per cubic centimeter. The ice cube, however, was filled with air bubbles, which makes it easier to float (like pumice, a rock which floats in water because of the bubbles of gas inside). So I boiled a little water for about five minutes, to get rid of the air dissolved in it. Then I poured it into some pockets in a plastic ice cube tray, in our small office refrigerator, and waited for it to freeze.

     A few days later (our freezer doesn't work well) I found half a cube of ice in one of the pockets in which I had placed boiled water in an ice tray in the ol lice retr~gerator. I took it out and put it in cooking oil and it sank. Then I took out a cube that was frozen from tap water. It floated in the oil, so I had one piece of ice at the bottom and one at the top. They stayed that way until they melted. You could see a lot more tiny air bubbles in the one that floated. You can try this experiment, too. --JE

Q2. Why is crying the reaction of sad or happy feelings?
A2. Above the outer corner of your eyes, there are tear or "lachrymal" glands which constantly produce tears (whether you're crying or not, the tears clean your eyes and keep your eyelids from scraping across your eyeballs). When you blink, the tears drain away into small holes in the inner corner of your eyes
The lachrymal glands are controlled by the parasympathetic* nervous system. This nervous system is, in turn, controlled by your brain, but it acts automatically (without a conscious decision) to increase production of tears when you're very happy or sad, causing an overflow of tears and then you cry.
But I still haven't answered your question, have I? We know how nerves and glands work together to produce tears, but we still don't know why they do things that way, or why you cry both when you are happy and when you are sad. -- JH
* The parasympathetic system is part of the "autonomic nervous system." This is the nervous system that controls automatic actions, like heart beat, blood vessel dilation, and secretion of hormones. 

Bob G. in Mrs. Sandvig's class at Prospect School asked:

Q3. Why isn't ground like quicksand?
A3. I think we can be glad that the amount of water mixed with the soil and the pressure underground that help to make "quicksand" are relatively rare. This is an exciting question for me, because it reminds me of times when I have seen earth that behaved like quicksand.

     I saw one place near Yellowstone National Park once where there had been a landslide after a heavy rainfall. The earth and rocks that had been so solid for centuries suddenly had turned into something like quicksand and sloshed downhill into a valley and part way up the other side.

     Another time, when I was working on my bird study merit badge in scouts, I followed a bird to a salt marsh, near the sea. I had been to this place before, at low tide, with no problem, but while wading through water at high tide, I stepped into quicksand and my foot started to sink. I was so glad it was underwater, for I didn't want my other foot to get caught. So I quickly lay down in the water so it would support my weight, and I easily got my foot out. Something seemed to have changed there between low and high tide. It must have to do with the amount of water in the soil.

     If there is too much water, some soils become quicksand. Of course, we've all walked in mud and left footprints in the snow. You know you'll only sink in a few inches, because the amount of liquid mixed in with the solid parts is only on the surface. Turning into quicksand is a little like mixing milk with solid ice cream to make a milk shake! The ice  cream doesn't melt, but it becomes a very thick semi-liquid.

     Of course, the amount of water isn't the only thing that keeps solid ground from turning into quicksand We can wade in streams, lakes, and oceans quite safely, and there's plenty of water in those places. In fact, the bottom of streams, lakes, and oceans is often turning into rock, because the water brings other minerals that help the bits stick together. That's how fossils get formed.

     I think the answer to this question is going to come eventually from understanding how water and the things soil is made of get fastened together or unfastened. Think of a zipper! You can see how the little hooks get together to hold tight, and how the slide can turn them on or off. But instead of just hooking magnets together in one direction, in a line, imagine things get hooked together in all directions. That's more like the way atoms stick together in ice, in concrete, and in the ground that holds us up. We can be happy it does, and that it usually even holds up huge buildings. The Leaning Tower of Pisa in Italy, however, keeps leaning over a little bit more every year, showing that the ground underneath one side is slowly swallowing the foundation from the weight of the tower pressing down. The ground there is clay, which is like quicksand but much, much slower. They are trying to do something to make the slow moving clay stop moving, before the whole tower falls over. --JE