Shirley Hatcher (Williams School)
put us to work making our own butter. (handout) We each got our own jar (baby food jar or bottle) with a couple of marbles in it, and we half filled the jar with Dean's Heavy Whipping Cream. With the jar tightly capped, we vigorously shook it, following Shirley's lead. Before long it got thick - it became "whipped cream" - and Shirley pointed out that the sound of the marbles "clicking" against the jar became much harder to hear. Pat Riley asked, "What is going on?" Is there a chemical change?..physical change? Discussion led to the idea that the change was physical, breaking up the fat in the cream into smaller particles, eventually creating a colloidal suspension - butter! We could see the butter "lump" formed at the bottom of the jar, and liquid above the lump. (Curds & whey?!) Other colloids are: jello, ice cream, homogenized milk, cheese. Very interesting!
Erma Lee (Williams School)
started with several identical jars (nearly pint size), one filled with marbles. (handout) She filled it with water, and asked us to guess how much of the space was filled with marbles, and how much with water? Guesses ranged from 1/3 to 2/3, and then Erma poured the water out of the marble jar into an empty one, which became about half-filled. Ahah! About half the space in the marble jar had been filled with water, the other half with marbles! Neat! But then Erma did the same thing with sand! She filled a jar with dry sand, and asked the same questions. This led to much fascinating discussion, and then Erma gradually added water from a full jar to the sand jar. The sand at the top grew darker as the water soaked down into the sand and made it wet. And fine bubbles began to come up to the top surface of the water at the top of the jar. Air! Erma asked, "If a straw were to be stuck down into the jar where the sand is still dry, could air be sucked out to more rapidly fill the jar with water?" No one volunteered to try it, however. Now - how much water could we add to the sand-filled jar? More fascinating argument and discussion! Do you know the answer? Have fun!
Glenda Ellis (Williams School)
handed out rulers (metric), a Data & Observations page, and we each got several maple leaves. She had us measure and record (in cm) from the tip of each leaf to the bottom of its stem (Length, and then by having us raise our hands, she determined how many leaves had lengths of 7.0 cm, 7.5 cm, etc. up to about 13.0 cm. Using this data, a graph of the number of leaves (vertical axis) of a given length (horizontal axis) could be plotted, showing variation in leaf length. What an interesting idea! ...and such a good way to get students involved in observation, measurement, graphing, and possible interpretations!
Eartha Sherrill (Williams School)
handed out black construction paper (about 14x17 sq in), small cards (about 2x3 sq in) of different colors, piece of chalk, page listing objects under City Ecosystems (mice, grasses, cats, etc) and Pond Ecosystems (minnows, algae, frogs, etc). Looking at City Ecosystems, we entered on the small green cards the name of each "producer" (grass, weeds, vegetables, etc) The cards were placed in a line across the bottom of the black paper. Then on yellow cards we entered the first level names (consumers - mice, grasshoppers, etc. ) The idea of food chain was introduced, and the web of interconnections between various living things in the ecosystem. A beautiful way to analyze and see those interconnections, and to gain insight into what an ecosystem is!
Pat Riley (Lincoln Park HS)
passed out a pattern to cut out cloth and sew pieces together and make a stuffed mole animal. She showed us several completed "moles," a silvery one being a "mole of silver," a gold one being a "mole of gold," etc. Chemistry with as sense of humor! She held up a small "mole," and suddenly "tore" it in half! (Velco held it together). "What is this?" she asked. "Half a mole!" was the answer! And Earl Zwicker (IIT Physics) showed us a small silvery cylinder which weighed about 27 grams. An actual mole of Aluminum.