Barbara also showed us a cloth panel of the solar system (about 3 x 3 sq ft), purchased at Hancock Fabrics at 30 - 31st St & Halsted. Glows in the dark and cost about $6. Introduces students to the planetary system in a very colorful way, with names and moons. Students could make such a thing from scratch into a quilt, and its good for shapes, sizes, ordering, etc. More good ideas!
Barbara Baker (Doolittle West School)
asked us, "What is photosynthesis?" - to which we ultimately answered, "The process by which plants utilize sunlight to make food for themselves." Barbara set up an experiment (handout). At the bottom of a jar was grass blades and dandelion leaf, with a glass funnel inverted over them. A narrow jar rested upside down on the funnel, with the stem of the funnel sticking up into the jar. The narrow jar was filled with a solution of baking soda (2 g in 200 ml water), and the other jar was partly filled. One would look for gas bubbles to rise up from the leafy stuff and through the funnel up into the top of the narrow jar. The rate of bubble production would be observed both in a darkened room and with the jar placed in sunlight. Unfortunately, the narrow jar wasn't long enough to fit down over the funnel as it should (...emphasizing the importance of making it work before trying it on your class!), but we got the idea - which is a good one. Thanks, Barbara!
Marva Anyanwu (Green School, science K-12)
introduced us to simpe machines (handouts). We saw how to make a crank (wheel & axle) using a paper cup, ballpoint pen, flexible drinking straw, string and washer - which resulted in a windlass. We listed some machines and pointed out some that were in the room around us. Marva introduced us to gears - and we identified the driving gear and the driven gear, and from drawings and counting number of teeth, calculated gear ratio. One may use plastic jar lids and glue corrugated paper around their edges to make gears. Also, Marva had us make Oreo cookie "gears" drive one another. A tasty idea!
Ed Scanlon (Morgan Park HS)
showed us a chemical reaction we could see! (handout) Lead nitrate (clear) plus potassium chromate (light yellow - clear) formed lead chromate (bright yellow precipitate). Filtration left the lead chromate on the filter paper, looking like paint when dried. Then Ed got us into toxic heavy metals: mercury and lead. Use EDTA for a child who had ingested lead through paint chips. Good stuff, Ed!
Melinda Ross (Hefferan School, 8th grade)
gave us a lesson on biodiversity (handout). We considered how different plants (& animals) have adapted to different places: cactus, oak tree. Why doesn't cactus have leaves? Species are disappearing at the rate of one every 3.5 minutes. An exercise brought this home. And then we each listed 5 foods, 5 places, 5 things. Eg. popcorn, Cape Cod, Swiss Army knife, etc. Then we had to cross out 5 things. Made us feel disappointed. To go on we would seek alternatives. extinction is forever! You made the point, Melinda!
Earnie Garrison (Jones Commercial HS)
briefly showed us "Pigs in Space," to top things off! The device he used is available from American Science Center, and is called a Mirage. It consists of two concave mirrors facing each other, with a hole at the center of the top one. An object placed at the center of the bottom mirror produces a real image at the hole in the top mirror. It sure looks real, all right! A true optical illusion!