Barbara Lorde [Attucks Elementary School]         Name that Element (an activity she brings us from her recent summer program at Columbia College)
Barbara started by pointing out the elements in our chart of the Periodic Table on our wall and reminding us that our own bodies are composed of many of these elements. Barbara then gave us bags of beans, each bag containing two types of beans (black for neutrons; white for electrons-protons—to simplify things, each "proton- electron pair" was represented by a single white bean). Using a periodic table, we arranged the beans in each bag to form atoms and then identified the corresponding element represented by the beans in each bag.. For example, one bag had 19 white and 20 black beans (atomic number Z = 19 and atomic mass A = 39; therefore ₁₉K³⁹, where K stands for Kalium -- the Latin word for potassium).

Ken Schug [IIT]                 Ken's mysteries!
Ken had a stoppered Erlenmeyer flask almost filled with a blue liquid with a pipette vertically held in the stopper with one end submerged in the flask and some of the blue liquid in the pipette. He put the flask on ice to cool. The column of the blue liquid in the pipette slowly fell as the temperature of the liquid decreased, because of a decrease in the volume of the fluid.  It worked as a thermometer! Ken then pulled out a very long thermometer, which we presumed to be useful over a large range of temperatures. But it had a very large mercury bulb compared to its size, which allowed this huge thermometer to range only over 13 Celsius  degrees, and thus be very precise.

Wanda Pitts [Vernon Community Academy]                   Magnets (handout)
Wanda passed around the article Attractive Spirals from the book Janice VanCleave's Magnets: Mind-boggling Experiments You Can Turn Into Science Fair Projects:  http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471571067.html.  She began by asking us what we know about magnets. We came up with the following:

• they have North and South poles
• things containing iron stick to them

Ken pointed out that one may wrap aluminum foil around the nail  in making an electromagnet. It does not short out against the nail because the foil is coated with a non-conducting coat of aluminum oxide  Al₂0₃ (i.e., the foil surface is naturally insulating).

Other connections between magnets and biology /chemistry:  MRI imaging, helping birds migrate (by following the magnetic field of the Earth).

Ed Scanlon  [Morgan Park HS, Biology]                 Impact Craters (handout)

• Objectives: To form impact craters.  To understand the formation and structure of impact craters.  To associate crater size with the Potential and Kinetic energy of the impacting object.
• Introduction: When we want to find out how big an object was that caused a crater or when we want to find out how big a crater will be from the impact of an object, we should figure out both the potential energy and kinetic energy of the object.
  Potential energy is the energy an object has because of its position or configuration. The formula for potential energy due to gravity is PE = m g h, where m is the mass, g is acceleration due to gravity, and h is the height.
  Kinetic energy is the energy an object has because of its motion. The kinetic energy of an object with mass m and speed v is found by the formula KE = 1/2 m v².
• Purpose: To find out how mass and height affect the size of a crater.
• Materials: Balance, meter stick, pan with sand in it, table tennis ball, marble, golf ball, ruler, salt.
• Procedure: Sprinkle a thin layer of salt over a pan that has sand in it -- just enough salt to cover the sand. Drop the balls from various heights (10 cm, 100 cm, 200 cm), and measure the distance across the resulting crater. Repeat for the marble and golf ball. Draw a graph of crater width versus drop height for each object. Discuss.

Some useful information for this experiment is the masses of these three "projectiles":

A big enough object traveling fast enough could potentially make a huge crater on impact with the earth, and eject a huge amount of dust/debris into the atmosphere. One widely held view (for which there is considerable evidence) is that such an impact created so much dust in the atmosphere that a huge global cooling occurred, leading to the extinction of the dinosaurs and other species. For details see the Smithsonian National Museum of Natural History website:  http://www.nmnh.si.edu/paleo/blast/k_t_boundary.htm.

Notes prepared by Benjamin Stark.