Winifred Malvin (Carter School) Handouts: Oxygen; Products of
On the desk she put an assortment of jars, bottles, pie plates, candles, and matches. She placed a burning candle on a pie plate with a high flange that contained water to a depth of a few cm. Then, she put a jar over the burning candle. The candle burned for a while, and then went out. As we watched, the water level in the jar began to rise.
What happened?The burning candle, which contains hydrocarbons, produces carbon dioxide CO2 and water vapor H20, while consuming oxygen O2. The water vapor tends to condense rather rapidly onto the walls, and condensation is visible. The water level rises as the volume of the gas decreases because there is a decrease in the gas pressure inside. This occurs in part because of condensation of water vapor, and in part because of the decrease in temperature after the flame dies down. We all went to the table and repeated the experiment. One of us tried it with burning paper, and found the same effect. One gets the same by-products from burning paper: water and carbon dioxide.
Why did the water level rise in the jar?
|CO2||Carbon Dioxide Gas|
|H20||Water (liquid or vapor)|
|Gravity||(keeps things on the ground)|
|Solution A||1 part Joy™ Dishwashing Liquid
3 parts distilled water
|Solution B||1 part Joy™ Dishwashing Liquid
3 parts distilled water
1 part glycerin
|Solution C||Miracle Bubbler™
available bubble solution
We had a great deal of fun making bubbles and keeping them afloat. If time had allowed, we each would have predicted which solution would allow us to make the longest-lasting bubble, and then tested the hypotheses. Note that glycerin is typically added to bubble solutions because it keeps water from evaporating, resulting in longer-lasting bubbles.
Glenda Ellis ( Williams School) Handout: Right or Wrong
Jeremiah, a hapless student visitor, agreed to try to identify small chunks of food from their taste alone, without seeing what he ate (that is, while seated and blindfolded). The question was whether he could tell the difference in a potato and an apple. Here are the results
Everybody came up to the table to do their own taste/smell experiment with the food chunks and with a partner. We tried to confuse the partner's taste by putting an onion under the nose.
Marie Wong (Warren School)
Notes taken by Earl Zwicker
Section B: [4-8]
Sally Hill (Clemente Park HS) M&M's Activities
Sally passed out small bags of M&M's to each of us, and asked us to estimate [guess!] how many pieces of candy were inside our bag. In addition, we guessed the colors from the six colors shown on the package:
The average number in the package of ordinary M&M's was near 25, and the most common color seemed to be brown. It was suggested that brown ones were easier to make, since the interior is made of brown chocolate, with a colored sugar coating.
Sally also handed out special Valentine's Day bags of M&M's. We decided that they were special because there were fewer of them in the bag (22 versus 25) and because they cost more! We recorded data in the following format [data taken by Porter Johnson are shown]:
|Color||Ordinary M&M's||Valentines M&M's|
Billions and billions of years ago, life as we know it arose from this primordial chocolate ooze...
Actually, the story of M&M's® began thousands of years ago - the Mayan and Aztec civilizations of Central America used to make a drink from the beans of the cacao tree. Spanish colonists brought the drink back to Europe in 1528, but it wasn't until over 300 years later that a method was found to produce solid chocolate.
Zoris Soderberg (Clark School)
She once again emphasized the K-Method for Effective Teaching:
How do we know that Oxygen is the active ingredient in air? She put a powder inside test tubes, gave one to each of us, and also gave us a wooden splint [coffee stirrer]. Then she poured a clear liquid into each test tube, and it began to interact with the powder already there, producing bubbles and foam. Then we each lit our splints and blew them out, quickly inserting the splint with glowing embers into our test tube. To our delight, we saw the embers on the splint burst into flame inside the test tube, indicating that oxygen was being produced in the reaction.
What happened? The powder was obtained from a package of cooking yeasts, and the liquid was Hydrogen Peroxide, H202. The enzymes in the yeast served to catalyze the chemical reaction that produced free Oxygen -- 02:
There was discussion as to whether the yeasts had to be alive to catalyze this reaction. The feeling was that they probably should be, although the chemical reaction is different from that in baking bread. In the latter, one catalyzes glucose C6H1206 to produce ethyl alcohol C2H5OH and carbon dioxide CO2:
This chemical reaction is the same as than in brewing ethyl alcohol from mash. Most of the ethyl alcohol evaporates during the baking process, but bread does contain a small residual amount of ethyl alcohol.
For the coup de grace, she put a full package of cooking yeast into a large jar [liter/quart], and added about 50 ml of Hydrogen Peroxide. Then, she held a piece of steel wool inside the jar, and put the glowing splint inside, as before. The steel wool burst into flame and burned to glowing embers in the oxygen-enriched atmosphere. Why did that happen? Very impressive, Zoris.
Don Kanner (Lane Tech HS) Sound
He introduced the following terms relating to sound waves:
|f||Frequency (number of oscillations per second)|
|l||Wavelength (peak-to-peak distance)|
|v = f ´ l||Connection of speed, frequency, and wavelength|
He illustrated the point another way by blowing over the lip of a partially filled plastic bottle [250 cm3] producing a fairly low pitched sound. Then, he drank some of the fluid in the bottle, and blew again. The pitch was definitely lower. Since he had made the region of air in the bottle larger, sound was produced at a larger wavelength, and the frequency or pitch was reduced. Simple, non?
The shape of musical instruments determines the amount and pitch of sound that comes out of them. Don illustrated this in several ways:
His presentation is based upon the 1989 Royal Institution [London] Christmas Lecture Video entitled What is Music?, given by Professor Charles Taylor. For additional references on musical acoustics see the websites http://www.phys.unsw.edu.au/music/ and http://www.acoustics.org/press/137th/rossing1.html.
Porter Johnson then told a Physics Joke:
Marva Anyanwu (Wendell Green) Handout: Floating in Space
(Scholastic Inc 2001)
She mentioned that the International Space Station [ISS] has been occupied by astronauts since November 1999, in an environment of Weightlessness, or Micro-gravity. To illustrate the effect of this apparent weightlessness, she took a transparent plastic jar, cut a large rubber band, and suspended it inside the jar, after placing a small amount of putty on its end. The rubber band was held in place at its top end as she tightened the the lid of the jar on it. The rubber band was stretched by the weight of the putty at its free end. Then, she dropped the plastic jar.
Notes taken by Porter Johnson