Announcements:
Section A: [K-5]
Barbara Lorde (Attucks School) Exploring Triangles, Rectangles,
Circles, and
Squares
She has been teaching for a long time, and has a third grader to type
up her
lessons for her. Her purpose was to introduce shapes and make
designs.
She cut down on some of the activity by cutting out the shapes
herself. We formed groups to arrange patterns on paper. One
group
made a rectangle, measured its length and width with a ruler, and
computed its
area using the relation (third grade activity on Math Skills)
Area = Length ´ Width
Leticia Rodriguez (Peck School, First Grade)
provided a variety of activities
relating to volcanoes, including a video of Magic Sound Bus Blows
Its Top.
She showed a Volcano Kit, which makes a correspondence between
volcano parts
[lava, magma, ring of fire] with parts of a boiled egg [yolk,
egg white,
shell]. This was a very rich presentation of information and
visualization on the environment, which introduced big words and made
them easy
to understand. She gave us instructions on making a volcano from
scratch, and
presented it as a scientific experiment with hypothesis, data, and
conclusions
to employ the scientific method.
She showed us the invisible Ring of Fire on the Globe. See the websites
Jean Essig (Woods School,
Kindergarten) Air Science Tricks
made a Hot Air Snake, and caused it to spin and spin and
spin. She
invited us to make our own snakes from colored paper. More than ten of
us were
soon showing how our snakes moved up and down like spiral springs.
She also
suggested several extensions:
Mamie Hill (Woods School)
used dried peas and toothpicks that had been soaked overnight to make
all
kinds of figures, including three dimensional figures. Soaking
provides
flexibility and softness that greatly simplifies the construction of
figures.
When the peas dry overnight the figures become stable.
Beverly Merchant (Soujourne of Truth School)
made colorful and sparkling shapes out of pipe cleaners using an Epsom
Salt
[Magnesium Sulfate] solution. She put a shaped pipe cleaner into the
saturated
solution, and the salt crystallized out along the pipe cleaner. People
were
given their cups of solution and pretty colored pipe cleaners, for
making their
own shapes and showing them next time.
Notes taken by Earl Zwicker and Bob Foote
Section B: [4-8]
Roy Coleman, Lee Slick, and Kerri Kerfin (Morgan Park HS)
How to
React to An Experiment
led a measurement of reaction time (to check to see if you are
still
alive).
The idea is for one person to drop a meter stick held vertically, with its bottom at the top of the fingers of (partially opened) hand of another person, which is resting on a table top. The first person drops the meter stick, and the second catches it as quickly as possible. The meter stick typically falls a distance s of 20 - 30 cm, corresponding to a total reaction time (t) determined from the formula s = 1/2 g t2 ; or s [cm] = 490 t[sec]2
s (cm) | t (sec) |
11.0 | 0.15 |
19.6 | 0.20 |
30.6 | 0.25 |
44.1 | 0.30 |
They estimated the first time by setting up two funnels attached with rubber tubing and held from behind at the ears of a participant. When the tubing was tapped, the participant was able to hear which ear heard the sound first and louder, unless it was tapped within s = 5 - 10 cm of the middle of the tubing. Thus, the Brain Processing Time is given as s / Vsound = 0.0003 sec. The finger closing time is estimated by seeing how quickly the fingers can be opened and closed [about 30 times in 10 seconds, corresponding to a closing time of 0.167 sec.] They then conclude that most of the time is associated with the Finger Closing Time, and that the Nerve Transmission Speed is comparable to the velocity of sound, or about 300 meters/sec.
Comments by Porter Johnson: The nerve transmission speed is certainly not larger than the speed of sound, and most estimates indicate that it is considerably smaller. Check these references:
A further foundational issue concerns the speed of human thought. In the 19th century, many believed that thought was either instantaneous or else so fast that it could never be measured. However, Hermann von HELMHOLTZ, a physicist and physiologist, succeeded in measuring the speed at which signals are conducted through the nervous system. He first experimented on frogs by applying an electric current to the top of a frog's leg and measuring the time it took the muscle at the end to twitch in response. Later he used a similar technique with humans, touching various parts of a person's body and measuring the time taken to press a button in response. The response time increased with the distance of the stimulus (i.e., the point of the touch) from the finger that pressed the button, in proportion to the length of the neural path over which the signal had to travel. Helmholtz' estimate of the speed of nerve signals was close to modern estimates -- roughly 100 meters/second for large nerve fibers. This transmission rate is surprisingly slow -- vastly slower than the speed of electricity through a wire. Because our brains are composed of neurons, our thoughts cannot be generated any faster than the speed at which neurons communicate with each other. It follows that the speed of thought is neither instantaneous nor immeasurable.
Beth Womack (Gunsaulus School) Bridge Design (Project-Based Learning)
provided the groups with a supply of the following materials:
Clay, Craft
Sticks, Tape, and Newspaper, and presented us with the following
questions:
Barbara Pawela (retired) Seeing the Invisible
Notes taken by Porter Johnson