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NOTES FROM THE FIELD
Weighing Activity
This great idea for an extension to the FOSS Measurement
Module (pdf) was posted on the FOSSweb bulletin
board in October 1999 by Roxanna Rickly. It has also been
suggested as an extension to the
Food and Nutrition
Module (pdf).
I have my students bring in pop cans or snack food wrappers.
We check the labels for the amount of sugar and fat. The students
then weigh the given amount of sugar and place in a snack-size
zip bag. They can weigh Crisco for the fat, or to keep things
a little cleaner, we substituted white playdough. The snack
wrapper and snack bag of sugar and fat are hot-glued onto
index stock and then hung in the hallway. As a class we tabulated
the amounts of sugar and fat for the different snacks and
graphed them on the computer using a spreadsheet program.
Adopt a Wheat Field
This website suggestion came from Cindy Garwick, a first grade
teacher at Bluemont Elementary School in Manhattan, Kansas.
Go to this URL, http://www.oznet.ksu.edu/wheatpage,
and click on Kids Corner (right side of screen) and
then go to Adopt a Wheat Field.
Kansas State University agronomist Jim Shroyer picked a spot
in a wheat field north of Manhattan, Kansas, to show the cycle
of wheat from field preparation in August to bread the following
July. The photos are great! Use the "Adopt a Wheat Field
Calendar" to click on dates to move through the photos
you want students to view. At the primary level the text is
informational for the teacher, but students love the photos
(as you can see from the photos here).
This website is the perfect way to incorporate technology
with the planting of a wheat seed in a straw activity found
in the FOSS New
Plants Module. Students can compare their wheat
growth with what occurs in the fields of Kansas.
First-grade students from Bluemont
Elementary School in
Manhattan, Kansas go online for a "Wheat Watch."
Bluemont Elementary School students
watch wheat grow online
as an extension to the FOSS New Plants Module.These seedlings
are the results of the Bluemont students investigations.
You can communicate with Cindy at
Bluemont Elementary School
714 Bluemont
Manhattan, Kansas 66502
E-mail: cindyg@manhattan.k12.ks.us
Phone: 785-587-2030
Spring Scales!
This letter from Oklahoma City came via e-mail to Larry Malone
regarding the spring scales used in the FOSS Levers
and Pulleys Module (pdf).
Dear Foss:
I am teaching in a summer science academy that brings together
master teachers, potential teachers, and students in grades
2-8. The curriculum that we are using is the FOSS Levers and
Pulleys Module. As master teachers, we taught the unit to
the potential teachers prior to the students arriving at the
academy. As our potential teachers explored the use of the
spring scales, they reached a dilemma!
Our question to FOSS is: Why do you have to use a spring scale
right side up? Why can't it be used upside down?
We discovered that the spring scale measured 2.4N with the
load right side up. Hanging the load on it upside down and
reading the scale, gives you 2.9N so that you do not need
to add the .5N when reading it. If you "zero it out"
with the weight upside down, then you get 2.4N and have to
add the .5N, giving you a 2.9N reading just like you get right
side up. We have puzzled over the workings of the spring scale
for 2 weeks! Can you satisfy our questions for us? Thanks
for your help!
Betsy Mabry
betsymabry@yahoo.com
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Larry wrote:
Hi Betsy...
OK, here's the deal. When you hold the scale in the usual
manner, by the bail (loop) at the top, the only mass pulling
on the scale spring is the mass of the hook. By zeroing the
scale to compensate for the mass of the hook, you are ready
to go. Any additional force applied to the hook (a mass responding
to the acceleration of gravity, a person yanking on it, a
magnet attracting it, etc.) will stretch the spring. The amount
of stretch is a measure of the force.
Let's say you put a 500g mass on the scale. The scale will
register 5N.
However, if you hang the scale-and-500-g-mass system on a
second scale, the second scale will read 5.5 N. This is because
the total force pulling on your hand is the sum of the mass
on the hook plus the mass of the scale. So, when you attach
the bail to a lever arm and pull down on the hook to measure
the force acting on the lever, you read the scale and add
the 0.5 N that represents the force contributed by the mass
of the scale to determine the total force pulling downward.
When you pull upward in the usual way, you are supporting
the mass of the scale...it is not contributing to the force
acting on the spring.
Always look at the lever where the force is being applied.
What is pulling on it at that point? If the mass of the scale
is pulling, add in 0.5 N to account for its mass.
And why do we always use the scale right side up? Because
it is easier to read.
Good luck and congratulations on using the Levers and Pulleys.
Have you encountered Sparky the pony yet? He's in the math
section of one of the pulley investigations (revised version).
Regards.
Larry
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Betsy replied:
Larry,
Thanks so much for your prompt reply! What you wrote were
observations that we had made, but it was fun to include FOSS
comments. I never realized that a spring scale would be as
intriguing as it has been for us! The interest was peaked
by two of our "potential teachers" who are working
with the academy and who are 2001 high school graduates.
As far as Sparky is concerned, we are using a "real-world"
Oklahoma application instead!
Construction of a dome on our State Capitol has begun. Today
a massive structural beam is being raised in Oklahoma City.
We challenged our students to construct a pulley system that
would raise a poster board dome to the top of the second floor
"capitol roof" in the Commons Area at NWOSU where
our academy is taking place. The kids had a wonderful time
working together to make it happen!
After the "Efforts in Pulley Systems" tomorrow,
we will guide them toward the ultimate "Survivor Challenges"
using levers and pulleys.
Thanks again for your help.
Betsy Mabry
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