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Re: [Phys-l] outdoor experiments



One very similar method for sound-speed measurement is to have a student (via clapping, or with a drum) form a "sing-around" system with a building which will make a nice echo (it works with two students, but they seem to have a harder time synchronizing, even when they're told to close their eyes and *listen* instead of looking at each other). The student starts out clapping, and is told to adjust their rhythm so that their next clap goes out at the same time as the echo arrives. So long as they're more than about 50 meters from the building (even 25 meters for some very good drummers), the rhythm is easy to pick up. Another student can time a number of claps, and from that deduce the speed of sound.



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________________________________
From: Jeffrey Schnick <JSchnick@Anselm.Edu>
To: Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu>
Sent: Sun, March 14, 2010 7:05:00 PM
Subject: Re: [Phys-l] outdoor experiments

Roberto,
Ken's suggestion that you measure the speed of sound reminds me of an
old favorite. You need a large field or a pretty long section of empty
road, some means of measuring a distance in the hundreds of meters, and
a drum. Have a student bang on the drum once every second (perhaps in
synchronization with a simple pendulum whose length the students have
calculated for this purpose). A group of students walks away from the
drummer while looking back at the drummer. After a while, the sound
gets to them after they see the drummer hit the drum--the drummer
appears out of sync with the sound of the drum. If they keep on walking
and looking back however, eventually it again looks and sounds as if the
sound of the drum strike is arriving just as the drummer hits the drum.
Actually, they're hearing the sound when the drummer hits the drum the
next time. Thus, the distance they are away from the drummer is the
distance that sound travels through air in a second. (Assumes that it
takes no time at all for the light from the drummer to get to them. Not
having a big enough field or a drum when I did it, we used a wooden box
and a half-second time interval between bangs on the box. To get the
distance, you might have each student walk a known distance and count
how many steps it takes. They can use that to find the distance they
travel in one step--a piece of information that they might want to
memorize as it might be useful to them for more than just this one
exercise. Knowing how far I travel in one step has come in handy for me
more than once.)
Jeff Schnick

-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
bounces@carnot.physics.buffalo.edu] On Behalf Of Ken Fox
Sent: Saturday, March 13, 2010 6:47 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] outdoor experiments

Observe cars starting from a stop light, or just passing by, to plot
d=t
graphs......causes a lot of paranoia. ;-)
Use a car and force scales to do F = ma
Use a bicycle to examine stopping distance as a function of tire
pressure.
Bicycle riding in a circle and measure angle of lean vs speed and
radius.
Speed of sound with echos from a wall of a loud noise or time to hear
a
distant but visible clank
Sound wave interference from two monotonic sources.
Polarization of sky light....fun to observe, not so sure of
experimentation
Absorption of solar energy by water ...time, color of receptacle,
angle
of
sun....

There are a few.....nothing electrical....

Ken Fox

On Sat, Mar 13, 2010 at 4:10 AM, roberto <roberto03@gmail.com> wrote:

hello,
i am a physics and math high school teacher;
thanks for this excellent mail list !

i'd like to ask you information about possible outdoor experiments
you
do or have done in the past;
by outdoor experiments i mean a wide range of experimentations that
can be carried outside and not simply inside a lab; i think it may
be
fun and engaging to study the behavior of some physic system taken
as
it is and not artificially reproduced in a lab;

of course, it may be only a preliminary phase, since many
experiments
should also be carried inside the lab as always;

if it is not really clear what i mean, just tell me and i'll reply

thank you in advance
--
roberto
_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l

_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l