We are part of the
action this year for kids ranging from 4th to12th
grade. Morning and afternoon
classes, 3 hours each, makes for a full day.
One of the topics was
Cryogenics, the really cool science.
We were so busy we
didn't take many pictures but you can see some of
the experiments we did on the Cryogenics
They thought it was really cool (77 degrees K). Everyone
enjoyed liquid nitrogen ice cream.
Here is a video of one
of the experiments we did.
We put an couple of
hundred cc's of liquid nitrogen into a two liter plastic pop bottle. Put the
lid on and quickly dropped it into a 5 pound coffee can with about 2
water in it. Covered the whole works
with a 5 gallon plastic bucket and
got back about 120 feet. You see the
result. Calculations based on
measurements we made give a peak height for the bucket of 88
You should be aware that
fragments of the bottle landed more than 70
feet away from the launch point. So get way back if you
decide to repeat this.
We did take the class
pictures. Wait till you see what
we do with pictures later in the week.
We challenged them with
the Eight Queens problem at the end of
today's class and had several of them find multiple solutions.
If you want to try it
yourself there are the rules. In a standard game of
chess the queen is the most powerful piece It is able to attack any
other piece anywhere in its row, column, or
either of its diagonals. The problem to be solved
is to place 8 queens on the chess board with
none of them attacking any other. If you successfully
solve this problem mark each of the occupied
squares. Then solve it again
without using those squares. Repeat marking and
solving until it can't be solved again.
And we had more ice
We built and flew hot
air balloons in another class. First cut out the gores
from 8 layers of tissue paper. Carefully glue the edges
together to make the envelope of the balloon.
They are beginning to
Test to make sure that
all the glue joints are secure.
Carefully inflate them
with hot air. The winds were higher
than we would have liked for the flights. some of the balloons got
a little scorched during inflation.
Up, up and away. For the first flight
they were tethered so the balloons could be recovered for another one.
Some made only
flights so the kids could take them home.
Others were released to fly free either intentionally or accidentally.
Some of these were recovered, others were still high in the sky when we
could no longer see them.
Not all the balloons
made multiple flights. When a gust of wind
pushed this student's balloon to close to the burner it caught fire. The only thing left was
the wire that had been around the bottom of it. We were fortunate that
only three of them went into the sky this way.
We tried the game of
Nim today. The rules are simple it
is a game for two players You start with three
rows of markers (we used pennies) with any number of markers in each
Rows of 4, 5, and 6 are a good set to
start with Each turn a player may
take any number of markers from any one row. Then the other player
takes some from one of the rows. They take turns The player taking the
last marker wins.
Galaxies, the atomic
nucleus, and everything in-between is influenced
by the fields and forces that we investigated.
Science where they learned about electrostatic forces, very high
voltage and it's effects. They built an
electroscope from a pop bottle, a paper clip and a piece of mylar foil
gift wrap. Then used it to detect
electric fields and learned how electroscopes
are still used to monitor ionizing radiation.
They were able to light
a lamp with nothing more than a balloon, pie
pan and a straw.
The Van de Graaff
generator was a hit. When they were touching
the charged terminal their hairs were repelled from each other with
The charge wasn't enough
to lift the braids but any stray hairs were standing straight out.
They also had the chance
to see what electricity feels like!! Everyone got to try it
if they wanted to. Some didn't look like
they liked it but kept coming back for more.
We tried String Figures
and some magic at the end of the class. For instruction in how
to do some of them go to The
International String Figure Association site. For an introduction to
more easy string figures go here. Click here for lots more string figure
sites. To learn some magic
tricks you can go to this
The next day
we were so busy investigating electricity and magnetism we
only got one picture of one of the projects. This is a telegraph key
and sounder modeled after the original digital electrical communication. It uses electromagnetism
to detect the current from a battery when a switch is closed.
The class also got to be
part of a circuit, measure voltage and resistance, and power motors
with batteries. An
electric meter let them see which kind of light used more power and
whether a drill or a hair dryer took more when it was running. They also saw the effect
of eddy currents in copper and aluminum when a strong magnet moved near
them. And they had a chance to
check out some very strong magnets and ferrofluid. And they built magnet
field viewers too. Did I mention we were
Photography Friday it was time for
some light study. Do you know what is
going on when you take a picture? The kids got to look
inside the process.
They took a camera apart
to see what makes it
Then they built a camera
and used it to take a
The simple process we
used created negative images. I interchanged black and
white digitally to make the positive ones. Not bad considering the
cameras were made of baking pans, paper and tape.
The exposures were 4 seconds so the camera and subject had to be very
In this one you can see
the picture is reversed left/right.
Can you take a picture
light? They know how it can be done. When we take light
apart we can see what atoms are in the source. And you can do it with
just an old CD or DVD.
They learned how we see
in three dimensions (3D). Put on your red/cyan
anaglyph glasses and you will see the classes in 3D. At least the ones who
were able to hold still for two exposures.
Here they are in plane
(pun intended) old 2D looking at themselves in 3D.
The final challenge for
the week was solving some Tangrams. If you want to try some
yourself figures and solutions can
be found here. More figures and
solutions. This time in French are here. And even more Tangram