This document discusses clouds and cloud chambers. It begins by providing basic information about clouds, such as their composition of water drops or ice crystals floating in the sky. It then discusses C.T.R. Wilson, the physicist who invented the cloud chamber and used it to photograph tracks of particles. The rest of the document provides details on how cloud chambers work, what types of particles can be observed (alpha, beta, muons), and safety tips for operating a cloud chamber, such as using dry ice and isopropanol.

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カガクの粒

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Cloud
Chambers?

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Does this cloud
mean the cloud
in the sky?

4. Nacreous clouds over the NASA Radome,
McMurdo Station, Antarctica, Wikipedia 2018 kagakunotsubu
Various kinds of Clouds

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Various kinds of Clouds
Lenticular Cloud over Harold's Cross

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Various kinds of Clouds
Mgla fog Loenstrup Denmark North Sea, Wikipedia

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Various kinds of Clouds

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We can see clouds in a bathroom!

9. Q：What are clouds？
A：A cloud is made of water
drops or ice crystals
floating in the sky.
NASA Knows! for Students K-4,

10. ！
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Water Drops
Floating
in the sky!

11. Water drops are too small to see,
moving at extremely high speed.

12. When the temperature of the air
falls down,

13. and something stimulates it,
tiny droplets become visible.

14. The very moment
when tiny invisible particles
become visible is …

15. How to Love Clouds, by Kentaro Araki,
Kobunsha Co., Ltd., Tokyo 2017:12
Contrail

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Who came
across the basic
idea of the cloud
chamber for the
first time?

17. C.T.R Wilson
（Physicist）
Born on the 14th of
February, 1869
Early in 1911, he was the first
person to see and photograph the
tracks of individual alpha- and
beta-particles and electrons.
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C.T.R. Wilson
Worked at the Cavendish Laboratory in Cambridge.
Was awarded the Nobel Prize for Physics in 1927.
“His sharp observation and keen intellect, however, led
him to suspect (after a few months’ work at the
Cavendish Laboratory) that the few drops reappearing
again and again each time he expanded a volume of
moist, dust-free air, might be the result of condensation
on nuclei - possibly the ions causing the “residual”
conductivity of the atmosphere - produced
continuously..”
- C.T.R. Wilson Biographical; The Nobel Prize

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What
I can see
in my cloud
chamber is…

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α particle
A nucleus of helium, flying rapidly.
This particle cannot pass through one piece of paper.

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β particle
An electron or positron, flying rapidly.
This particle cannot pass through an aluminum board with a
thickness of 5mm.

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muon
Particles, which let us know the
cosmic particles’ arrival on the earth.
This particle is crossing the earth all the time, at the rate of one
particle per 1cm square for one minute.

23. For more details
【Japanese】
有限会社ラド 『霧箱とは』
http://www.kiribako-rado.co.jp/what.html
【English】
*CERN “How to make your own cloud chamber”
https://home.cern/news/news/experiments/how-make-your-own-cloud-
chamber
*CERN, S’Cool LAB
Woithe, J. (2016). CLOUD CHAMBER. S’Cool LAB - Do-it-yourself manual
https://scool.web.cern.ch/sites/scool.web.cern.ch/files/SCoolLAB_CloudCh
amber_DIYManual.pdf
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What I
should prepare
for the
observation is…

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Torches
Dry ice
Isopropanol
Pay attention particularly to

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Isopropanol
In case that you accidently touch the isopropanol,
wash your hands immediately.
Smell of strong liquor Flammable
Easy to burn and invisible flame

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Temperature on the surface of dry ice is approximately
Dry ice
Don’t touch directly.
Extraordinary low temperature
could be a risk of frostbite.
Wear your globe.

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Torches
Don’t Point your torch at somebody
Take a rest when you feel tired.

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Keep on observing
patiently, even though
tracks don’t seem to
be visible at first.

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The more I learn,
the more I
realize how much
I don’t know…

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Enjoy Science,
having fun and learning more!