R12e(cloud chamber)

The "cloud chamber" that does not require dry ice.

PURPOSE:

Cloud chambers are used for teaching about

[Radiation]

This cloud chamber does not need dry ice for cooling. It uses "ice gel" for cooling device, and this cloud chamber can be used many times when re-freezed in a freezer.

TARGET:

Junior High School (9th grade)

High School

CATEGORY:

Physics

Chemistry

HOW TO MAKE:

[Materials]

for cloud chamber

plastic cups ... 2

aluminum tape

felt

for cooling device ("cold plate")

heatsink ...1

"ice gel"(Frozen Sheet – 18OC, Ruck Stone Co. Ltd. )

aluminum tape

- Remove the bottom of one plastic cup*.

- Cover the hole with the aluminum tape.

- Cut some felts as the same size as the hole.

- Stack three felts and secure with a stapler.

- Stick felts inside the cup*.

- Fix two cups together and secure with aluminum tape.

- Wrap aluminum tape around the heatsink.

- Pour "ice gel" inside the heatsink.

- Seal the heatsink with aluminum tape.

The cross-view is shown in Fig1.

HOW TO USE:

- Put the "cold plate" in the freezer for more than 24 hours.

- Place the radiation source on the "cold plate".

- Warm ethanol to about 60oC.

- Pour 6mL ethanol to cloud chamber's felts.

- Put the cloud chamber on the "cold plate".

- Pour 100mL warm water into the upper cup of the cloud chamber.

- You will be able to see the particle tracks in about 1 minute.

Particle tracks will be seen as in figure 2.

REFERENCES

Masahiro Kamata and Miki Kubota, "Simple cloud chambers using gel ice packs", Phys. Educ. 47 429-433, (2012)