Cloud Chamber
PURPOSE:
This exercise will demonstrate the radioactive emission from an element. The white lines in the cloud are tracks formed by radiation that was given off from the breakdown of a radioactive element. What happens is the radiation knocks electrons out of the atoms in the air. The alcohol vapor then condenses on the charged particles creating the white lines seen in the cloud.
MATERIALS:
- A small container with a transparent top. I use a tuna fish can with a plastic top.
- Some dry ice usually from a welding supply place or contact a fire company or emergency services that would have the address of a place.
- Dark blotter paper about two inches wide and long enough to fit inside the container on the wall.
- Some flat black paint.
- A flashlight.
- A silk gas camping lantern mantle or a radium painted watch dial still inside the crystal or fire detector guts for a radioactive source.
SAFETY:
Do not touch the dry ice with bare hands.
Watch out for sharp edges.
PROCEDURE:
- Paint the bottom of the container with the black paint. Allow the paint to dry
- Cut some blotter paper the same height and length around the can.
- Attach the blotter paper to the inside of the container.
- Pour a very thin layer of ethyl alcohol (or rubbing alcohol) in the bottom of the container. Also soak the blotter paper ring with the alcohol.
- Place the silk gas mantle or other radioactivity source on the bottom of the container and put the lid on tightly. Tape around the lid.
- Place the container on the "dry ice". Put your warm hand on top.
- After the container has cooled for several minutes, darken the room and shine a small flashlight through the plastic top from the side of the container.
RESULTS:
- Sharp tracks about one centimeter or one half inch long are alpha radiation. You can bend these with a strong magnet on one side of your container.
- The longer, thinner tracks are the result of beta radiation which are electrons.
- Gamma radiation causes twisting tracks that are very faint and difficult to see.
- Note: Your radioactive source is not pure so you might see all three types of radiation.
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This exercise will demonstrate the radioactive emission from an element. The white lines in the cloud are tracks formed by radiation that was given off from the breakdown of a radioactive element. What happens is the radiation knocks electrons out of the atoms in the air. The alcohol vapor then condenses on the charged particles creating the white lines seen in the cloud.
- A small container with a transparent top. I use a tuna fish can with a plastic top.
- Some dry ice usually from a welding supply place or contact a fire company or emergency services that would have the address of a place.
- Dark blotter paper about two inches wide and long enough to fit inside the container on the wall.
- Some flat black paint.
- A flashlight.
- A silk gas camping lantern mantle or a radium painted watch dial still inside the crystal or fire detector guts for a radioactive source.
Do not touch the dry ice with bare hands.
- Paint the bottom of the container with the black paint. Allow the paint to dry
- Cut some blotter paper the same height and length around the can.
- Attach the blotter paper to the inside of the container.
- Pour a very thin layer of ethyl alcohol (or rubbing alcohol) in the bottom of the container. Also soak the blotter paper ring with the alcohol.
- Place the silk gas mantle or other radioactivity source on the bottom of the container and put the lid on tightly. Tape around the lid.
- Place the container on the "dry ice". Put your warm hand on top.
- After the container has cooled for several minutes, darken the room and shine a small flashlight through the plastic top from the side of the container.
- Sharp tracks about one centimeter or one half inch long are alpha radiation. You can bend these with a strong magnet on one side of your container.
- The longer, thinner tracks are the result of beta radiation which are electrons.
- Gamma radiation causes twisting tracks that are very faint and difficult to see.
- Note: Your radioactive source is not pure so you might see all three types of radiation.