Radioactivity and Nuclear Reactions

Page
8

Radiation knocks electrons off the gas which are attracted to the wire producing a current.

Slide 68

Measuring Radiation

An amplifier strengthens the current producing a clicking sound or a flashing light.

The number of clicks or flashes per second tell how strong the radiation is.

Slide 69

Background Radiation

The air, the ground, & even the walls of your home give off radiation in small amounts.

Slide 70

Background Radiation

The air, the ground, & even the walls of your home give off radiation in small amounts.

Radioactive isotopes that occur in nature emit background radiation from rocks, soil, air, bricks, wood, stone, food, water, animals, plants, etc.

Slide 71

Where does background radiation come from?

The circle graph shows sources received on average by a person living in the US. Decay of U-238 in the soil produces radon gas which can move into houses & basements.

55%

11%

8%

4%

8%

3%

11

Slide 72

Where does background radiation come from?

Cosmic radiation is greater at higher elevations where there is less atmosphere to absorb it.

Background radiation comes from natural processes.

55%

11%

8%

4%

8%

3%

11

Slide 73

Nuclear Reactions

What You’ll Learn

What nuclear fission is

What nuclear fusion is

How radioactive tracers can be used in medicine

How nuclear reactions can help treat cancer

Slide 74

Nuclear Fission

1934- Enrico Fermi bombards U nuclei with neutrons.

Slide 75

Nuclear Fission

1934- Enrico Fermi bombards U nuclei with neutrons.

1938- Otto Hahn & Fritz Strassmann split U-235 into smaller nuclei.

Slide 76

Nuclear Fission

1934- Enrico Fermi bombards U nuclei with neutrons.

1938- Otto Hahn & Fritz Strassmann split U-235 into smaller nuclei.

1939- Lise Meitner theorized that splitting occurs when the nucleus becomes so unstable that it splits.

Slide 77

Nuclear Fission

1934- Enrico Fermi bombards U nuclei with neutrons.