1. Radioactivity
radiation

3. Nuclear Reactions
Chain reactions: the neutrons emitted during fission hit other atoms causing those nuclei to split also
Critical Mass: when each neutron emitted splits another atom

4. Nuclear Reactions
Nuclear reactions: 1938 Otto Hahn and Fritz Strassmann
Found that when you hit the nucleus of a large atom the nucleus splits and energy is released
nuclear reactions (10 minutes)
fission and fusion (11 minutes)

5. Charge of an Atom
The charge of an atom is determined by the number of protons in the atom’s nucleus
Negatively charged atoms are attracted to positively charged atoms

6. The Strong Force
The strong force: a short range force that causes protons and neutrons to be attracted to each other
100 times stronger than the electrical force

7. Radioactivity
Stable atoms: when the strong force is able to keep the nucleus together
Radioactivity: when the nucleus of an atom becomes unstable and decays giving off matter and energy
Example: anything over the atomic number of 83

8. Radioactivity
Unstable and stable nuclei: atoms with an unequal number of neutrons and protons are unstable

9. Discovery of Radioactivity
1896 Henri Becquerel

10. Nuclear Decay
Nuclear radiation: When an unstable nucleus decays and particles and energy are emitted from it
radioactivity

11. Alpha Particles
Alpha particle: a particle made of 2 protons and 2 neutrons
Alpha decay: when an alpha particle is emitted from an atom
The least penetrating form of nuclear radiation but it can damage human cells
Radiation

12. Beta Particles
Beta Particles: decay when an electron is emitted from the atom
Beta Decay: one of the neutron decays into a proton so the atom is not the same atom anymore
Damage is much more penetrating
Can damage human cells

13. Gamma Rays Gamma rays: electromagnetic waves that have the
Highest frequency, highest energy and shortest wavelength
Do damage to human cells

14. Half-life
Half-life: the time it takes for the nucleus to decay by half

15. Radioactive Dating
Radioactive dating: uses the half-life of atoms to date rocks and fossils
Carbon dating: uses the decay of carbon isotopes to date plant and animal remains
Accurate up to 50,000 years
radioactive dating

16. Radioactive dating
Uranium Dating: uses the decay of uranium to date rocks and fossils
Uranium has a half-life of 700 million years to 4.4 billion years

17. Detecting Radioactivity
Cloud chamber: a chamber filled with water vapor that is used to detect alpha or beta radiation
Bubble Chamber: a superheated liquid that will boil in the presence of radiation
Electroscope: detects electricity and can be used to detect radiation
Geiger Counter: a device that detects radiation by producing an electric current
Fukushima

18. history of radiation Chernobyl Fukushima
what could survive an atomic bomb?
the Manhattan project