- Slides: 22
• Nuclear Decay Song on Youtube • • Animation of Alpha, Beta, Gamma rays on youtube • • radioactive dating using Uranium on Youtube • • Animation Explain Why Nuclear decay and emissions occurs • • One Half-life to Live Song on Youtube
2. Nuclear Radioactivity: a. Nucleus- composed of protons and neutrons b. Strong Force – causes protons and neutrons to be attracted to each other
c. Powerful only when protons and neutrons closely packed together d. Large nucleus is held less tightly than a small nucleus
3. Nuclear Decay which happens when the strong force is not large enough to hold the nucleus together a. The nucleus gives off matter and energy until they transform into a different isotope or another element
4. Isotopes atoms with the same number of protons, but different number of neutrons • Carbon-14 6 protons, 8 neutrons • Carbon-12 6 protons, 6 neutrons
Stability 5. An atom’s stability will depend on the ratio of protons to neutrons in the nucleus a. A nucleus with either too many or to few neutrons compared to protons is radioactive
6. POP QUIZ Explain why nuclear decay occurs.
7. History: a. 1896 – Henri Becquerel discovered radioactivity with the element Uranium
b. 1898 – Marie and Pierre Curie discovered radioactive Polonium and Radium
8. Nuclear Radiation - Particles and energy released from decaying nucleus There are 3 types: a. Alpha particles (a) b. Beta particles (b) c. Gamma rays (g)
9. Alpha Particles consists of two protons and two neutrons with an electric charge of +2. They do not travel far due to size and charge. Though they are the least penetrating form of radiation, they can cause serious damage.
Beta Particles (b): • electron emitted during the radioactive decay of a neutron into a proton in an unstable nucleus. They can travel farther and faster than alpha particles because beta particles are so small.
11. Gamma Rays (g): • high energy electromagnetic radiation emitted by a nucleus during radioactive decay. They have no mass and no charge. These rays can penetrate matter deeply, even buildings.
12. What are three types of decay we walked about? Alpha, beta, gamma
13. When an atom is radioactive, it is… • Unstable due to the number of neutrons, and will decay
14. Half-life of radioactive Isotopes a. The length of time it takes half of the atoms of a sample of the radioactive isotope to decay b. Varies from fractions of a second to billions of years c. Do you remember Plutonium’s half-life? 24, 000 yrs
15. How can we use radioactive half-lives? • Can be used to determine the age of old objects, such as: – Fossils – Rocks – Artifacts
16. Nuclear fission – process of splitting a nucleus into two nuclei with smaller masses
17. Chain reaction – an ongoing series of Fission reactions
18. Nuclear Fusion • Two nuclei with low masses are combined to form one larger nucleus
a. Can only happen when nuclei are moving fast b. Temperature must be high as the temperature of a star