Nuclear Reactions
• Nuclear Decay Song on Youtube• • Animation of Alpha, Beta, Gamma rays
on youtube• • radioactive dating using Uranium on You
tube• • Animation Explain Why Nuclear decay a
nd emissions occurs• • One Half-life to Live Song on Youtube
Lesson 2: Nuclear Decay
• Nuclear Radiation - Particles and energy released from decaying nucleus
• 3 types:– Alpha particles (a)– Beta particles (b)– Gamma rays (g)
Alpha Particles
• particle that consists of two protons and two neutrons with an electric charge of +2–Like a Helium
nucleus
Alpha Particles• do not travel far due
to: – Massive size
• Are the least penetrating form of nuclear radiation
Beta Particles (b):
• electron emitted during the radioactive decay of a neutron into a proton
Beta Particles (b):
• travels further through matter than alpha particles
• fast moving because it is so small
Gamma Rays (g):• high energy electromagnetic
radiation emitted by a nucleus during radioactive decay
• Have no mass and no charge• can penetrate matter deeply,
even buildings
Gamma Rays (g):
Lesson 4: Half-life of radioactive Isotopes
• The length of time it takes half of the atoms of a sample of the radioactive isotope to decay– Vary from fractions of a second to
billions of years
Radioactive Decay Rates
• Radioactive decay is used to determine the age of old objects. – Carbon-14 dating can be used to date once-
living materials from the past 50,000 years– Uranium dating cam be used to date rocks
Radioactive Decay Series for I-131
Radioactive Decay Series for I-131
Original sample
Radioactive Decay Series for I-131
1- half life
Radioactive Decay Series for I-131
2 – half lifes
Radioactive Decay Series for I-131
3 – half lives
Isotope Half - lifeK-40 1,280,000,000 years
Pt-239 24,120 years I-131 8.1 days Th-219 0.000 001 05 s
Examples of Half-lifes for different Isotopes
Lesson 5: Nuclear Reactions: Nuclear fission
–process of splitting a nucleus into two nuclei with smaller masses
Nuclear fission
–a large amount of energy is released
–Used in Nuclear reactors in power plants and submarines
Chain reaction – an ongoing series of Fission reactions
Nuclar Fusion
• Two nuclei with low masses are combined to form one nucleus of larger mass
• Can only happen when nuclei are moving fast enough to get close to each other
• Temperature in stars (millions of °C) are high enough for fusion to occur
• It is very difficult to contain the reaction. – it must happen at temperatures greater
than 108 oC, – no known material could contain it
without melting– some success has been achieved by
containing the reaction in a magnetic field
Dangers and Benefits of Nuclear Radiation
• Radioactive substances can be very useful , but when used carelessly, nuclear radiation can be extremely dangerous, even though we are exposed to some radiation everyday.
Dangers from Nuclear Radiation
• Background radiation• causing radiation sickness• causing genetic mutations
Benefits from Nuclear Radiation• smoke
detectors • radioactive
tracers in medicine– radioactive
material added to a substance so that its location can be detected later
Benefits to Nuclear Power• does not produce gaseous
pollutants that cause ozone depletion and acid rain
• Cheap to make electricity this way but expensive to build the power plant
• More energy in the known uranium reserves than in the known reserves of coal and oil
Dangers to Nuclear Power
• Radioactive products must be handled correctly
• Safety of the reactors • Equip with shielding • Storage of spent nuclear fuel