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