RadiationRadiation: The process of emitting energy in the form of waves or particles.

Where does radiation come from?Radiation is generally produced when particles decay.

A large contribution of the radiationon earth is from the sun (solar) or from radioactive isotopes of the terrestrial elements (from land).

Radiation is going through you atthis very moment!

What do we mean by Radioactive decay?

Radioactive decay is the process in which…

An unstable nucleus releases energy to become more stable!

Radioactive decay can cause 3 types of radiation!

RadioactivityThree types of radiation were known:

1)Alpha particles ()

2)Beta particles ()

3)Gamma-rays ()

Three types of radiation were known:

1)Alpha particles ()

2)Beta particles ()

3)Gamma-rays ()

• An alpha particle is formed when the nucleus of an atom becomes unstable. The nucleus breaks apart and releases a part of it in order to become stable. This piece that is released consists of two protons and two neutrons. This is the alpha particle!

• It has a positive 2 charge!

• All alpha particles are the same as a helium nucleus (2 protons and 2 neutrons).

• The alpha particle is the least penetrating type of radiation.

Radiation Types - Alpha

• A beta particle is formed when the neutron to proton ratio is too great in the nucleus and causes instability. Neutrons are turned into protons and electrons. The electron is then emitted from the nucleus at high speeds! This electron is the beta particle.

• The beta particle can be positively or negatively charged

Radiation Types - Beta

• Gamma particles are formed when the nucleus of an atom has too high of an energy level. The nucleus falls down to lower it’s energy state and emits a high energy photon. This photon is a gamma particle.

• An x or gamma ray• Has no weight• Has no charge

• Consists of electromagnetic radiation.

• Gamma Rays are the most penetrating type of radiation

Radiation Types – Gamma Ray

REVIEW: How far can these particles penetrate?

Alpha ParticlesStopped by a sheet of paper

Beta ParticlesStopped by a layer of clothingor less than an inch of a substance (e.g. plastic)

Gamma RaysStopped by inches to feet of concreteor less than an inch of lead

RadiationSource

Nuclear Fission Nuclear Fission and Fusionand Fusion

Nuclear power

•Power can be obtained two ways:

1.Fission-- Splitting atoms2.Fusion-- Joining atoms

Nuclear Fission

• A nucleus splits because it is too heavy, and it forms a more stable nuclei.

• The mass of the products is less than the mass of the reactants.

• It produces toxic waste!

• New elements are formed!

Nuclear Fission & POWER

• Fission is used in nuclear power

plants to form energy!

• 17% of the world’s energy comes from

nuclear power!

Fusion• Light-mass nuclei combine to form a heavier,

more stable nucleus.

• More energetic than fission reactions

• The sun is the source of energy for fusion reaction

• Fusion, like fission, also produces new elements!

• Helium is its major product! Helium production in great amounts is referred to as the H-Bomb!

The most destructive force on the planet

H-bombs