Radiation

What is Radiation?

Radioactivity (Radiation) is the release of high-energy particles and rays of energy from a substance as a resultof changes in the nuclei of its atoms.› When atoms radiate, another element can

be formed.› We call it radiation only when the energy

comes from the nucleus of the atom

What is Radiation?

Natural radiation exists all around us, from: radioactive substances in the Earth´s crust to cosmiv rays from outer space that bombard Earth. Trace amounts from these sources can be found in our food and water.

Being exposed to radioactive materials can be beneficial or harmful.

Beneficial (GOOD) Radiation Exposure

Harmful Radiation Exposure

-Medical imaging (iron-59)-Cancer treatment: radiation therapy-X-rays-Electricity generation

-Beta and Gamma radiatio can penetrate your skin and damage your cells.-High-energy particles and waves damage DNA in our cells.

The Electromagnetic Spectrum

Increasing Frequency

Decreasing Wavelength

• The the higher the frequencyof the radiation (i.e.the shorter the wavelength)= the more harmful the radiation is for you!

How Radiation Happens:1. An atom has an unstable nucleus2. The unstable nucleus splits apart3. Energy is released (we say ¨a nucleur

reaction¨occurs)4. The atom will contunue to radiate until

it becomes stable (often ending up as different atoms)

An element may only have certain isotopes that are radioactive. These are called radioisotopes.

Isotopes and Mass Number

Isotopes are different types if the same element, that have a different number of neutrons in the nucleus.

Isotopes have the same number of protons and electrons-so, they have the same atomic number and symbol BUT…

Different number of neutrons and therefore different mass number

Mass number refers to the #protons (atomic number) + #neutrons in an isotope

Isotopes are written by:1. Putting the mass number at the top

left.2. Putting the atomic numberat the

bottom left.Potassium has three isotopes:

Potassium isotopes

Three Types of Radiation

When atoms are unstable, they break apart to become new, more stable atoms, and release radiation. There are three types that can be released:1.Alpha 2.Beta 3.Gamma

Alpha Radiation ( )

Alpha radiation is a tream of alpha (helium) particles› Charge: +2 (2 protons)› Alpha particles are the same as a helium

atom. So we represent radiation:

Alpha Radiation

The release of alpha particles is called alpha radiation.

Alpha particles are slow and not very harmful. A sheet of paper will stop an alpha particle.

Example of Alpha Decay

Beta Radiation ( )

Beta radiation is a stream of beta (electron) particles, .› Charge: -1 (1 electron)› We represent radiation as:

› Beta particles are faster and more harmful than alpha. A sheet of metal foil (aluminum foil) will stop a beta particle.

Example of Beta Decay

Gamma Radiation ( ):

Gamma radiation is a ray of high energy.› No charge 0) and no mass (almost

no mass).› Gamma radiation is the highest

energy form of the electormagnetic radiation (most dangerous)

Gamma Radiation :

Gamma decay results from energy being released from a high-energy nucleus. It is shown by:

It takes thick blocks of lead or concrete to stop gamma rays.

Example of Gamma Decay

Gamma rays accompany the alpha decay og uranium-238.

You TRY Some!

How about some more???

* Means the nickle nucleus has extra energy!