What is radiation? :
What is radiation? Radiation is the emission of energy that travels in the form of either:
Waves --OR--
High-speed particles.
When we hear the word “radiation”, we often think of nuclear power plants, nuclear weapons, and radiation treatments for cancer.
Radiation is also involved in microwaves, radar, electrical power lines, cellular telephones, and sunshine.
Electromagnetic Spectrum :
Electromagnetic Spectrum
Two types of radiation :
Two types of radiation Non-ionizing radiation
Has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough energy to remove electrons.
Radio waves, microwaves, infrared light, visible light
Ionizing radiation
Has enough energy to break chemical bonds in molecules or remove electrons from atoms.
UV, X-Ray, Gamma ray, particle radiation
What types of ionizing radiation are there? :
What types of ionizing radiation are there? Alpha () particles
Beta () particles
Gamma () rays
. Credit: Wikipedia
What is radioactivity? :
What is radioactivity? Radioactivity is when an unstable nucleus of an atom gives off energy by radiation, in the form of particles or rays to become stable.
This process is also known as radioactive decay.
Examples of materials that contain radioactive atoms are strontium-90, plutonium-239, and iodine-131.
How is radioactivity measured? :
How is radioactivity measured? Radioactivity is measured by a Geiger counter, which measures ionizing radiation by counting the number of particles or rays it detects.
Geiger counters usually consist of three parts:
1) Geiger-Muller tube: A gas-filled tube whose gas ionizes upon contact with radioactive particles or rays.
2) Visual readout – a meter that keeps track of the number of radioactive particles being counted by the Geiger counter.
3) Audio readout – a meter that makes one “click” sound for each radioactive particle counted by the Geiger counter.
Hear what a Geiger counter sounds like:
http://www.geigercounters.com/Geiger.wav Credit: ThinkQuest
The Radioactivity iLab :
The Radioactivity iLab The lab equipment consists of:
1) A Geiger counter
2) A radioactive strontium-90 sample
You can set:
1) The distances in mm from the strontium-90 source, at which radiation can be measured (in units of “particle counts”)
2) The measurement time in seconds that each measurement of particle counts will last
3) The number of trials that will be conducted In this lab, you can study how the intensity of radiation changes over distance.