Radiation

Radiation When you see or hear this word what do you think about? What do you think it means? Share your thoughts with me by writing on the post it what you think about when you see this word. Do not put your name on the post it.

Radiation is all around us It comes from the Earth and from outer space. Many forms of radiation are invisible -- we can't feel it, see it, taste it, or smell it. Yet, it can be detected and measured when present.

Everyday we are exposed to Radiation Called natural or background radiation. Natural radiation accounts for about half of our total annual exposure. Man-made sources — mostly medical procedures make up the other 50%.

Natural or Background Radiation Radon, a radioactive gas from uranium found in soil dispersed in the air; Today Show - Radon Gas Radioactive Potassium in our food and water; Uranium, Radium, and Thorium in the Earth's crust; And from Cosmic Rays and the Sun.

Man-made radiation sources tobacco, television, medical x-rays, smoke detectors, lantern mantles, nuclear medicine, and building materials. Click Image to calculate your radiation exposure according to the American Nuclear Society.

Radiation Damage Mutate hemoglobin Mutate cells, lose function Destroy immune system Burn skin, destroy bone

Radioactive Tracer What is a radioactive tracer? - short lived isotope that can be observed with a sensitive detector

Radioactive Tracer How are they used? - Agriculture – measure water flow - Medicine – locate tumors - Medical research – trace drug paths thru body - Geology – trace underground water flow

Radioisotope tracers in Medicine

Measuring Radiation A Geiger counter has a negatively charged Cu tube with a positively charged wire running through it.

Measuring Radiation The tube is filled with gas at low pressure. Radiation knocks electrons off the gas which are attracted to the wire producing a current.

Measuring Radiation An amplifier strengthens the current producing a clicking sound or a flashing light. The number of clicks or flashes per second tell how strong the radiation is.

Watch and Learn Everyday Radiation Clip Radon Radiation Facts About Radiation Interactive Sources of Radiation Show Geiger Counter Demos “Whys Guy” shows some everyday radioactive materials. 4:24 min Fiesta Ware Info

But what is radiation? Radioactive materials are composed of atoms that are unstable. An unstable atom gives off its excess energy until it becomes stable. The energy emitted is radiation.

Know this… While there are several different forms of radiation, we're going to concentrate on just three that result from the decay of radioactive isotopes: alpha, beta, gamma.

Let’s Review What You Already Know What are isotopes? Element that have the same number of protons, but a different number of neutrons. Chemist call isotopes Nuclide What are radioactive isotopes? Isotopes that are radioactive.

Let’s Review A radioactive isotope emits particles and energy. When the process occurs, the radioactive isotope goes through nuclear decay producing… An entirely new element or Another isotope of same element

Nuclear Radiation Nuclear radiation = matter and energy released when a radioactive isotope decays

What happens when an element undergoes radioactive decay? During radioactive decay an unstable nuclei of an isotope emits particles and releases energy, to become a stable isotope. “NUCLEAR” To radiate means “to give off”

Non – Ionizing Radiation Radiation that has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough to move electrons. We take advantage of the properties of non-ionizing radiation for common tasks: microwave radiation– telecommunications and heating food infrared radiation --infrared lamps to keep food warm in restaurants radio waves-- broadcasting My electrons vibrate!

Electromagnetic Radiation Energy given off by an atom due to an acceleration of the atoms electrons

Ionizing Radiation Radiation that falls within the ionizing radiation" range has enough energy to remove tightly bound electrons from atoms, thus creating ions. This is the type of radiation that people usually think of as 'radiation.' We take advantage of its properties to generate electric power, to kill cancer cells, and in many manufacturing processes. You make my electrons leave!

Nuclear Radiation A release of energy and particles from the nucleus of an atom

The energy of the radiation shown on the spectrum below increases from left to right as the frequency rises. Type of Radiation Effects Source

Three types of Ionizing Radiation Alpha Particles Beta Particles Gamma Rays

Alpha Particles (think charged particle Helium) What is it? Helium Nucleus Energy – Low Energy Speed – Varies Range – 5 m (15ft.) in air, can be stopped by paper or skin Shielding required – None Biological Hazard – None unless in large quantities- Least Harmful Atomic Changes Mass number (decrease): -4 (2p +2n) Atomic number: -2 (protons)

The “emission” of a helium nucleus – 2 protons and 2 neutrons

Alpha Decay

Alpha Decay

Beta Particle (think electron and transmutation) What is it? High Speed Electron- A neutron splits into a proton and an electron Energy – Varies Speed – Varies Range – 5 m in air, can be stopped by clothes or wood Shielding required – moderate clothing Biological Hazard – Superficial Skin injury Atomic Changes Mass number: no change Atomic number: +1 (protons)

Beta Decay

Beta Decay

Beta Decay

A neutron in the nucleus of the atom becomes a proton and emits an electron. Note: a neutron is not made of a proton and an electron.

Gamma Rays (think wave or high energy light) What is it? Electromagnetic Energy – High Energy Radiation- NOT MADE of MATTER Energy – Varies Speed – Travels at the speed of Light Range – 500 m in air, can be stopped by lead or many feet of concrete Shielding required – dense material such as concrete, steel plate, earth Biological Hazard – Dangerous to living things Atomic Changes No change A Gamma Ray (ˠ) is produced

Gamma Rays No Atomic Changes

Gamma Rays

Don’t worry…unless your name is Bruce.

Review

Nuclear Radiation

Alpha, Beta, and Gamma. Which objects can travel through video. :58 min

Electromagnetic Spectrum

Let’s Practice

Let’s Practice

Let’s Practice

Let’s Practice

Let’s Practice

Challenge with a partner Use Atomic notation like the problems from the previous slides and create an alpha decay with the nuclide (isotope) of your choice

Challenge with a partner Use Atomic notation like the problems from the previous slides and create an beta decay with the nuclide (isotope) of your choice