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Radioactivity. Radiation When you see or hear this word what do you think about? What do you think...

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Radioactivity
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Page 2: Radioactivity. 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.

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.

Page 3: Radioactivity. 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.

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.

Page 4: Radioactivity. 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.

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%.

Page 5: Radioactivity. 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.

Natural or Background Radiation

• Radon, a radioactive gas from uranium found in soil dispersed in the air;

• Radioactive Potassium in our food and water; • Uranium, Radium, and Thorium in the Earth's crust;

• And from Cosmic Rays and the Sun.

Page 6: Radioactivity. 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.

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.

Page 8: Radioactivity. 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.

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.

Page 9: Radioactivity. 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.

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.

Page 10: Radioactivity. 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.

Let’s Review What You Already Know

• What are isotopes?

• Element that have the same number of protons, but a different number of neutrons.

• What are radioactive isotopes?

• Isotopes that are radioactive.

Page 11: Radioactivity. 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.

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

Page 12: Radioactivity. 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.

Nuclear Radiation

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

Page 13: Radioactivity. 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.

Three types of Radiation

1. Alpha Particles

2. Beta Particles

3. Gamma Rays

Page 14: Radioactivity. 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.

Alpha Particles (think charged particle Helium)

• Made of 2 protons and 2 neutrons

• Positively charged (+2)• Emitted from unstable Istotopes • Largest type of nuclear

radiation• Slow speed and low

penetrating distance (1 to 2 inches in air)

• Can be stopped by a sheet of paper or body’s outer layer of skin

• Least harmful type of nuclear radiation

Click Here Americium, in a cloud chamber

Page 15: Radioactivity. 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.

Beta Particle (think electron)

• Made up of faster moving and lighter electrons

• Negatively charged• Smaller than alpha

particles• Can travel through 10 ft.

of air pass through a sheet of paper, but can be stopped by aluminum or wood

• While clothing will stop most beta particles, they can penetrate the live layers of skin tissue.

Page 16: Radioactivity. 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.

Gamma Rays (think wave or high energy light)

• Not made of matter• No charge• No Mass and Travels at the Speed of Light• Electromagnetic Wave with the most energy• Carry the most energy and the most harmful

radiation. Harmful to internal and external tissue.

• Can only be stopped with thick layer of lead or concrete

Page 17: Radioactivity. 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.

Don’t worry…unless your name is Bruce.

Page 18: Radioactivity. 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.

Gamma Rays

Page 19: Radioactivity. 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.

Nuclear Radiation

Page 20: Radioactivity. 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.

Electromagnetic Spectrum

Page 21: Radioactivity. 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.

Measuring Radiation

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

Page 22: Radioactivity. 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.

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.

Page 23: Radioactivity. 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.

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.

Page 24: Radioactivity. 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.

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

• “Whys Guy” shows some everyday radioactive materials. 4:24 min


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