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Radioactivity Radioactivity Chapter 9 Chapter 9 Nuclear Changes Nuclear Changes

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Page 1: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

RadioactivityRadioactivity

Chapter 9Chapter 9

Nuclear ChangesNuclear Changes

Page 2: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

RadioactivityRadioactivity

Radioactive materials Radioactive materials have unstable nuclei.have unstable nuclei.

They emit They emit particles/energy to particles/energy to become stable. become stable.

Isotopes are generally Isotopes are generally radioactive. Why do radioactive. Why do you think that is?you think that is?

Page 3: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

Four Different Types of Four Different Types of RadioactivityRadioactivity AlphaAlpha

Protons and Neutrons Protons and Neutrons are emittedare emitted

BetaBeta 1 electron is emitted1 electron is emitted

GammaGamma Light is emittedLight is emitted

NeutronNeutron Neutrons are emittedNeutrons are emitted

Page 4: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

So Why Is It Dangerous?So Why Is It Dangerous? It’s not ALWAYS It’s not ALWAYS

dangerous, but most of dangerous, but most of the time it is.the time it is.

The energy/particles that The energy/particles that are emitted travel are emitted travel through the air and hit through the air and hit the atoms it meets. This the atoms it meets. This disturbs the atoms.disturbs the atoms.

Do you think you want Do you think you want disturbed atoms in your disturbed atoms in your body?body?

Page 5: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

How Do We Prevent too How Do We Prevent too much Radiation Exposure??much Radiation Exposure?? Shielding!Shielding! Shielding is the materials that Shielding is the materials that

are between the radioactive are between the radioactive source and the detector or source and the detector or person.person.

The purpose of shielding is to The purpose of shielding is to reduce the amount of radiation reduce the amount of radiation that one person or object that one person or object receives.receives.

Page 6: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

ShieldingShielding

Alpha particlesAlpha particlesStopped by paper or the skinStopped by paper or the skinPresent little or no hazard external to Present little or no hazard external to

bodybodyInternal hazard (if it gets in the body)Internal hazard (if it gets in the body)

Beta particlesBeta particlesStopped by light metals (aluminium) Stopped by light metals (aluminium)

and plasticsand plasticsInternal and external hazardInternal and external hazard

Page 7: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

ShieldingShielding Gamma raysGamma rays

Stopped by very dense materials Stopped by very dense materials (lead, concrete)(lead, concrete)

Easily pass through the human bodyEasily pass through the human body Internal and external hazardInternal and external hazard

NeutronsNeutronsStopped by materials containing Stopped by materials containing

hydrogen atoms, such as water, hydrogen atoms, such as water, polyethylene, and concretepolyethylene, and concrete

Internal and external hazardInternal and external hazard

Page 8: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

Shielding: Alphas, Betas, Shielding: Alphas, Betas, Gammas and NeutronsGammas and Neutrons

Page 9: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

Where Does the Where Does the Radiation Come From?Radiation Come From?

The radiation you receive can be either The radiation you receive can be either Natural or Man-madeNatural or Man-made

Page 10: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

Sources of Radiation: Sources of Radiation: Natural Natural Cosmic: Cosmic:

Sun Sun

Terrestrial: sources in the earth’s Terrestrial: sources in the earth’s crustcrust

Soil (radon)Soil (radon)WaterWaterVegetation (Bananas)Vegetation (Bananas)

Internal: sources in the human Internal: sources in the human bodybody

Potassium-40Potassium-40Carbon-14Carbon-14Lead-210Lead-210

Page 11: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

Sources of Radiation: Sources of Radiation: Man-madeMan-made MedicalMedical

X-raysX-rays Cancer treatmentsCancer treatments

CommercialCommercial TVTV Lantern mantelsLantern mantels Smoke detectorsSmoke detectors Fuel cycle (nuclear power)Fuel cycle (nuclear power)

Page 12: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

Determining Your Determining Your Personal Annual Personal Annual Radiation DoseRadiation Dose

Page 13: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

Average Annual Dose to Average Annual Dose to Ionizing RadiationIonizing Radiation

All living creatures constantly receive a All living creatures constantly receive a certain amount of radiation from outer certain amount of radiation from outer space, the soil, food we ingest or even space, the soil, food we ingest or even the air we breathe. the air we breathe.

The sources of radiation fall under two The sources of radiation fall under two categories: natural and man-made, categories: natural and man-made, collectively known as collectively known as background background radiationradiation. .

The The averageaverage annual personal dose from annual personal dose from background radiation is approximately background radiation is approximately 350350 mRem/year. mRem/year.

Page 14: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

What To DoWhat To Do In this activity, you will estimate your In this activity, you will estimate your

personal annual radiation dose using the personal annual radiation dose using the Background Information Worksheet provided. Background Information Worksheet provided. When doing this activity, keep in mind that When doing this activity, keep in mind that the amount of the amount of terrestrial radiation varies in different parts terrestrial radiation varies in different parts

of the world due to different concentrations of the world due to different concentrations of uranium and thorium in soil. of uranium and thorium in soil.

cosmic radiation varies in different parts of cosmic radiation varies in different parts of the world due to differences in elevation the world due to differences in elevation and to the effects of the earth’s magnetic and to the effects of the earth’s magnetic field.field.

Page 15: Radioactivity Chapter 9 Nuclear Changes. Radioactivity  Radioactive materials have unstable nuclei.  They emit particles/energy to become stable

ProcedureProcedure Complete the worksheet and tally the total.Complete the worksheet and tally the total. For central Ohio, the average elevation is about 825 For central Ohio, the average elevation is about 825

feet above sea levelfeet above sea level approximate dose is 28 mRem/year from cosmic radiation.approximate dose is 28 mRem/year from cosmic radiation.

For every hour in an airplane, you receive 0.5 mRem For every hour in an airplane, you receive 0.5 mRem Make sure to use 30 mRem/year for the second Make sure to use 30 mRem/year for the second

entry.entry. In central Ohio, we are not within 50 miles of a In central Ohio, we are not within 50 miles of a

power plant. However in southern Ohio, there are power plant. However in southern Ohio, there are many coal plants along Ohio River.many coal plants along Ohio River.