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Uses and Effects of Radiation

Radioactive substances are everywhere around us (even in our bodies)!

Natural Background Radiation

• All radioactive substances that occur naturally in organic matter

• Includes radiation from soil, water, atmosphere, space, etc..

• Generally harmless to living things

Ionizing Radiation

• All radiation that has enough energy (high frequency, short wavelength) to cause damage to living tissues.

• Has enough energy to knock electrons out of atoms (creating ions).

• Potentially harmful to all cells, but most dangerous to cells that are developing or multiplying, such as reproductive cells, blood forming cells in the bone marrow, intestinal or fetal cells.

• Dangers include radiation sickness (vomiting, diarrhea, nausea, appetite loss), cancer (cells divide uncontrollably), and mutations (miscoded genetic material).

USES of Radiation ( Use the information in the power point to complete the chart:

|Household uses |Medical uses |Industrial uses |Scientific uses |Recreational uses |

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How can you protect yourself from radiation?

1. Distance – stay away from sources

2. Time – limit the length of exposure

3. Shielding – protective clothing or chemicals (lead vests, sunscreen)

Geiger Counter – a device used to measure radioactivity by measuring levels of ionizing radiation.

Radiation Review:

1. EM spectrum: What is it? What is it based on? Give some examples.

2. List the three types of Radioactive decay. How can you recognize these three types of decay? Which of these decay types undergo “nuclear transmutation”?

3. SOLVING NUCLEAR EQUATIONS:

[pic]( [pic] + ____________ Type of decay: ______________

[pic] ( [pic] + ____________ Type of decay: ______________

[pic]( ___________ + γ Type of decay: ______________

[pic]( _____________ + [pic] Type of decay: ______________

[pic]( ____________ + [pic] Type of decay: ______________

4. HALF LIFE GRAPHS:

a. What is a half life?

b. What makes something “radioactive”?

c. What happens to the ACTIVITY of a sample as it gets smaller?

d. Use the graph to answer the following questions:

i. What is the half life?

ii. How many daughter atoms are there after one half life? After two half lives?

iii. How many daughter atoms are there after 175 seconds?

iv. What percentage of radioactive parent nuclei are remaining after 325 seconds?

v. If you have a sample with 20% parent and 80% daughter, how old is the sample (how long has it been decaying)?

5. RADIOMETRIC DATING: (using half lives to determine the age of a sample)

a. A 100 gram sample of radioactive carbon-14 has a half life of 5730 years. If only half of that sample remains, how old is the sample?

b. If there is 12.5% carbon-14 (unstable parent) left in a sample, how many half lives have passed? How old is the sample?

c. If you started with 16 grams of carbon-14 in a radioactive sample, and now there is only one gram left, how many half lives have passed? How old is the sample?

Teacher Notes: Applications of Radiation

The list below is not comprehensive, but it gives a few examples of radiation at use. For more in depth information the following website is very useful.



Medicine

1. X-rays –used to take pictures of bones and teeth. As X-rays pass through the patient they are absorbed by the dense bones more so than by the flesh. This causes the bones to appear lighter on the radiograph.

2. Gamma Radiation – can be used to take pictures similarly to an X-ray.

3. Radioactive Isotopes – injected into blood stream, or ingested by patients so that doctors are able to follow their paths through the body

4. Thyroid treatment – an iodine isotope in injected into the blood and releases beta emissions in the thyroid to destroy some tissue and reduce over activity.

5. Cancer treatment

i) Radiation (usually x-rays or gamma rays) is aimed at the cancerous growth in an attempt to destroy cancerous cells.

ii) Radioactive strontium is injected into the blood and emits beta radiation that helps to destroy cancerous cells.

Both of these treatments also destroy healthy cells and often result in the patient becoming quite sick.

6. Many other uses – many diagnostic tests involve radiation and many new radiation treatments/therapies are being developed.

At Home

1. Microwaves

2. Remote control (infrared and microwaves)

3. Smoke detectors (emit tiny amounts of alpha and gamma radiation)

4. Cell phones (radio waves)

Industrial

1. Detecting material flaws

2. X-ray at airports

3. Food irradiation to kill bacteria

4. Nuclear power plants

Scientific

1. Radiocarbon dating

2. Fission reactors

3. Particle accelerators

4. Electron microscopes

Recreational

1. Tanning machines

2. Black lights

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