Brooke s High School Presentation Notes (90 minutes) Minimum Equipment Needed Alpha Meter (alternately you can use a alpha only source with the pancake) Pancake GM meter Fiestaware Plate Box with radiation signs containing Bananas Preparation: (1) Ask teacher student s current understanding of the atom, (2) set up overhead, (3) set up safe place for hotplate, (4) put bananas or No-Salt in the Ammo box, explain to the teacher about the Anti-C surprise I What Is Radiation, and what are the biological effects. 1) Introduce yourself. Describe what is a Health Physicist. 2) Ask class: When I say radiation, what thought come to mind? Write down the categories on the board, these usually include; Death, Mutations, Glowing things, Nuclear power, Atomic Bombs, & Cancer (if cancer is mentioned, ask what about cancer (i.e., identify both cure and cause). Hold up Comic books and ask if they think radiation does this 3) Ask class: So is Radiation good or bad? It works best to have them raise their hands to vote. Regardless of how the vote goes, tell them that you will ask the question again at the end of the class period, and you want them to see if they change their answer any. 4) Ask class: What is radiation? you will get a variety of answers, ask them if the following are forms of radiation: a. Light b. Heat c. Radio waves e. X-rays f. Gamma Rays Non-Ionizing Radiation Does not have enough energy to remove electrons from surrounding atoms d. Microwaves 5
5) Explain: These are all forms of EM radiation. What you as a Health Physicist primarily care about is Ionizing Radiation. The viewgraph shows the entire electromagnetic radiation spectrums. Show how the high energy side of the spectrum is considered Ionizing Radiation. There Are Lots Of Types Of Radiation 3 6) Ask: What does Ionizing mean? (Note this section needs to be tailored for the knowledge of the class). (Simplified Answer: It causes chemical changes, much like a sunburn causes chemical changes that turn your skin red.) For the advanced Students (who have had some chemistry/nuclear physics background). a. Use the Pizza slide. Pizza -> Ingredients -> Chemicals -> molecules - > Atoms -> Protons, neutrons, and electrons. b. Ask: What is an Ion? Review the ionization process. c. Explain: The effects of Ions in living tissue. 7) So now we know how Ionizing Radiation can hurt you. Is one ion going to hurt you? Atomic Structure All matter is made up of atoms Protons Neutrons Electrons Not all atoms are stable Unstable atoms are known as radioactive atoms 4 a. Explain: that our bodies have the truly wonderful ability to repair themselves. Radiation isn t the only thing that damages our cells. Natural chemicals in the food we eat and the Air we breath also cause damage. Heck, even when your brother or sister pinches your arm, thousands of cells are damaged or die. Our Bodies Are Resilient _ DNA damage is most important and can lead to cell malfunction or death. _ Our body has ~ 60 trillion cells» Each cell takes a hit about every 10 seconds, resulting in tens of millions of DNA breaks per cell each year.» BACKGROUND RADIATION causes only a very small fraction of these breaks (~ 5 DNA breaks per cell each year). _ Our bodies have a highly efficient DNA repair mechanisms 5
b. Every cell in our body takes a hit about every 10 seconds. In the course of this lecture everyone s body will have taken 10s of trillions (a million million) of hits 1. c. Ask: Should we worry?, Explain: Too much of anything can be bad for you, but our bodies can easily handle the usual assaults from our environment, our food, and even our brother (for the most part ). 8) Ask: Other than creating ions, what is another property of X-ray radiation? Answer: They can see through things! 9) Show: X-ray.. 10) Ask: What are X-rays good for X-ray machines are often used by doctors to see what is wrong with people s insides, without having to cut them open! 11) Ask: So, is X-ray radiation good or bad? II The Difference between Radiation and Radioactive Material 12) Ask: How many of you have had an X-ray? Select one of the students who raised their hand, and (looking wary) ask if they are now radioactive? The Projector trick: Turn the overhead projector around so the light shines toward the audience. Place your hand over the lens. Discuss: How some of the light actually gets through your hand (like an X- ray) Ask: where is the rest of the light going? Why, into my hand of course! Now since this is non ionizing radiation, it is 1 Trefil, J, How the Body Defends itself from the Risky Business of Living, Smithsonian, V26, number 9 (Dec 95).
depositing the energy in the form of heat. In fact your hand should be getting pretty warm! Turn the projector off, then remove your hand. Hold you hand up, Ask: Is my hand glowing? Use this analogy to explain why being exposed to radiation doesn t make you radioactive. 13) Ask: So where does radiation come from? Some radiation comes from machines, like X-ray machines. This kind of radiation can be turned on and off like a light bulb. Some radiation comes from radioactive material, like Co-60, Sr-90, Uranium and Plutonium. The nucleus of these atoms are unstable and they will transform into other, more stable atoms, and give off a little energy in the process. The energy that they give off is in the form of radiation!. 14) Half-life: Describe the concept of half life. III The types of Radiation (α, β, & γ) 15) Describe the different types of radiation. Be sure to note that Alpha & Beta are charged particles. Ionizing Radiation - can deposit energy in neighboring atoms resulting in the removal of electrons. The FiestaWare Plate Demonstration. Give the plate to a student, ask them if it feels warm, appears to be glowing, or is making any noise. Take the plate back and describe how it s lovely Orange color comes from Uranium in the glaze. Since uranium is radioactive (it has a half life of 4.5 billion yrs and has been around since the Earth was formed) 6 {Note: Item 16 & 17 below requires an alpha only meter or a pancake meter with an alpha only source} 16) The Alpha Demo: Inform the students the Alpha Radiation is the most energetic kind, then ask them to guess how far the alpha radiation will travel in air. Describe the function of the Alpha Meter, then have a volunteer slowly lower the probe to the plate.
17) Alpha Shielding Demo: After explaining why the Alphas only travel a few inches in air, Ask the Students How much paper do they think is required to block alphas? Demonstrate, then discuss how alphas are even blocked by our dead layer of skin! 18) Introduction to background Radiation: hold up and describe the Pancake GM Meter. Turn the meter on. Act surprised when it begins clicking with background. Ask the students what is going on? Explain about background (cosmic and terrestrial) radiation. 19) The Beta Demo: Remind the students about Beta radiation. Ask the students how far they think the beta radiation will travel in air. Get a volunteer to hold the plate and another to hold the meter, have them walk toward each other until the class hears counts above background. Inform the class that Beta s can travel around 12 feet in air. 20) The Beta Shielding Demo: Ask the students what they think it will take to block the Beta Radiation? Start with a single piece of paper and move onto overheads and thicker plastic. Explain that the clicks above background that they still hear with the plastic shield in place are actually from gamma rays, which are far more penetrating. IV Background Radiation and Commercial Uses of Radiation: 21) Ask: So where does radiation come from and how is it used? a. Reaffirm background radiation, discuss the different sources, including ingestion (uranium, potassium, etc..) b. Medical uses of radiation (diagnostic & treatment) c. Commercial Uses: Smoke Detectors, Radioluminescent, etc. d. Industrial Uses (Radiography, Nuclear power, sterilization) Background and Manufactured Radiation In the U.S. Contributes 360 mrem per Year cosmic - 28 diet - 40 Nuclear Power radon - 200 Uses of Radiation Food sterilization terrestrial - 28 Industrial and Medical Uses 13 Consumer products 15
e. Nuclear weapons. 22) Ask: So is radiation Good or Bad? Hopefully the students answers should reflect what has been discussed. Emphasize that radiation isn t good or bad, but how it is used can help us, or hurt us. V Contamination: 23) Ask: If alpha radiation can t even get past the dead layer of skin how can it hurt us? Discuss: There is no protection inside your body, and all of that energy is deposited into living tissue. 24) Hold Up Some Anti-Contamination clothing (anti-cs), Ask: What are these, will they protect you from radiation? Place the Anti-Cs over the plate, demonstrate how the radiation goes right through them. Ask: what good are they? Discuss: The concept of contamination, and why it is important that we keep it outside of the body. Not only for alpha radiation, but for all forms of radioactive material. Discuss how radioactive material inside your body continues to expose you and you can t just walk away. 25) Ask for 2 volunteers to dress out in anti-cs. (if there is a 2 nd HP, have them dress the students out, stash a radium dial watch or lantern mantel in the pant cuff). 26) Bring out the source Box, Discuss how you knew there would be some properly prepared people to help you open the box, so as long as they were dressed out. Demonstrate how hard it is to understand what people are saying while wearing a respirator. Make everybody move back and have the students open the ammo box. 27) Ask: Are Bananas (or No Salt) radioactive? Answer: YES! They contains potassium which is naturally radioactive. Hold up the meter to the banana, demonstrate that there is not much radiation there. 28) Ask: So should you stop eating bananas? Answer: heck no! In addition to natural radiation from space and
the ground, there is little bit of natural radioactive material in all the food we eat and the water we drink. Your body can handle a little radiation, but I doubt you would be around for long if you stopped eating and drinking! 29) Ask: So what do you say if somebody says to you: WATCH OUT DUDE! THAT STUFF IS RADIOACTIVE! Answer: Everything is radioactive, You should ask if it is radioactive like a banana or like a nuclear reactor. 30) Now that the operation banana is complete, demonstrate how we would survey the students before they remove the anti-cs. (discover the watch/lantern mantel). V TLD Demo (optional): Discuss TLDs and remind them about the HOT plate. Remember, Have Fun! Please e-mail me if you have any comments or suggestions! - Brooke Buddemeier - brooke2@llnl.gov