P3 Radioactive materials Route map Over the next 12 lessons you will study : Friday 21 October 2011 P3.1 Energy patterns P3.2 radiation all around us P3.3 Living with Radon P3.4 Radiation and health End of module test P3.5 Radiation and exposure P3.6 Changes inside the atom P3.7 Nuclear power P3.8 Generating electricity from nuclear power P3.9 Nuclear waste P3.10 Nuclear waste disposal is it safe ? P3.11 Energy of the future P3.12 The energy debate
P3.1 Energy patterns Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand the difference between primary and secondary sources of energy </li></ul><ul><li>Understand the importance of energy efficient and its use around the Globe </li></ul><ul><li>Understand how energy changes day to day in the UK </li></ul>We will focus on. Friday 21 October 2011 First activity: Think of a typical 24 hour day. Draw a line along your book showing midnight to midnight. Showing energy consumption in joules per second on the y (vertical axis) show how you think the demand for energy varies over this 24 hour period. ? Literacy: Energy, primary source, secondary source, demand, kilojoules, energy source, energy supply and generation and efficiency, . Numeracy: In the UK we use about 5 to 6 kilowatt hours of energy per person per day. In under developed countries energy consumption can fall as low as each person using a 0.1 kilowatt hour per day. PLTS Independent enquirers Creative thinkers Reflective learners We will focus on Team workers Effective participators Self managers
P3.1 Energy patterns Decide whether the following statements are true or false: Introduction: We all use primary (gas, coal oil) and secondary energy (electricity) sources fro everyday activities like boiling a kettle and driving a car. In UK power stations, the energy trapped in fossils fuels like coal and oil is released during their combustion. This energy is used to produce steam, which drives huge turbine generators. Electrical energy produced is delivered across the nation by the national grid. Demand for electricity can depends on the season and even the time of day. Peak demand is around 6 to 8 p.m when most families are at home preparing their main meal of the day. Extension questions: 1: Explain why most of the electrical energy we use comes from fossil fuel powers stations ? 2: Fossil fuel power stations emit two polluting gases: carbon dioxide and sulphur dioxide. What effects on the environment do these two gases have ? 3: Explain ho a wind turbine generates electricity and why are most wind farms placed out at sea ? 4: Give three advantages and disadvantages to using fossil fuel power station to generate the nation’s electrical energy ? Know this: a: Know that chemical energy trapped in coal, oil or gas is converted into electrical energy inside a power station. b: Know that renewable sources of energy like wind and tidal are now being used to generate electricity. Friday 21 October 2011
P3.1 a Look at the photograph and information and answer all the questions: When running we can use up to 300 joules or 0.3 kJ per second...work out how many joules we would use when a) we did a 10 second run and b) a 2 minute run ? If there are 1000 joules in 1 kilojoule (kJ)...work out how many joules there are in a) 2.2 kJ b) 10 kJ c) 25.4 kJ and d) 65 kJ ? Explain why you will use more joules per second when you are running when compared to when you are walking ? Energy types Sound Heat Electrical Light Kinetic Elastic Chemical Gravitational potential energy Energy cannot be destroyed or created, it can only be transformed from one type to another using a device. Energy is measured in units called joules. Using joules allows you to compare how much energy in joules, something uses per second (e.g. a light bulb) or contains (e.g. chocolate bar.) The joule is a very small unit of energy. Running 300 JS -1 Walking 175 JS -1 Key concepts
P3.1 b Look at the photograph and information and answer all the questions: The world will need greatly increased energy supply in the next 20 years, especially cleanly-generated electricity. Electricity demand is increasing much more rapidly than overall energy use and is likely to almost double from 2004 to 2030. Nuclear power provides about 15% of the world's electricity, almost 24% of electricity in OECD countries, and 34% in the EU. Its use is increasing. Look at the map opposite left, it show in red and dark red the biggest users of energy. Which countries are the biggest users of energy ? Explain why the USA are the biggest users of energy ? Look at the graph opposite left a) explain how energy demand changes over a 24 hr period and b) when and why does peak demand happen ? Key concepts
P3.1 c Look at the photograph and information and answer all the questions: A device like a laptop or a television transforms electrical energy into other forms of energy. Some of the energy transformed is not useful and dissipates usually as heat to the surroundings. A filament light bulb converts electrical energy into heat and light energy, with only the light energy being useful. Work out the energy efficient of the filament light bulb if for every 150 joules of electrical energy supplied, only 30 joules of light energy is produced ? Energy efficient light bulbs create very little heat, therefore they waste very little energy. Explain why the government is right to ban the sale of filament light bulbs from 2011 ? Using a diagram show the energy transfers when using a) a hair dryer b) a toaster c) a television d) an electric fire and e) a laptop ? 150 joules of electrical energy 120 joules of heat energy 30 joules of light energy Input energy Output energy Energy efficiency of a filament electric light bulb Energy efficiency of a filament electric light bulb Sankey diagram Key concepts
P3.1 Plenary Lesson summary: gases rise energy costs Friday 21 October 2011 The filament light bulb is very energy efficient only using a small fraction of the input energy to produce light. The remaining energy is lost to the surroundings as heat energy. The energy efficient light bulb waste only 10% pf the energy because unlike filament light bulbs it produces virtually no heat. How Science Works: Research into what are the main sources of background radiation. Look into the health effects of radiation and how do we measure the dose of radiation Preparing for the next lesson: Global _______ demands are expected to _______ by over 50% between 2010 and 2030. This will lead to supply pressures, increasing energy _____ and greater levels of greenhouse ________ entering our atmosphere Decide whether the following statements are true or false : False True 3: A primary energy source is coal, a secondary energy source is electricity ? False True 2: The national grid supplies electrical energy to all UK homes ? False True 1: Peak energy demand occurs at midnight during 24 hour cycle ?
P3.2 Radiation all around Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand that we are all subject to background radiation </li></ul><ul><li>Understand that in certain areas in the UK radioactive radon gas seeps form the bedrock posing a radiation risk to those who live in radon areas </li></ul>We will focus on. Friday 21 October 2011 First activity: List three jobs where an individual may be exposed to higher levels of radiation than an average employee. Explain why their total dosage is more ? Literacy: Radiation, dosage, background radiation, total dosage, risk, mSv Radon gas, health effects, cancer and risk.. Numeracy: The annual UK dose for a person who has a typical job is around 2.50 to 3.0 mSv. About half of this comes form just one source here in the UK, radon gas. PLTS Independent enquirers Creative thinkers Reflective learners We will focus on Team workers Effective participators Self managers
Extension questions: 1: Explain why you cannot avoid background sources of radiation ? 2: In what units is radiation measured ? 3: If our average expose to background radiation is about 2.5 mSV, would an airplane pilots be lower or higher…explain your answer ? 4: A long haul flight exposes you to 0.1 mSV, estimate a pilots total exposure if he does 200 long haul flight a year ? 5: Explain why there is no such things as a safe amount of radioactivity ? Know this: a: Know that we are all exposed to radiation form background sources. b: Know that in certain areas of the UK Radon gas increase our expose to radioactivity. Friday 21 October 2011 <ul><li>Introduction: </li></ul><ul><li>Background radiation is constantly present in the environment and is emitted from a variety of natural and artificial sources. Primary contributions come from: </li></ul><ul><li>Sources in the earth. These include sources in food and water, </li></ul><ul><li>Sources from space, in the form of cosmic rays; </li></ul><ul><li>Sources in the atmosphere. One significant contribution comes from the radon gas that is released from the Earth's crust </li></ul><ul><li>Naturally occurring sources are responsible for the vast majority of radiation exposure. However, about 3% of background radiation comes from man-made sources such as: medicine, power stations and luminous watch dials. </li></ul>P3.2 Radiation all around
P3.2 a Look at the photograph and information and answer all the questions: Radiation exposure over your lifetime increase the probability of cancers, tumours and birth defects. There is no such thing as a safe dose and exposure to just one radon atom can change a cell’s DNA which can then develop into a tumour. Some jobs like those in nuclear medicine and power have a higher risk when compared to other jobs like teaching. Which is the largest contributor of background radiation ? List three jobs which may increase your exposure to radioactivity ? How can you protect workers who work in an environment which exposes then to radioactive materials ? <ul><li>Background radiation </li></ul><ul><li>Radon gas (50%) </li></ul><ul><li>Food and water (12%) </li></ul><ul><li>Cosmic rays (10%) </li></ul><ul><li>Other sources </li></ul><ul><li>Nuclear power <1% </li></ul>Key concepts
P3.2 b Look at the photograph and information and answer all the questions: There is no such things as a safe dose form radioactive source. Just one radon might cause a cell to become cancerous. In 2006, Alexander Litvinenko, a former Russian spy died in London hospital after ingesting a highly toxic radioactive isotope in a cup of bought in a bar of a five star London hotel, The substance, polonium 210 is not the kind of weapon that any kind of amateur could construct and was powerful enough to kill Litvinenko with a few days of drinking the poison tea. To date no one has been charged for his murder. A does of 1000mSv will kill 4 out 100 people. Estimate the dosage that Litnenko received through drinking the contaminated tea ? List three symptoms of radiation sickness ? Key concepts
P3.2 Plenary Lesson summary: gas around sources exposure Friday 21 October 2011 There is no such thing as a safe does, just one radioactive atom could change your cell’s DNA and therefore cause cancer. There are several steps you can take to reduce your risk: Don’t fly or work in nuclear medicine or power stations. For zero risk, live deep underground surrounded by several metres of thick lead and screen you food and air that you breath ensuring zero radiation ! How Science Works: Research into our exposure to radon gas and how architects and designers can protect homes for radon gas build up inside the rooms that we live in. Preparing for the next lesson: Background radiation is all ______ us. Most of the background radiation comes from natural ______. Radon ____ is by far the largest contributor accounting for about 50% of our daily _______. Although most people would not like to live near a nuclear power station, nuclear discharges account for only about 0.1% of our yearly dose . Decide whether the following statements are true or false : False True 3: There is no such things as a safe dose of radiation ? False True 2: Cosmic rays account for about 10% of our yearly dose ? False True 1: The food we eat can contain radioactive materials ?
P3.3 Living with radon Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand that up to 50% of the background radiation that we are exposed to comes from radon gas </li></ul><ul><li>Understand that home or houses built in areas with radon gas have to be designed to prevent the build up of radon gas in its living areas </li></ul>We will focus on. Friday 21 October 2011 First activity: About 2500 to 3000 deaths per year are cause by lung cancers as a result of radon gas here in the UK. Deaths from skin cancer caused by UV light are about 1500 per year. Do you think the government provide enough information about the risks of living in a high radon gas area ? Literacy: Radon, radioactivity background sources, alpha radiation, ionising radiation, irradiation, contamination, inhalation, exposure risk and protection Numeracy: In the UK nearly 500,000 homes are affected by radon gas. They are designed to safely prevent build up of radioactive radon gas in living areas PLTS Independent enquirers Creative thinkers Reflective learners We will focus on Team workers Effective participators Self managers
Extension questions: 1: Explain the difference between being irradiated and becoming contaminated by a radioactive source ? 2: If areas with high atmospheric concentrations of radon gas would you expect to see more deaths from lung cancer ? 3: About 1 in 25,000 people die from lung cancer cause by radon gas. Work out for the UK (pop. 60,000,000) how many people due a year from radon gas ? 4: Up to 40,000 people a year die form lung cancer form cigarette smoking, why is this said to be an avoidable risk ? Know this: a: Know that radon gas is responsible for majority of background radiation that we are exposed to. b: Know that homes built in radon areas need to be designed to protect its residents. Friday 21 October 2011 Introduction: Radon is a natural radioactive gas, which enters buildings from the ground and can cause lung cancer. Radon is formed as part of the normal radioactive decay chain of uranium. Radon is often the single largest contributor to an individual's background radiation dose, and is the most variable from location to location. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as attics, and basements. It can also be found in some spring waters and hot springs. Epidemiological evidence shows a clear link between breathing high concentrations of radon and incidence of lung cancer. P3.3 Living with radon
P3.3 a Look at the photograph and information and answer all the questions: Radon is a natural radioactive gas. You cannot see, hear, feel or taste it. It comes from the minute amounts of uranium that occur naturally in all rocks and soils. Radon is present in all parts of the UK, although the gas disperses outdoors so levels are generally very low Look at the map opposite left a) which areas of England have the lowest amount of radon and b) the highest amount of radon gas ? Explain how radon cancer can affect your general health ? Where does radon gas come from ? Radon affected areas in England Key concepts
P3.3 b Look at the photograph and information and answer all the questions: The Environmental Protection Agency, EPA, recommends you install a system to reduce radon gas in your home if the level of gas is 4 picocuries of radon per litres or air or higher. In an typical area with room air as high as 4 picocuries of radon per litre of air, the chances of dying are about 2 in 1000 which is the same chance as dying in a travel accident. How does having a solid concrete floor help reduce radon levels inside the home ? How does having a pump drawing air form underneath the basement to outside in the air help reduce radon levels ? What type of radiation does radon gas give out ? radon concrete floor pump gas Protecting your home against radon Key concepts
P3.3 Plenary Lesson summary: safety radon half year Friday 21 October 2011 About 400,000 homes have been built in areas in the UK with high levels of Radon seeping from bedrock deep underneath a homes foundations. Although safety features can be built in there is still a higher risk of dying form lung cancer in this homes. How Science Works: Research into how radioactive materials can be sued to image the body and treat cancer of the body including thyroid cancer. Preparing for the next lesson: On average _______ makes up about _______ of the annual dose of radiation for a UK citizen. In the UK about 2500 people die from every ______ from inhalation of radon gas. House designers can design in _______ feature to reduce the risk of inhalation of radioactive radon gas. Decide whether the following statements are true or false : False True 3: Houses can be modified to increase a person’s safety ? False True 2: More people die year for lung cancer caused by smoking ? False True 1: All of the UK is affected by high concentrations of radon in the atmosphere ?
P3.4 Radiation and health Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand the different types of radiation </li></ul><ul><li>Understand the benefits and risk to using radioactive materials in humans </li></ul><ul><li>Understand that some disease are treated using radiation </li></ul>We will focus on. Friday 21 October 2011 First activity: What types of diseases may require imagining using nuclear medicine rather than conventional X-rays and explain why doctors should log and record when patients are imaged using nuclear medicine ? Literacy: Radiation, alpha, beta, gamma, radioactive decay, irradiation, dose, exposure, penetration, risk and diseases. Numeracy: In any one day over 1500 patients bodies are medically images using nuclear medicine. Although X rays can show broken bone, nuclear imagining can reveal disease of key organs like the lungs heart and liver. PLTS Independent enquirers Creative thinkers Reflective learners We will focus on Team workers Effective participators Self managers
Extension questions: 1: What type of precautions should a hospital radiographer take when working with radioactive materials ? 2: How does medical imaging help us understand better how the body works when compared to using X-rays ? 3: Explain why there is a small risk to the patient who takes a radioactive tracer prior to medical imagining ? 4: Explain the difference between irradiation and contamination ? 5: Why is Iodine 131 used to treat thyroid cancer ? Know this: a: Know the different types of radiation. b: Know the benefits and risk to using radioactive materials. Friday 21 October 2011 Introduction: Medical imaging is the technique and process used to create images of the human body for clinical purposes. Imaging can include radiology and nuclear medicine to identify disease or damaged organs. Some diseases are also treated by using radioactive materials. Thyroid cancer is first removed by surgery and then treated using radioactive iodine (I 131 ). Iodine is only used by the thyroid and when accumulated will destroy the remaining cancerous thyroid cells. During treatment, you are isolated to protect other people form the radioactive iodine. The patient may also lose hair and suffer other types of symptoms for associated with radiation sickness. P3.4 Radiation and health
P3.4 Look at the photograph and information and answer all the questions: Radioactive iodine (I 131 ), an isotope of iodine that emits beta radiation is used for medical purposes to treat cancers of the thyroid gland which produces the hormone thyroxin. When a small dose of I131 is swallowed, it is absorbed into the bloodstream in the gut and concentrated from the blood by the thyroid gland, where it begins destroying the gland's cells. Once given Iodine 131 , why is the a patient advise to sleep away form their partners and use a separate toilet ? Explain how using iodine 131 treats the thyroid cancer ? What precautions should doctors and nurses take when using radioactive medicine like Ioidne 131 ? Key concepts
P3.4 Look at the photograph and information and answer all the questions: Why are nuclear imagining techniques better for making a diagnosis when compared to conventional X-rays ? Explain why there is a small risk to the a patient when taking smaller quantities of a tracer like Technetium 99 ? Full body scan - this is the most common study in Nuclear Medicine, using a phosphate compound labelled with a short lived tracer called Technetium (Tc 99 ). An example of a body scan is shown below left The body scan will reveal cancers, broken bones and abnormalities of the key organs pictured below. When a radioactive tracer using Tc 99 is injected into the body, scanning is performed 2 or more hours afterwards. A whole body scan will typically take about an hour to perform. Key concepts
P3.4 Plenary Lesson summary: lungs risk benefit X-rays Friday 21 October 2011 Any patient undergoing treatment for thyroid cancer using Iodine 131 is advised to do the following ingestion of Iodine 131 : a) Sleep alone away from partners. Use separate toilets and showering facilities and avoid sharing food or drinks. All these precautions are designed to reduce the risk form nuclear medicine to those people who are not being treated . How Science Works: Research into the ALARA principals and how employers reduce the risk of exposure to radioactive materials on behalf of their employees Preparing for the next lesson: Patients using nuclear medicine can ________ from these techniques but there is also usually a small _____. Nuclear imaging can be much more detailed when compared to conventional techniques like ______ and show damage or disease of key organs like the heart, ______ and liver. Decide whether the following statements are true or false : False True 3: There is a low risk to patients who are imaged using nuclear imaging ? False True 2: Nuclear imagining is more detailed when compared to conventional X rays ? False True 1: Thyroid cancers can be treated using Chlorine 131 ?
P3.5 Radiation and exposure Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand how using the ALARA principles minimises the risk of radiation for humans </li></ul><ul><li>Understand the properties of the three types of radiation, alpha, beta and gamma </li></ul>We will focus on. Friday 21 October 2011 First activity: Explain why employees who work with radioactive waste should expect that their risk to radioactive material is minimised by their employers ? Literacy: Radiation, irradiation, dose, exposure, alpha, beta, gamma, exposure, penetration, shielding protection and monitoring. Numeracy: There are three types of radiation. An alpha particle which is positively charged, a beta particle which is negatively charged and gamma rays with zero charge. PLTS Independent enquirers Creative thinkers Reflective learners We will focus on Team workers Effective participators Self managers
Extension questions: 1: Why are workers protected by the principles of ALARA when working with radioactive materials ? 2: Why are pregnant females not allowed to work with radioactive materials ? 3: How does the following reduce the risk of irradiation or contamination when working with radioactive materials a) wearing protective gloves b) wearing an apron or other waterproof outer clothing c) working behind glass that contains lead metal ? Know this: a: Know what ALARA stands for and how using these principles protects employee. b: Know the different penetrating abilities of alpha, beta and gamma radiation. Friday 21 October 2011 Introduction: All employers and employees who work with radioactive material must use the principals laid out by ALARA. This stands for As Low As Reasonably Achievable. Workers are monitored when at work to ensure that their exposure to radiation remains low. The scientific unit of measurement for radiation dose, is the millisievert (mSv). Because different tissues and organs have varying sensitivity to radiation exposure, the actual radiation risk to different parts of the body from an x-ray procedure varies. The term effective dose is used when referring to the radiation risk averaged over the entire body. Knowing your annual dosage allows you to calculate of risk and comparison to more familiar sources of exposure that range from natural background radiation to radiographic medical procedures. P3.5 Radiation and exposure
P3.5 a Look at the photograph and information and answer all the questions: ALARP stands for "as low as reasonably practicable.“ The ALARP principle is that the risk to radiation shall be as low as reasonably practicable. The ALARP principle arises from the fact that infinite time, effort and money could be spent on the attempt of reducing a risk to zero, but in everyday situations for workers who are around radioactive materials zero risk or exposure is impossible. Why do we need to protect workers who are exposed to radioactive materials ? Why do workplace where workers work with radioactive materials have to monitor their workforce ? The badges that workers where have photographic film inside of them. How do this tell us how much radiation a worker has been exposed to ? Protecting your employees Key concepts
P3.5 b Look at the photograph and information and answer all the questions: Compare the outcomes of a person who receives a dose of more than 2000 rads and a person who receives a dose of less than 5 rads ? For a person exposed to a dose of between 300 to 500 rads what is the man cause of their death ? 50 to 150 rad: Slight blood changes including temporary drop in production of new blood cells will be noted and likely symptoms of nausea, fatigue and vomiting for one or two days More than 2,000 rad: Death is a certainty. At doses above 5,000 rad, the central nervous system (brain and muscles) can no longer control the body functions, including breathing and blood circulation.. Death occurs within days or hours. 1,000 to 2,000 rad: The probability of death is very high. The initial symptoms appear immediately. A few days later, things get very bad, very quickly since the gastrointestinal system is destroyed. Once the digestive system ceases to function, nothing can be done. 150 to 1,100 rad: Severe blood changes occur with symptoms appearing immediately. At 300-500 rad, up to one half of the people exposed will die within 30 days. Death is due to the destruction of the blood forming organs. Less than 5 rad: No immediate observable effects Understanding the health effects of exposure to radioactive materials allows us to calculate the risk of a population living with radioactive materials including radioactive waste. In particular it allows us to determine the risk ob behalf of workers who work on a daily basis in the nuclear industry particularly if there is an accident like 3 mile island and Chernobyl. Key concepts
P3.5 c Look at the photograph and information and answer all the questions: Explain why it is completely safe to hold an alpha emitter ? Which type of radiation would you use to check the quality of welding between train tracks and explain why ? When unstable atoms decay they give out radiation. There are three types of radiation, alpha, beta and gamma. Alpha radiation is a helium nucleus. Beta radiation is a stream of negatively charged electrons. Gamma rays like light travels in wave form. Gamma rays have between 1,000 and 1,000,000 times the energy of visible light and are the most penetrating able to go through lead and concrete. Beta particles are stopped by 3mm aluminium and alpha particles are stopped by thin paper. Types of radiation Key concepts
P3.5 Plenary Lesson summary: cancers risk low exposure Friday 21 October 2011 Badges containing undeveloped photographic film work by recoded expose to radioactive sources over a fixed time. When developed a company can record an employee’s total dose received whilst at work. If the results show high exposure, then the employee can be treated or monitored or signs of radiation sickness. How Science Works: Research into what make an radioactive elements unstable, how it transmutes or decays and the three types of radiation alpha beta and gamma. Preparing for the next lesson: Employees who work with radioactive material must be confident that their ______ is as reasonably ____ as achievable. This means that their _________ over their working lives remains low so they don’t have a greater chance of dying from ______ associated with radiation . Decide whether the following statements are true or false : False True 3: Employees use badges to record their exposure to UV sunlight when at work ? False True 2: ALARA is short for As Low As Reasonably Achievable ? False True 1: Radiograph working with radioactive materials have higher cancer rates ?
P3.6 Changes inside the atom Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand what makes an element or isotope of an element unstable ad radioactive </li></ul><ul><li>Understand how unstable isotopes decay </li></ul>We will focus on. Friday 21 October 2011 First activity: Think of three elements that are radioactive for example Urnaiun 235 ? Literacy: Radioactive decay, radioactivity, alpha, beta and gamma rays, unstable, isotopes, protons, neutrons and electrons. Numeracy: Half lives, the time taken for half the atoms of an unstable element to decay varies. The half life of Lead 214 is 26.8 minutes, where as the half life or Polonium 210 is a mere 0.00015 of a second The half life of Urnaium 235 is 4.5 x 10 9 years . PLTS Independent enquirers Creative thinkers Reflective learners We will focus on Team workers Effective participators Self managers
Extension questions: 1: What three sub atomic particles are all atoms made from ? 2: Name three radioactive elements, for example Uranium 235 ? 3: What two subatomic particles are found inside the atom’s nucleus and where are the electrons found ? 4: What combination of which type of sub atomic particles make an element unstable ? 5: Describe the main differences between alpha and beta particles ? Know this: a: Know what make radioactive elements unstable and decay. b: Know how radioactive elements decay through alpha beta and gamma radiation. Friday 21 October 2011 Introduction: Radioactivity is the disintegration of an atom of an unstable element. The stability of the nucleus depends on the relative numbers of protons and neutrons present. There are many elements have atoms or nuclei which are unstable and consequently split up to form smaller atoms. In the process of decay, the radioactive nuclei emits charged particles (alpha or beta) or electromagnetic rays (gamma rays) depending on the nature and it's instability. This results in a daughter nuclide being produced which may be radioactive or stable, but if it is radioactive it will in turn decay into a daughter nuclide, continuing to do so until it reaches the point of stability. P3.6 Changes inside the atom
P3.5 c Look at the photograph and information and answer all the questions: Which of the three types of radioactive particles are a) affected by a charged fields and b) which is the heaviest ? Which type of radiation travels at the same speed as visible light ? When unstable atoms decay they give out radiation. There are three types of radiation, alpha, beta and gamma. Alpha radiation is a helium nucleus. Beta radiation is a stream of negatively charged electrons. Gamma rays like light travels in wave form. Gamma rays have between 1,000 and 1,000,000 times the energy of visible light and are the most penetrating able to go through lead and concrete. Beta particles are stopped by 3mm aluminium and alpha particles are stopped by thin paper. alpha particles helium nucleus +ve charge Stopped by paper beta particles stream of electrons -Ve change stopped by 3 mm aluminium gamma rays wave form no charge penetrates concrete or lead Types of radiation Key concepts
P3.6 Look at the photograph and information and answer all the questions: Platinum is a chemical element with more than one isotope. Platinum 197 is an unstable atom and decays or transmutes by radioactive decay. Platinum 197 will decay turning itself into gold. Gold being less valuable than platinum does not this making this a money making scheme ! Platinum is used in Jewellery and in catalytic converters and dentistry When Platinum 197 decays what type of radiation is given out ? Explain why Platinum 197 is radioactive ? Could you make and sell jewellery from Platnium 197 ? Platnium 197 into gold gold Platinum 197 beta radiation Key concepts
P3.6 c Look at the photograph and information and answer all the questions: Unstable isotopes decay by emitting either alpha, beta or gamma radiation, forming new elements. The time taken for half the atoms to decay is called the half life of the substance. Half-lives of different isotopes vary, from fractions of a single second to many millions of years. Plutonium 240 has a relatively short half life of 6500 years. Uranium 235 has a relatively long half life of approximately 700 million years. If you started with 100 Lead 214 atoms with a half life of 26.8 minutes. How many atoms would have decayed after 13.4 minutes ? Look at the list of radioactive elements listed opposite left. Which has the shorted and longest half life ? Give one use for Uranium 238 and why is storing waste Urnaium 238 very difficult based on its half life ? Radioactive decay Uranium 238 Radon 222 Lead 214 Polonium 210 4.5. x 10 9 Year s 3.825 days 26.8 minutes 0.00015 seconds Key concepts
P3.6 Plenary Lesson summary: stable particle unstable transmute Friday 21 October 2011 When radioactive elements decay, they also release vast amounts of energy. Uranium 235 is used by nuclear power stations. Enriched Uranium 235 whilst decaying superheat water to produce stem which then turns a turbine generator which in turn generates electricity. Nuclear power although produces a lot of radioactive waste is carbon neutral How Science Works: Reach into nuclear power and how Urnaium 235 is used to generate electricity. Look also into nuclear weapons. Preparing for the next lesson: The emission of an alpha or beta ________ from the nucleus of an __________ element like Uranium 235 or Plutonium 210 produce a new element. The new element may also be unstable and continue to decay or ________ until a _______ final element is formed Decide whether the following statements are true or false : False True 3: Gamma rays travel at the same speed as visible light ? False True 2: Beta particles are a stream of negatively charge electrons ? False True 1: There are three types of radiation, alpha, beta and gamma ?