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Model of an atom
- 1 An atom consists of a positive nucleus and negative electrons. In a neutral atom, there are the same number of protons (positive charge) as electrons.
- 2 The nucleus may also contain neutrons. For example, the element Carbon-12 has 6 protons and 6 neutrons in the nucleus. To balance the positive charge, it has 6 electrons.
- 3 Some elements have isotopes. These are atoms with the same number of protons but different numbers of neutrons. An isotope of Carbon is C-14. This is an atom with 6 protons and 8 neutrons. It still has 6 electrons.
- 4 If an atom has one or more electrons removed, it is called an ion. It has positive charge. Helium-4 has two protons and 2 neutrons in the nucleus. Plus two electrons. If the two electrons are removed, we end up with an ion of Helium. It is just the nucleus of Helium and it is also called an alpha particle.
- 5 Some atoms are unstable. These atoms may have extra neutrons. To become more stable, these atoms release energy from the nucleus and this is called radiation.
What is radiation?
- 1 Energy from the nucleus is released in one of three ways : alpha, beta or gamma radiation.
- 2 Alpha radiation is the emission of an alpha particle (a helium nucleus) from the nucleus of an atom. In the process, the nucleus loses 2 protons and so the smaller nucleus is now a different element. Alpha particles carry positive charge.
- 3 Beta radiation is when the nucleus emits a fast moving electron (beta particle). It is not one of the electrons from the atom. Beta particles carry negative charge.
- 4 Gamma radiation. Unlike alpha and beta radiation, gamma is an electromagnetic wave. It travels at the speed of light and is part of the electromagnetic spectrum. Gamma radiation carries no charge.
- 5 When a substance emits radiation, it is said to be radioactive. It is impossible to tell when a nucleus will emit radiation because it is a totally random process.
Testing for radiation
- 1 Test for the presence of radiation using a Geiger Muller (GM) tube. This doesn’t reveal which type of radiation is being detected. Measure the background count and then do these tests.
- 2 Let’s assume that the GM tube is detecting a count rate that is higher than the background from a radioactive sample. Alpha is stopped by 5cm of air or paper. So placing paper between the GM tube and sample will reduce the count rate if alpha is present. If there is no change, then beta or gamma is present. Test for beta using aluminium sheet. If no change then gamma is present.
When this happens, the nucleus splits into two smaller parts that are nearly the same size. A smaller nucleus is released and at the same time so is a large amount of kinetic energy. The neutrons that are released are then able to hit more Uranium-235 nuclei which cause fission to occur regularly. This is known as a chain reaction. Control rods that contain boron absorb the neutrons and they are able to control the rate of reaction. Energy from the fuel rods s then transferred as heat to a coolant, this is usually water but can also be carbon dioxide.
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Marie Curie. The research done by the Curies was highly significant in the development of x-rays. During World War One, Marie Curie helped equip ambulances with x-ray equipment.
They married in 1895. The pair combined their knowledge and experience by working together investigating radioactivity in the laboratory, continuing on the work of German physicist Roentgen and French physicist Becquerel. Marie carried out chemical separations whilst Pierre neglected his study of crystals to create new laboratory equipment such as the ionisation chamber and took measurements. In July 1898, Marie and Pierre announced their discovery of a new chemical element, polonium (Po). Before the year had finished, the pair announced the discovery of another addition to the periodic table, radium (Ra).
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Smoke Alarms Assignment In this CDA I will be explaining how smoke alarms work, there are two types of smoke alarms, Ionisation smoke detectors and Photoelectric smoke detectors
The radioactive material ionizes the air in the chamber, which results in current flow between plates. Any smoke that comes into the chamber will interrupt the ion flow and cause a reduction in current flow that sets off the alarm. The differences between photoelectric and ionization smoke detectors are they both detect smoke differently, like for example the photoelectric smoke detectors uses an optical beam to search for smoke so when the smoke particles cloud the beam, a photoelectric cell senses the decrease in light intensity and triggers the alarm, as the ionisation smoke detector detects smoke when the it
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- a signal that varies continually What is gamma radiation? - electromagnetic wave/radiation Why are step-up transformers used? - increase voltage, increase efficiency, reduce current, reduce energy loss Environmental problem that burning fossil fuels produces? - produces pollutant gases, solid waste/ash/smoke Why are telescopes that detect different types of EM waves used to observe the Universe? - sources emit all different types of EM radiation/waves What is red-shift? - wavelength of light increases Describe the big bang theory? - explosion causes universe ro expand. Explain how heat is transferred by the process of convection from the gas flame at the bottom of the oven to the potatoes at the top of the oven?
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Also, lungs can be more easily damaged by gamma rays, therefore different treatments would be advised. Sterilising Gamma rays are used in hospitals to sterilise equipment. Normally equipment is sterilized using heat, but heat would damage some objects like syringes. Gamma rays are used to kill bacteria, mould and any possible living insects in the food. It also preserves the food so that it can remain on the shop's shelf for longer. However, it can have it's affects and can change the taste of the food. Dating Animals and plants have a known proportion of Carbon-14 (a radioisotope of Carbon)
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I will do research to find the best answer. Nuclear energy: Nuclear energy requires less fuel to work than fossil fuels but it has more harmful by-products. To make nuclear energy, one of these two substances are needed. Either uranium or plutonium. Uranium is naturally occurring, plutonium is not. Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts and free neutrons as well. The diagram shows uranium being split. It is a chain reaction that is controlled. Nuclear fission produces energy for nuclear power.
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The aim of this study is to find out how harmful sunbeds are for peoples health and if they should be used less or even banned.
Ions produced by the radiation can lead to chemical changes that can damage body tissue. When radiation takes place alpha and beta particles ionize the substances that they pass through. This is because their energy is so high they can cause electrons to be 'knocked out'. Picture of a sun bed 2 Reasons FOR using Sunbeds Reasons AGAINST the use of Sunbeds Promotes well-being and confidence Could cause skin cancer/tumours Produces melanin Costly Fashionable/trendy Sunburn/dehydration Pre-holiday tan Does not look natural - orangey Produces Vitamin D Could cause eye problems Don't have to wait for the summer Those with family history of skin problems Gives a nice brown healthy look People on medication People with
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I have discovered that by using dice it can actually model the process of radioactivity decay and that there are actually relations between the use of dice and actual decay of a substance. This is because the number of dice I "take out" from the first few shakes takes out more than half of the dice in the box.
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This is when you kill a human being with their consent however they have a nice and peaceful death. Several people ask for voluntary euthanasia for several reasons. Some may ask for it as they've found out they've got cancer they may not like this. Others may ask for voluntary euthanasia as the pain or symptoms of cancer may hurt them so much, whether that is physically or emotionally. This is because when you receive cancer, a lot of patients assume that they will die. Only recently, mobile phones have attracted several people, as there are several brands and there are more features to them in comparison to them ten years ago, they've attracted more people.
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Skin cancer is a feared illness and is a result of abnormal developing skin cells. And it is already mentioned that the perpetrator for the alarming illness is UV light (UVA). Cancer research UK says 'Malignant melanoma incidence rates in Britain have more than quadrupled since the 1970s'. Malignant melanoma is a very serious skin cancer which usually starts in the skin. It is due to "uncontrolled growth of pigment cells, called melanocytes."(Source 8) (Source 6) (Source 2) The risk of being diagnosed with malignant melanoma increases with age. The incident rates are highest in the over 55s, this is because these people are at an old age so their bodies are weaker hence they are more vulnerable to cancer.
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Radiation: are mobile phones unsafe? Mobiles use electromagnetic radiation in order to send and receive information. Electromagnetic radiation comes from the electromagnetic spectrum.
It can cause chemical reactions in the body, which can lead to cell changes and can then develop into cancerous cells/cancer. Electromagnetic waves are described by any one of the following 3 physical properties: frequency, wavelength and photon energy. Frequency is the number of occurrences of a repeating event per unit time. Wavelength is the distance between repeating units of a given frequency. Photon Energy is a packet of electromagnetic energy. The type of electromagnetic radiation mobile phones use is Microwaves.
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Most atoms do not have a full outer shell and try to react with another through either ionic bonding or covalent bonding. * Protons weigh relative in size to neutrons - 1 mass; however electrons are a lot smaller weighing relatively 0.0005 of mass. Discovery/Background knowledge: * Ernest Rutherford was fascinated by radioactivity and investigated it for twenty years, beginning at Havelock school, then Nelson College and won a scholarship to study at Canterbury College. * He named the easily absorbed rays 'alpha' and the penetrating rays 'beta'.
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The drop in current between the plates triggers the alarm. People worries about smoke alarms? House fires may smoulder in a couch for hours before bursting into flame, and there may be as little as three minutes to safety evacuate once there is an open flame. A real concern should be whether smoke detectors are located in the correct places to give an early warning. A detector should be placed in the hall outside bedrooms and the doors kept shut.
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And find a solution to the use of mobile phones. So the major question is that 'Are mobile really harmful to our health?' The answer is for you to discover as you keep on reading these case study. Arguments of those who believe that mobile phones are a risk to our health Harmful Effects of Radiation http://www.healthjockey.com/images/mobile-salivary-cancer.jpg Radiation is defined as energy that comes from a source and travels through space and may be able to penetrate various materials. So they are many effects this may cause.
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Then I will be able to do a simple evaluation, answering the question that my case study is set on. Then at the end I will list the sources where I have collected my information and pictures from in a Bibliography. Also, throughout the project, images that I include, like the one below will have a source beneath or to a side of them in a green font so that in the Bibliography I do not have to refer back to images.
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Simply put, the Manhattan Project was committed to expediting research that would produce a viable atomic bomb. The most complicated issue to be addressed in making of an atomic bomb was the production of ample amounts of "enriched" uranium to sustain a chain reaction. At the time, uranium-235 was very hard to extract. In fact, the ratio of conversion from uranium ore to uranium metal is 500:1. Compounding this, the one part of uranium that is finally refined from the ore is over 99% uranium-238, which is practically useless for an atomic bomb.
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Man-made lamps can also emit UV radiation, and are often used for experimental purposes. Light enables us to see, and heat keeps us from being cold. However, ultraviolet rays often carry the unfortunate circumstance of containing too much energy. For example, infrared rays create heat in much the same way as rubbing your hands together does. The energy contained in the infrared rays causes the molecules of the substance it hits to vibrate back and forth. However, the energy contained in ultraviolet rays is higher, so instead of just causing the molecules to shake, it actually can knock electrons away from the atoms, or causes molecules to split.
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Mobile Phones The mobile phone (commonly referred to simply as a mobile- or in Northern America a cell phone) is a short range (without the use of mobile phone masts which make it a long range device) portable electronic device used for mobile voice or data communication over a network of specialized base stations known as cell sites. The first commercial mobile phone service was launched in Japan by NTT in 1979, and by November 2007, the total number of mobile phone subscriptions in the world had reached 3.3 billion, or half of the human population (although some users have
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Once you have made your choice, the calculator will work out the possible impact in terms of carbon emissions, whether you managed to keep the lights on and how it will affect people's annual bills. The total demand for electricity in the UK is 358 billion kilowatt hours. The main sources of supply are: * Fossil fuels: 253 bn kWh * Nuclear: 80 bn kWh * Renewable: 15 bn kWh * Imports: 10 bn kWh In 2020, the UK's demand is projected to have grown to 381 billion kilowatt hours.
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Source 2 Wood, charcoal, marine and fresh water shells, bone & antler. Anything organic or once living. Grains, seeds, nutshells, grasses, twigs, cloth, paper, hide, burnt bones, organic material mixed with soil charcoal & wood charred bones Source 3 Radioactivity: Spontaneous changes in a nucleus accompanied by the emission of energy from the nucleus as a radiation. Radioactive Half-Life: A period of time in which half the nuclei of a species of radioactive substance would decay. We imagine that we have a radioactive substance. When the nuclei of the substance decay, they emit radiation (alpha, beta, or gamma rays)
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Radio: This is the same type of radio wave that is emitted by radio stations, but there not the only things that do, stars and gases in space also emit radio waves. The everyday uses of these are; AM and FM radios, Aircraft and shipping bands and shortwave radio. Radio waves penetrate the Y part of our atmosphere. The wavelength for radio is 10^3, and the frequency is 10^4. Microwaves: These are the same types used your microwave oven you use at home.
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Beakers made from different materials and colours. 3.) Conduction of Heat. Conduction of heat is the process where vibrating particles pass on their extra kinetic energy to neighbouring particles. 4.) Radiation. 5.) Evaporation. When a liquid below its boiling point changes into a gas, this is called evaporation. It happens because some particles in the liquid move faster than others. The faster ones near the surface have enough energy to escape to form a gas. 6.) Infrared. Energy to heat us up travels from the Sun at the speed of light, jut like the light rays.
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Zabaluyeva. It's hard to believe as the rays that the sun gives off are strong. Skin cancer is the most common cancer in Britain. Chloe Rhodes assesses the risks and benefits of sunshine This spring has been one of the sunniest on record, and as we head towards "flaming June", we can look forward to even warmer weather and clearer skies. But conflicting information about the effects of sun exposure on our health may leave us all longing for cloud cover. Sunbathing can have health benefits if done with care Warnings about the dangers of the sun are starker than ever, and skin cancer is now the most commonly diagnosed cancer in Britain.
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The steam drives turbines which drive generators producing the energy. (Updated: Nov 20, 2008, http://www.darvill.clara.net/altenerg/nuclear.htm). Diagram: What happens to a Uranium atom in Nuclear Fission? (Last updated: 5, Feb, 2009 Title: Nuclear Chemistry www.zamandayolculuk.com/cetinbal/nuclearchemistry.htm) What is Radiation? During the splitting of the atom Uranium (U235), or any other fissile nuclide [i.e. Plutonium], radiation is produced. Any material that produces radiation is radioactive. There are four types of radiation associated with nuclear fission, called ? (Alpha), ? (Beta), ? (Gamma) and Neutron radiation; this last type is emitted during the nuclear fission process. Neutrons are also very penetrative, but less so than gamma-radiation, and have an effect on human tissue approximately midway between beta and gamma-radiation.
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These types of radiation are referred to as 'ionizing radiation.' Reference: (http://www.epa.gov/radiation/understand/index.html#whatis) Radiation what it is? Alpha ? helium nucleus Beta � high-speed electron Gamma ? electromagnetic radiation Reference: (TWENTY FIRSTCENTUREY SCIENECE GCSE Science Higher) What is Uranium? Uranium is a weak radioactive metal that occurs throughout the earth's crust, being present in most rocks and soils along with many rivers and in seawater. Only slightly more radioactive than granite used in buildings, uranium is about 500 times more abundant than gold and about as common as tin. Natural uranium is primarily made up of two isotopes, uranium 235 and uranium 238.
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