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Brief History of Radioactivity
Radioactivity is the spontaneous emission of particles or energy from unstable atomic nuclei to become more stable. It was discovered in 1896 by Henri Becquerel when studying uranium salts that emitted rays and could burn skin. Later, Marie and Pierre Curie isolated the radioactive elements radium and polonium, and defined their property of half-life. There are three main types of radioactive emissions - alpha, beta, and gamma rays - which were categorized by their ability to ionize atoms as either ionizing or non-ionizing radiation.
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Brief History of Radioactivity
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- 2. Radioactivity • Unstable nucleusspontaneously emits small particles and/or energy in order to attain a more stable nuclear state.
- 3. 1895 – WilhelmRoentgen • Nobel Prize in physics in 1901
- 4. 1896 – HenriBecquerel • Discovered Radioactivity • Phosphorescence o Uranium salts • Nobel Prize in 1903
- 5. 1898 – Marieand Pierre Curie • First Radioactive elements o Radium and Polonium • Polonium o Half-life Uraninite
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- 8. What is “radioactivity”? •Emissions o Not affected by temperature o Could change color of glass o Burn skin o Create heat • Rutherford and Soddy (1908) o TRANSMUTATION of one element to another • The atom is not an indestructible unit!
- 9. Types of Radiation •Non-ionizing (low energy) o Low frequency • Ionizing (high energy) o High frequency • Activity! o Label where you think non-ionizing and ionizing radiation are in the spectrum o categorize
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Editor's Notes
- #4 On Dec. delivered prelim paper on xraysThe Term x-ray, x for an unknownCaused a great stir, may have been ignored had it not been for the xrays of his hands which took 3-10 mins to acquire. He produced evidence!1st physics nobel prize
- #5 Believed that salts could emit penetrating x-ray like radiation when illuminated by bright sunlight.Phosphorescence-absorption of radiation, continues after radiation has stoppedInherited the salts from his father Uranium salts phosphoresce in prescence of lightUranium gave off radiation all by itselfImage of photographic plate fogged by exposure to radiation from uranium salt
- #6 Pierre suggested Marie do research from BecquerelCoined the name RadioactivitySubstance disappeared spontaneously reducing itself to one half in a certain timeUraninite (pitcheblende)Radium and calcium are bone seekersAplastric anemia – disease of the blood caused by defective function of the blood forming organs (bone marrow)Lab notebooks strongly contaminatedCookbooks are home were radioactive 50 years after her death (ask why they think it was still radioactive)
- #7 Radioactive tracer is added to a substance so it can be detected later. Can locate tumors, function of organs.
- #8 All radioactive elements decay with a specific half-lifeMake sure to mention that there are super high energy aka ionizing
- #9 It was the discovery and investigation of the phenomenon of radioactivity that led to our present understanding of the basic structure of the atom.
- #12 Nuclear fission is used to generate electricity as an alternative energy source.Fissions-spliting of nucleiFusion-combining 2 nuclei
- #13 The fission of an atom of uranium produces 10 million times the energy produced by the combustion of an atom of carbon from coal.