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Half Life Decay Presentation (Chemistry for engineers)

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EmanuelLoto

This experiment involves measuring radioactivity using a Geiger counter. Students will detect background radiation and measure radiation levels from different radioactive samples. They will also explore how shielding materials can block radiation. To model radioactive decay and half-life, students will flip pennies and record the number remaining after each "decay" to graph decay over time. The objectives are to understand radioactive terminology, how Geiger counters work, sources of background radiation, half-life of radioactive isotopes, and analyzing experimental results compared to theoretical predictions.

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Half-life Decay (Nuclear Chemistry)
Objectives In this experiment, you will: Use the terminology of radioactivity and describe instruments that detects it Detect and measure radioactivity with a Geiger counter  Measure the local intensity of background radiation Determine the difference in penetrating power between different radioactive particles Simulate the process of half life using tossed pennies  Graph your results and gain an understanding of probability and error analysis
Intended Learning Outcomes (ILOs): a. Know how a Geiger Counter works. b. Know the sources of background radiation. c. Know the half-life in terms of radioactive isotopes. d. Know the effects of samples in experimental plot compared to theoretical.
Discussion: Radiation is all around us. There are two main types of radiation: ionizing and non-ionizing. We will focus on radioactivity or ionizing radiation (though non-ionizing radiation, such as ultraviolet, can also be harmful.) Radioactivity results from unstable nuclei decaying to more stable isotopes. The Sun produces cosmic rays, there are radioactive isotopes in the walls and air around us, and even people are radioactive. This natural radioactivity is called background radiation, and life on Earth has adapted to it. The variety of life probably comes from the mutations caused by radioactivity.
Nuclear reactions are different from chemical reactions primarily in the fact that the chemical identity of atoms can change. Nuclear reactions involve the spontaneous emission of nuclear particles or high energy, in the form of alpha, beta, or gamma radiation. These emissions can be detected by means of a Geiger counter. Individual atoms may decay at any time, but with a large enough sample, it can be stated that in a certain period of time, half of the sample will decay. This is called the half life, and is characteristic of each radioisotope. We will model half life decay to observe how this happens and learn about sample size and experimental error bars.
Materials:  Geiger Counter (radiation monitor) or Lab Quest Pro  Radioactive samples  Tongs (forceps)  Gloves  100 Pennies  Tub  Pen  Paper (Report Sheet
Procedure: Part A: MEASURING RADIOACTIVITY a. Use of the Geiger counter (radiation monitor) and Radioactive Samples 1. Setup and the use Geiger counter or Lab Quest Pro. 2. Use the instructions sheet which comes with the Geiger Counter. 3. Record the isotope for each source in the data table. 4. Using tongs remove one sample at a time from the sample case and place it about a yard from the other sources to cut down on interference. 5. Record cpm with the radiation monitor 1 cm away from the source, and again when it is 10 cm away from the source. (Make sure the window of the radiation monitor is facing the sample!)
b. Background Radiation 1. Move the radiation monitor away from the sample case, perhaps to the window or take it out to the window in the hallway. 2. Record the cpm. 3. Repeat three more times and average the data. 4. The actual radiation of a sample is measured by using the observed radiation for the sample minus the background radiation. Does this make sense? c. OPTIONAL: Shielding (design your own experiment!) The greater the penetrating power of the radiation, the more likely the radiation is to go through a material. Which materials are better shields (less penetration)? 1. Select ONE of the radiation sources to use (alpha, beta, or gamma). 2. Select least three different types of materials provided by your instructor (or ones you have, such as clothing or paper) to devise your own experiment to answer this question. 3. Record your method and data on the report sheet.
Part B: DEMONSTRATION OF HALF LIFE a. Pennies in the Tub 1. Obtain 100 pennies from your instructor and a tub provided in the classroom. 2. Arrange the pennies in a single layer on the bottom of the tub. 3. Carefully lift the tub and give it one shake straight up and down so that some of the pennies jump, but none are lost out of the tub. (Practice a few times before you start counting.)
b. Tub shake 1. Place the pennies all facing heads up in the bottom of the tub. 2. Give the tub one shake. 3. Remove all the pennies that are not heads up. This is one “flip”. 4. Record the number of heads left in the tub on the report sheet for this flip. 5. Make sure this number decreases with each flip. 6. Shake again and remove the tails for one more flip. 7. Record the data for each successive flip going down the column. 8. A total of 10 flips will be done for that sample. 9. Repeat the whole process for a total of three samples of 100 pennies each. c. Graph the data 1. Calculate the average value of heads up coins at each flip for all of your samples combined. 2. The average number of heads versus flip # (use graphing area provided on report sheet or use a spread sheet in the lab computers).
Hans Leo G. Diola Christian Franthel D. Escarro Emanuel G. Loto Jun Brian R. Dela Peña Argie Valendez Romelyn Jubay

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Half Life Decay Presentation (Chemistry for engineers)

  • 2. Objectives In this experiment, you will: Use the terminology of radioactivity and describe instruments that detects it Detect and measure radioactivity with a Geiger counter  Measure the local intensity of background radiation Determine the difference in penetrating power between different radioactive particles Simulate the process of half life using tossed pennies  Graph your results and gain an understanding of probability and error analysis
  • 3. Intended Learning Outcomes (ILOs): a. Know how a Geiger Counter works. b. Know the sources of background radiation. c. Know the half-life in terms of radioactive isotopes. d. Know the effects of samples in experimental plot compared to theoretical.
  • 4. Discussion: Radiation is all around us. There are two main types of radiation: ionizing and non-ionizing. We will focus on radioactivity or ionizing radiation (though non-ionizing radiation, such as ultraviolet, can also be harmful.) Radioactivity results from unstable nuclei decaying to more stable isotopes. The Sun produces cosmic rays, there are radioactive isotopes in the walls and air around us, and even people are radioactive. This natural radioactivity is called background radiation, and life on Earth has adapted to it. The variety of life probably comes from the mutations caused by radioactivity.
  • 5. Nuclear reactions are different from chemical reactions primarily in the fact that the chemical identity of atoms can change. Nuclear reactions involve the spontaneous emission of nuclear particles or high energy, in the form of alpha, beta, or gamma radiation. These emissions can be detected by means of a Geiger counter. Individual atoms may decay at any time, but with a large enough sample, it can be stated that in a certain period of time, half of the sample will decay. This is called the half life, and is characteristic of each radioisotope. We will model half life decay to observe how this happens and learn about sample size and experimental error bars.
  • 6. Materials:  Geiger Counter (radiation monitor) or Lab Quest Pro  Radioactive samples  Tongs (forceps)  Gloves  100 Pennies  Tub  Pen  Paper (Report Sheet
  • 7. Procedure: Part A: MEASURING RADIOACTIVITY a. Use of the Geiger counter (radiation monitor) and Radioactive Samples 1. Setup and the use Geiger counter or Lab Quest Pro. 2. Use the instructions sheet which comes with the Geiger Counter. 3. Record the isotope for each source in the data table. 4. Using tongs remove one sample at a time from the sample case and place it about a yard from the other sources to cut down on interference. 5. Record cpm with the radiation monitor 1 cm away from the source, and again when it is 10 cm away from the source. (Make sure the window of the radiation monitor is facing the sample!)
  • 8. b. Background Radiation 1. Move the radiation monitor away from the sample case, perhaps to the window or take it out to the window in the hallway. 2. Record the cpm. 3. Repeat three more times and average the data. 4. The actual radiation of a sample is measured by using the observed radiation for the sample minus the background radiation. Does this make sense? c. OPTIONAL: Shielding (design your own experiment!) The greater the penetrating power of the radiation, the more likely the radiation is to go through a material. Which materials are better shields (less penetration)? 1. Select ONE of the radiation sources to use (alpha, beta, or gamma). 2. Select least three different types of materials provided by your instructor (or ones you have, such as clothing or paper) to devise your own experiment to answer this question. 3. Record your method and data on the report sheet.
  • 9. Part B: DEMONSTRATION OF HALF LIFE a. Pennies in the Tub 1. Obtain 100 pennies from your instructor and a tub provided in the classroom. 2. Arrange the pennies in a single layer on the bottom of the tub. 3. Carefully lift the tub and give it one shake straight up and down so that some of the pennies jump, but none are lost out of the tub. (Practice a few times before you start counting.)
  • 10. b. Tub shake 1. Place the pennies all facing heads up in the bottom of the tub. 2. Give the tub one shake. 3. Remove all the pennies that are not heads up. This is one “flip”. 4. Record the number of heads left in the tub on the report sheet for this flip. 5. Make sure this number decreases with each flip. 6. Shake again and remove the tails for one more flip. 7. Record the data for each successive flip going down the column. 8. A total of 10 flips will be done for that sample. 9. Repeat the whole process for a total of three samples of 100 pennies each. c. Graph the data 1. Calculate the average value of heads up coins at each flip for all of your samples combined. 2. The average number of heads versus flip # (use graphing area provided on report sheet or use a spread sheet in the lab computers).
  • 11. Hans Leo G. Diola Christian Franthel D. Escarro Emanuel G. Loto Jun Brian R. Dela Peña Argie Valendez Romelyn Jubay