Physical science Module 1 WK. 1 (2)
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Westmead International School**We aren't endorsed by this school
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SCI 1
Subject
Astronomy
Date
Dec 29, 2024
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14
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TITLE/TOPICS FORMATION OF HEAVIER ELEMENTS STANDARDS Content Standard: The learners demonstrate an understanding of the different types of waste materials Performance Standard: The learners demonstrate that you will create an output that discusses the origin of one of the man-made elements.Learning Objective: ●At the end of the lesson, I should be able to: 1.Discuss the stellar nucleosynthesis; 2.Give evidence for the formation of heavier elements during star formation and evolution; 3.Describe the formation of heavier elements during star formation and evolution; 4.Make a creative representation on the formation of heavier elements during star formation and evolution; and 5.Write the nuclear reactions involved in the formation of heavier elements. Most Essential Learning Competencies (MELC):●Give evidence and describe the formation of heavier elements during star formation and evolution. GENERAL INSTRUCTIONS To do well in this module, you need to remember and do the following: 1.Answer all the exercises and process questions completely. 2.Study the explanation well. 3.Supplement yourself with other learning materials when available and necessary. 4.Write down your thoughts to help to process information. 5.Keep in mind that your success in this module depends on how much effort you put into doing the activities in this module. Have fun!Going through this module can be a meaningful learning experience. All you need to do is make use of your time and resources efficiently. To do this, here are some tips for you: 1. Take the pretest before reading the rest of the module. 2. Take time in reading and understand the lesson. Follow instructions carefully. Do all activities diligently. This module is designed for independent or self-paced study. It is better to be slow but sure than to hurry and miss the concepts you are supposed to learn. 3. Use a clean sheet of paper for your answers in each activity/ assessment. Don’t forget to write your name. Label it properly. 4. Try to recall and connect the ideas about waves that you had in the lower years. Use the concept discussed in the lesson to explain the results of activities or performance tasks. You may answer in English or a combination of your vernacular and English. 5. Be honest. When doing the activities, record only what you have really
observed. Take the self-assessment after each activity, but do not turn to the Answer Key page unless you are done with the entire module. 6. Don’t hesitate to ask. If you need to clarify something, approach or contact your teacher or any knowledgeable person available to help you. You may also look into other references for further information. There is a list of references at the back part of this module. Pre-Assessment Multiple Choice. Choose the letter of the best answer. Write the chosen letter on the space provided before each number. ___ 1. The formation of the elements is known as _______________. a. Nucleotides b. Nuclear fission c. Synthogenesis d. Nucleosynthesis ___ 2. How many types of nucleosynthesis are there? a.1 b. 2 c. 3 d. 4 ___ 3. The first elements were formed in what is known as _____________. a. Big bang nucleosynthesis b. Supernova nucleosynthesis c. Stellar nucleosynthesis d. Genonucleosynthesis ___ 4. The two elements formed in Big Bang Nucleosynthesis where _________. a. Hydrogen and helium b. Hydrogen and lithium c. Hydrogen and oxygen d. Helium and lithium ___ 5. ______________ Nucleosynthesis happens in the center of the stars and is where the elements helium through iron (Fe) are formed. a. Big Bang b. Stellar c. Supernova d. Red Giant ___ 6. Stellar Nucleosynthesis stops at the element iron because there are __________ in their nuclei. a. Not enough protons b. Not enough protrons c. Not enough electrons d. Not enough neutrons ___ 7. All elements bigger than iron in the periodic table are formed in ________. a. Big bang nucleosynthesis b. Stellar nucleosynthesis c. Supernova nucleosynthesis d. Genonucleosynthesis ___ 8. Three helium nuclei fuse to form ___________. a. Carbon b. hydrogen c. lithium d. phosphorus ___ 9. The temperature in a supernova can reach ______________ and allows the heavier elements to form (along with abundant neutrons). a. 15 billion °C b. 100 billion °C c. 15 million °C d. 100 million °C ___10. How many light elements were created after Big Bang Nucleosynthesis? a. 1 b. 2 c. 3 d. 4
LESSON/CONTENT We are all made of Star Stuff (Formation of Heavier Elements) This module was designed and written with you in mind. It is here to help you master the nature of physical science. The scope of this module permits it to be used in many different situations, and lets you explore the vast concept of physical science. The lessons are arranged to follow the standard sequence of the course. The Formation of Heavier Elements during Star Formation and Evolution Elements heavier than beryllium are formed through stellar nucleosynthesis. Stellar nucleosynthesis is the process by which elements are formed within stars. The abundances of these elements change as the stars evolve.Evolution of Stars The star formation theory proposes that stars form due to the collapse of the dense regions of a molecular cloud. As the cloud collapses, the fragments contract to form a stellar core called protostar. Due to strong gravitational force, the protostar contracts and its temperature increases. When the core temperature reaches about 10 million K, nuclear reactions begin. The reactions release positrons and neutrinos which increase pressure and stop the contraction. When the contraction stops, the gravitational equilibrium is reached, and the protostar has become a main sequence star. In the core of a main sequence star, hydrogen is fused into helium via the proton-proton chain. When most of the hydrogen in the core is fused into helium, fusion stops, and the pressure in the core decreases. Gravity squeezes the star to a point that helium and hydrogen burning occur. Helium is converted to carbon in the core while hydrogen is converted to helium in the shell surrounding the core. The star has become a red giant. When the majority of the helium in the core has been converted to carbon, then the rate of fusion decreases. Gravity again squeezes the star. In a low-mass star (with mass less than twice the Sun’s mass), there is not enough mass for a carbon fusion to occur. The star’s fuel is depleted, and over time, the outer material of the star is blown off into space. The only thing that remains is the hot and inert carbon core. The star becomes a white dwarf. However, the fate of a massive star is different. A massive star has enough mass such that temperature and pressure increase to a point where carbon fusion can occur. The star goes through a series of stages where heavier elements are fused in the core and in the shells around the core. The element oxygen is formed from carbon fusion; neon from oxygen fusion; magnesium from neon fusion: silicon from magnesium fusion; and iron from silicon fusion. The star becomes a multiple-shell red giant.
The fusion of elements continues until iron is formed by silicon fusion. Elements lighter than iron can be fused because when two of these elements combine, they produce a nucleus with a mass lower than the sum of their masses. The missing mass is released as energy. Therefore, the fusion of elements lighter than iron releases energy. However, this does not happen to iron nuclei. Rather than releasing energy, the fusion of two iron nuclei requires an input of energy. Therefore, elements lighter than and including iron can be produced in a massive star, but no elements heavier than iron are produced. When the core can no longer produce energy to resist gravity, the star is doomed. Gravity squeezes the core until the star explodes and releases a large amount of energy. The star explosion is called a supernova. Pieces of Evidence The discovery of the interstellar medium of gas and dust during the early part of the 20th century provided a crucial piece of evidence to support the star formation theory. Other pieces of evidence come from the study of different stages of formation happening in different areas in space and piecing them together to form a clearer picture. Energy in the form of Infrared Radiation (IR)is detected from different stages of star formation. For instance, astronomers measure the IR released by a protostar and compare it to the IR from a nearby area with zero extinction. Extinctionin astronomy means the absorption and scattering of electromagnetic radiation by gases and dust particles between an emitting astronomical object and an observer. The IR measurements are then used to approximate the energy, temperature, and pressure in the protostar.The Nuclear Fusion Reactions in Stars Stellar nucleosynthesis is the process by which elements are formed in the cores and shells of the stars through nuclear fusion reactions. Nuclear fusion is a type of reaction that fuses lighter elements to form heavier ones. It requires very high temperatures and pressures. It is the reaction that fuels the stars since stars have very high temperatures and pressures in their cores. Hydrogen is the lightest element and the most abundant in space. Thus, the formation of heavier elements starts with hydrogen. Hydrogen burning is the stellar process that produces energy in the stars. There are two dominant hydrogen burning processes, the proton-proton chain and carbon-nitrogen-oxygen (CNO) cycle.
Proton-Proton Chain The proton-proton chainis a series of thermonuclear reactions in the stars. It is the main source of energy radiated by the sun and other stars. It happens due to the large kinetic energies of the protons. If the kinetic energies of the protons are high enough to overcome their electrostatic repulsion, then proton-proton chain proceeds. The sequence proceeds as follows: 1. The chain starts when two protons fuse. When the fused proton breaks, one proton is transmuted into a neutron. 2. The proton and neutron then pairs, forming an isotope of hydrogen called deuterium. 3. Another proton collides with a deuterium forming a helium-3 nucleus and a gamma ray. 4. Finally, two helium-3 nuclei collide, and a helium-4 is created with the release of two protons. Carbon-Nitrogen-Oxygen (CNO) Cycle For more massive and hotter stars, the carbon-nitrogen-oxygen cycle is the more favorable route in converting hydrogen to helium. The cycle proceeds as follows: 1. Carbon-12 captures a proton and gives off a gamma ray, producing an unstable nitrogen-13. 2. Nitrogen-13 undergoes beta decay to form carbon-13. 3. Carbon-13 captures a proton and releases a gamma ray to become nitrogen14. 4. Nitrogen-14 then captures another proton and releases a gamma ray to produce oxygen-15. 5. Oxygen-15 undergoes beta decay and becomes nitrogen-15. 6. Finally, nitrogen-15 captures a proton and gives off helium (alpha particle) ending the cycle and returning to carbon-12.
Unlike the proton-proton chain, the CNO cycle is a catalytic process. Carbon12 acts a catalyst for the cycle. It is used in the initial reaction and is regenerated in the final one. Nucleosynthesis is the process by which new nuclei are formed from preexisting or seed nuclei. Previously, you have learned about the types of nucleosynthesis. The big bang nucleosynthesis produced hydrogen and helium, whereas the stellar nucleosynthesis produced elements up to iron in the core of the stars. If the stellar nucleosynthesis produced only elements up to iron, then what type of nucleosynthesis produced the elements heavier than iron? The fusion reactions cannot produce nuclei higher than iron-56 because fusion reaction becomes unfavorable. This is because the nuclear binding energyper nucleon, the energy that holds the nucleus intact, decreases after iron-56. Therefore, different pathways are needed for the synthesis of heavier nuclei. Synthesis of heavier nuclei happens via neutron or proton capture processes. The fusion reactions cannot produce nuclei higher than iron-56 because fusion reaction becomes unfavorable. This is because the nuclear binding energy per nucleon, the energy that holds the nucleus intact, decreases after iron-56. Therefore, different pathways are needed for the synthesis of heavier nuclei. Synthesis of heavier nuclei happens via neutronor proton capture processes. In neutron capture, a neutron is added to a seed nucleus. The addition of neutron produces a heavier isotope of the element. For example, iron-56 captures three neutrons to produce iron-59. The generated isotope, when unstable, undergoes beta ( β −1 0 ) decay. This decay results in an increase in the number of protons of the nucleus by 1. Hence, a heavier nucleus is formed.
Beta decay results in the formation of a new element. For example, the unstable iron-59 undergoes beta decay to produce cobalt-59.Slow neutron captureor s-processhappens when there is a small number of neutrons. It is termed slow because the rate of neutron capture is slow compared to the rate of ( β −1 0 ) decay. Therefore, if a ( β −1 0 ) decay occurs, it almost always occurs before another neutron can be captured. Rapid neutron captureor r-process, on the other hand, happens when there is a large number of neutrons. It is termed rapid because the rate of neutron capture is fast that an unstable nucleus may still be combined with another neutron just before it undergoes ( β −1 0 ) decay. The r-process is associated with a supernova. The temperature after a supernova is tremendously high that the neutrons are moving very fast. Because of their speed, they can immediately combine with the already heavy isotopes. This kind of nucleosynthesis is also called supernova nucleosynthesis. Proton capture(p-process) is the addition of a proton in the nucleus. It happens after a supernova, when there is a tremendous amount of energy available. It is because the addition of a proton to the nucleus is not favorable because of Coulombic repulsion, which is the repulsive force between particles with the same charge. FIRM UP Activity 1. Crossword Puzzle Complete the crossword puzzle using the clues below the puzzle.
Guide Questions: Q1. What is Big Bang Theory? Q2. Give 3 evidences that explain the formation of the light elements in the Big Bang Theory. Q3. Name at least 4 light elements formed in the Big Bang Theory. Activity 2. Cosmic Connection: Jumbled UNIVERSE Identify the jumbled words being presented below. Write the CAPITAL LETTER on the space provided. Activity 3. Putting it All Together Read the selection and answer carefully the questions that follow.
Q4a. Identify the letter that corresponds to the correct order as shown in the illustration below. Write your answer on the space providedQ4b. Fill in the graphic organizer based on the given selection. Activity 3.1: Video Clip Watching and Analysis Watch the video clip on the formation of heavier elements during star formation and evolution ( https://www.youtube.com/watch?v=oLAEjxAD4Tc ) in order to answer the following guide questions. Guide Questions: Q5. How were elements heavier than beryllium formed? Q6. What are the pieces of evidence supporting the star formation theory?DEEPEN Activity 3.2: Model Me Up! Create a model to represent the reactions by which stars convert helium into heavier elements.
Q7. How did you come up with your creative representation regarding our topic? Q8. Write a brief description on the Creative Representation made.Performance Task Quite a few elements were first discovered as man-made elements since many of them did not emerge from the major nucleosynthesis reactions (or their minor processes). For this activity, you will create an output that discusses the origin of one of the man-made elements. Note: You may choose elements from Americium through Lawrencium as well as some of the recently discovered elements like Flerovium and Livermorium. In your output, you must: • discuss the element’s basic characteristics; and • give a brieftimeline leading up to the element’s discoveryYou may present your research in the form of poster, PowerPoint Presentation, essay, video, or infographic. Rubric for the Performance Task
INTEGRATION OF FAITH, VALUES, AND LEARNING And God said, g“Letthe waters under the heavens be gathered together into one place, and let the dry land appear.”And it was so.Genesis 1:9 https://biblia.com/bible/esv/genesis/1/9 ASSESSMENT Multiple Choice.Choose the letter of the best answer. Write the chosen letter on the space provided before each number. ___ 1. Which of the following describes stellar nucleosynthesis? a. It is the process by which elements are formed within stars. b. It is the formation of elements during a supernova explosion. c. It is the process by which elements are produced in gas clouds. d. It is the formation of light elements such as hydrogen and helium. ___ 2. Which of the following is a stellar core formed when the fragments of a collapsed molecular cloud contract? a. Protostar b. Supernova c. Red Giant d. Main Sequence Star ___ 3. Which of the following is a star that has used up its hydrogen supply in the core and switched into the thermonuclear fusion of hydrogen in the shell surrounding the core? a. Protostar b. Supernova c. Red Giant d. Main Sequence Star ___ 4. The formation of a star starts with the dense regions of molecular clouds. What force pulls matter together to form these regions? a. Magnetic Force b. Nuclear Force c. Electromagnetic Force d. Gravitational Force ___ 5. What happens when most of the hydrogen in the core is fused into helium in the stellar core? a. Hydrogen fusion continues, and the pressure in the core decreases. b. Hydrogen fusion continues, and the pressure in the core increases. c. Gravity squeezes the star until helium and hydrogen burning occur. d. Nuclear energy increases until carbon and helium burning occur. ___ 6. Which of the following elements are not formed during stellar evolution? a. Carbon b. Oxygen c. Gold d. Iron ___ 7. When does a massive star enter the stage of becoming a supernova? a. when the silicon fusion stops b. when the star has used up all its hydrogen fuel gold c. when the chromium fusion stops d. when the star has burned all its oxygen ___ 8. Which of the following processes is likely to generate the heaviest element? a. CNO Cycle
b. r –process c. triple alpha process d. Big Bang Nucleosynthesis ___ 9. Where can you find the heavy elements in the star? a. Red Giant b. Core c. Protostar d. Main Sequence Star ___ 10. What is the correct order for the stages of stellar evolution of a low–mass star? a. red giant –white dwarf –main sequence star –protostar b. main sequence star –white dwarf –protostar –red giant c. protostar –main sequence star –red giant –white dwarf d. white dwarf –red giant –protostar –main sequence starREFERENCES: 2020. ABS Free Pic. Accessed 26 May , 2020. http://absfreepic.com/free-photos/ download/light-bulb-lamp-. Advameg, Inc. 2020. Chemistry Explained. Accessed 26 May, 2020. http://www. chemistryexplained.com/Ar-Bo/Atomic-Nucleus.html. Asia, The Hive. 2018. Yahoo.com. 16 February . Accessed 29 May , 2020. https://ph. news.yahoo.com/sharon-cuneta-shares-details-past-. Bohr atomic model. (2015). In Encyclopædia Britannica Online. Retrieved October 27, 2015 from http://www.britannica.com/science/Bohratomic-model Chadwick discovers the neutron. (1998). Retrieved October 27, 2015 from http://www.pbs.org/wgbh/aso/databank/entries/dp32ne.html Chronology of Discoveries in Atomic Structure. (n.d.) Retrieved October 27, 2015 from http://www.chemteam.info/AtomicStructure/ HistAtomicStructure.pdf Henry Moseley. (2014, December 29). Retrieved October 27, 2015 from http://www.famousscientists.org/henry-moseley/ Rutherford atomic model. (2015). In Encyclopædia Britannica Online. Retrieved October 27, 2015 from http://www.britannica.com/science/ Rutherfordatomic-model