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Pennies Are Protons Teacher Guide

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LESSON STUDENT TEACHER WORKSHEET GUIDE Pennies are Protons Learn nuclear science at home A JINA/NSCL outreach service by Zach Constan Version 1.0 • April 2020 You are made of atoms. Atoms are tiny building blocks of matter that Introduction come in many different types (ele- The Atom ments) and make up all the objects you know: pencils, cars, the Earth, Teacher’s notes will appear in this the Sun. Atoms consist of a core margin. of protons and neutrons called the “nucleus” which is surrounded by a This was adapted from a series of documents related to the Marble Nuclei “cloud” of electrons. The electrons Figure 1. A schematic of the atom Project, downloadable from are MUCH farther away than in (Bohr model, not to scale). https://www.jinaweb.org/education- the picture at right! al-outreach/marble-nuclei-lessons The nucleus of the atom is : if an atom was the size of a football small These lessons were featured in AAPT’s field, the nucleus would be a golf ball sitting on the 50-yard line. Yet the The Physics Teacher: nucleus is critical to how our universe works, and so scientists in the http://dx.doi.org/10.1119/1.3293660 Joint Institute for Nuclear Astrophysics (JINA) study it every day. They need advanced research facilities such as the National Superconduct- The Marble Nuclei lessons/activities ing Cyclotron Laboratory (NSCL) at Michigan State University (and its are only one of the outreach programs upgrade, the Facility for Rare Isotope Beams, or FRIB). offered by JINA at https://www.jinaweb.org/educa- You can picture what a nucleus is like by building a model. Scientists tion-outreach use models to envision things they can’t look at easily, like how galaxies form over billions of years or how a low-pressure front will affect the This material is based upon work sup- weather tomorrow. We can never see the nucleus directly, so it helps to ported by the National Science foun- make a model and consider how it is (or is not) like a real nucleus! dation uner Grant No. PHY-1430152 (JINA Center for the Evolution of For your model of a nucleus, you’ll need a few small items to represent Elements) protons and neutrons, eight of each. For example: • Coins: pennies could be protons while nickels are neutrons • Two colors of LEGO bricks You may want to reinforce that the • Two colors of beads student will be using a model which • Two kinds of cereal doesn’t accurately represent the nucle- • Two colors of M&Ms – just don’t eat them us or its behavior. until after you’ve mastered nuclear science The examples in this document will all use coins. Remember: whatever items you choose Figure 2. to represent protons and neutrons, they really A penny-nickel nucleus ARE made of protons and neutrons! You’ll also need paper or plastic plate, a periodic table and the Chart of Nuclides (both attached at the end of this document). © 2012 Michigan State University Board of Trustees. MSU is an affirmative-action, equal-opportunity employer. 1 Part 1 The Periodic Table Naming Nuclei 1 2 H He Hydrogen Helium Students will learn about matter on the 3 4 5 6 7 8 9 10 Li Be B C N O F Ne subatomic scale Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar - examining the nucleus Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine Argon 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 - identify the nucleus according to its K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton element and isotope 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd ln Sn Sb Te I Xe Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon 55 56 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba Lu Hf Ta W Re Os lr Pt Au Hg TI Pb Bi Po At Rn Cesium Barium 57 - 70 Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon 87 88 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 Fr Ra Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og Francium Radium 89 - 102 Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson 57 58 59 60 61 62 63 64 65 66 67 68 69 70 *Lanthanide series La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium **Actinide series 89 90 91 92 93 94 95 96 97 98 99 100 101 102 Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium The Periodic Table features the Figure 3. The known elements in our universe. Periodic Table Each element has a unique “atomic of the Elements 4 number” - all atoms of that ele- (above) and the ment have that number of protons Table entry for the element be- in their nucleus. For example, the Be ryllium (Be). The Beryllium element beryllium has four protons. atomic number Having four protons is what makes appears at the top. it beryllium! Build a model beryllium nucleus by arranging four of your “proton” pieces together in a group. Almost all nuclei contain neutrons as well as protons, so your model should too! Examine the nucleus at right. It has 4 protons, which N P N makes it the element beryllium. It N P 9Be also has 5 neutrons, for a total of P N 9 particles. We call that nucleus N P beryllium-9. Figure 4. Schematic of a beryllium-9 Build a beryllium-9 nucleus by add- nucleus (left) and a corresponding ing five “neutron” pieces! “nucleus” of coins (right) You could imagine the beryllium nucleus having fewer neutrons; for instance, only 4, for a total of 8 particles. Change your nucleus into beryllium-8 (4 proton pieces and 4 neutron pieces), then a beryllium-10 to see the difference. Figure 5. Comparison of beryllium-8 (left) versus beryllium-10 (right) Compare the two varieties of beryllium you made (and in the figure); both are the same element with the same chemical properties - they could serve the same function in your body, for example. 2 © 2012 Michigan State University Board of Trustees. MSU is an affirmative-action, equal-opportunity employer. P The number of neutrons can go farther up or down, making manyN vari- N eties of beryllium, also known as “isotopes”. Just as the numberP of Npro-N P 10 tons determines what element your nucleus is, the number of neutronsN Be determines which isotope of that element. P N Figure 6. Several nuclei with a common number of protons (same element), but νe varying numbers of neutrons (different isotopes of that element). You can name any nucleus (like the example at Checkpoint: Find out if students can right) in a few steps: P N specify how to name an isotope. 1. Count the number of protons in it. This atom- N - ic number (also called “Z”) represents the N P 10 Answer: eProton number represents el- P P ement, and adding neutrons yields the protons that determine what element this B total number of particles to determine nucleus is. N N P the isotope. 2. Give it an element name or a “sym- bol” (short version on the Periodic Figure 7. Name this nucleus: Table). A nucleus with this many pro- what element/isotope? tons is the element boron, or symbol “B”. Find it in the Periodic Table and check the atomic number. 3. Count the number of neutrons in it. Neutrons determine what isotope the nucleus is. This number is often called “N”. 4. The number of neutrons plus protons determines what isotope of This is the step that is most often boron it is. This total is also called “mass number” and represented missed! The isotope is the SUM of by the letter “A”. Add the protons and neutrons to get the total number protons and neutrons. of particles in this nucleus: Z + N = A 5. Write the name of this nucleus using the element name/symbol and Answer: boron-10, B-10, 10B isotope/mass number as “Name-A” or “Symbol-A” or “ASymbol”. Try the opposite way: starting with the name of a nucleus, carbon-12 Answer: 6 pennies, 6 nickels (also known as C-12 or 12C), build it with your proton and neutron pieces. By adding or taking away neutron pieces, you can make many different Chart of the Nuclides isotopes of one element. You could imagine organizing all of these iso- topes on a graph, according to the number of neutrons on the horizontal x-axis and the number of protons on the vertical y-axis. Laying out isotopes this way is great for visualizing their organization.
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