UC Irvine FOCUS! 5 E Lesson Plan Title: Marble Isotope Lab Grade Level and Course: 8 th Grade Physical Science and 9-12 High School Chemistry

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1 UC Irvine FOCUS! 5 E Lesson Plan Title: Marble Isotope Lab Grade Level and Course: 8 th Grade Physical Science and 9-12 High School Chemistry Materials: Red, blue and yellow marbles (25 each) Instructional Resources Used: (concept maps, websites, think-pair-share, video clips, random selection of students etc.) Think-pair-share - Students will watch videos, record all thoughts and perceptions, share with another student and then share out to class. Teacher will record all thoughts on the board. Venn diagram-students will create venn diagrams for two isotopes C-14 and C-12, neutral atoms. California State Standards: (written out) 8th Grade Physical Science 7. The organization of the periodic table is based on the properties of the elements and reflects the structure of atoms. As a basis for understanding this concept: b. Students know each element has a specific number of protons in the nucleus (the atomic number) and each isotope of the element has a different but specific number of neutrons in the nucleus. Investigation and Experimentation 9. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will: e. Construct appropriate graphs from data and develop quantitative statements about the relationships between variables High School Chemistry 11. Nuclear processes are those in which an atomic nucleus changes, including radioactive decay of naturally occurring and human-made isotopes, nuclear fission, and nuclear fusion. As a basis for understanding this concept: c. Students know some naturally occurring isotopes of elements are radioactive, as are isotopes formed in nuclear reactions. f. * Students know how to calculate the amount of a radioactive substance remaining after an integral number of half-lives have passed. Lesson Objectives: a. Students will successfully follow directions and complete the lab. b. Students will be able to differentiate between isotopes of the same element. c. Students will use correct notation to express isotopes. Differentiation Strategies to meet the needs of diverse learners: English Learners: Students will be divided in appropriate level learning groups, higher level EL students with lower level EL students. Prior to the lab, they will define the term isotope and complete the short attached worksheet in their

2 groups. Here are three isotopes of an element: 6 12 C 6 13 C 6 14 C a. The element is: b. The number 6 refers to the c. The numbers 12, 13, and 14 refer to the d. How many protons and neutrons are in the first isotope? e. How many protons and neutrons are in the second isotope? f. How many protons and neutrons are in the third isotope? Special Education: Using the above example, the teacher will have the students draw the nuclei of the isotopes and have the students verbalize the differences they see. GATE: Students will research the isotopes in the lab and report on the halflife of each. ENGAGE Describe how the teacher will capture the students interest. o Students will watch the short video clip o Students write down what they see. They will then pair with a group member to compare thoughts and finally will share out to the class their understanding of the clip. Use of venn diagrams could help in their descriptions. What kind of questions should the students ask themselves after the engagement? a. If all of the atoms are hydrogen, what makes them different? b. How are all three atoms the same? EXPLORE Describe the hands-on laboratory activity that the students will be doing. Students will be given bags with different numbers of red marbles representing protons, blue marbles representing neutrons and yellow marbles representing electrons. Students will build the nucleus for each of the atoms and then determine the element (based on number of protons ) and the atomic mass of the atom (protons + neutrons). Students will record their information in the data table. EXPLAIN List the big idea conceptual questions that the teacher will ask to focus the student exploration. a. If there are two atoms of the same element but they have different masses, what is the reason for the different masses? b. Can two different elements have the same atomic mass? What is the big idea concept that students should have internalized from doing the exploration? An element is defined by its atomic number, i.e., the number of protons in the nucleus, whereas its mass is the sum of the protons and neutrons in the nucleus. Atoms of the same element can have different masses based on the number of neutrons in the nucleus. List the higher order questions that the teacher will ask to solicit student explanations for their laboratory outcomes, and justify their explanations. a. Can different elements have the same mass? Why or why not?

3 EXTEND b. Does the number of electrons affect the mass of the isotopes? Why of why not? Explain how students will develop a more sophisticated understanding of the concept. Students will research two different isotopes of the same element, one stable and one non-stable. Students will design and build a poster explaining the two isotopes, how they are the same and how they are different. How is this knowledge applied in our daily lives? On the poster, students will draw or cut out pictures of the current uses and applications of the two isotopes. For the GATE student, they will explain half-life and how it is determined. EVALUATE How will the student demonstrate their new understanding and/or skill? Students will accurately fill-in the data table and answer the lab questions. Additionally, students will be able to identify examples of isotopes of the same element from a collection of isotopes on the end of unit test and benchmark exams. What is the learning product for the lesson? a. Successful completion of the lab. b. Correctly answering the lab questions. c. Accurate completion of the presentation board. Background Knowledge for the Teacher: Isotopes are basically the same element with a different number of neutrons. The nucleus of every atom is made up of neutrons and protons. While neutrons don t have a charge they do important work such as helping to bind the positive charged protons together via the strong force. Isotopes can have different numbers of protons but the basic elemental structure remains the same. For example deuterium will have one more neutron than normal hydrogen but it will still be considered hydrogen. The only thing that will change is the atomic weight. What is the importance of isotopes? Isotopes have a special set of properties called nuclear properties. For example certain isotopes are more prone to radioactive decay making them ideal materials to use in nuclear reactions. Source: Student pages are attached.

4 Marble Isotopes Background Info: Every atom of the same element has the same number of protons. Different atoms of the same element can have different numbers of neutrons. Because the protons and neutrons make up the mass of the atom, different atoms of the same element can have different masses! These are called isotopes. For example: Lithium (Li) has two isotopes. Both isotopes have 3 protons (atomic number 3), but one has 3 neutrons and the other has 4 neutrons! Example A: The Li isotope with 3 neutrons has a mass number of 6 (3p + 3n) Symbol is 6 3 Li Name is Lithium-6 Example B: The Li isotope with 4 neutrons has a mass number of 7 (3p + 4n) Symbol is 7 3 Li Name is Lithium-7 Purpose: In today s activity you will learn what an isotope is and how to write the correct symbols and names of various isotopes. Procedure: Working with your partner(s), count the number of protons (red marbles), neutrons (blue marbles) and electrons (yellow marbles) in each baggie and enter the data in the table below. Use your periodic table to identify the element. Following the example of lithium isotopes given above, write the symbol and name of each isotope. Data Table: Bag # Protons Neutrons Electrons Atomic Mass (ave. atomic mass) Isotope Mass Atomic Number Nuclear Symbol Isotope Name Ex. A Li Lithium-6 Ex. B Li Lithium

5 Questions: 1. What are some uses of isotopes? 2. How many hydrogen isotopes did you find? a. How are they the same? b. How are they different? 3. How many neutrons does 8 17 O have? 4. What is the correct nuclear symbol for carbon-14? 5. What does the 35 in the name chlorine-35 represent? 6. Cobalt-60 is used as radiation therapy for cancer. How many protons and neutrons does cobalt-60 have? 7. Iodine-131 is used to detect thyroid problems. How is iodine-131 the same as iodine-126? 8. How is iodine-131 different from iodine-126? Summary Paragraph: Write a paragraph summarizing what you learned in today s activity about isotopes. Explain what an isotope is and how different isotopes of one element are alike and different.