Learning Outcomes 2. Key Concepts 2. Misconceptions and Teaching Challenges 3. Vocabulary 3. Lesson and Content Overview 5

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1 UNIT 2 GUIDE Table of Contents Learning Outcomes 2 Key Concepts 2 Misconceptions and Teaching Challenges 3 Vocabulary 3 Lesson and Content Overview 5 BIG HISTORY PROJECT / UNIT 2 GUIDE 1

2 Unit 2 The Big Bang Unit 2 Driving Question: How and why do individuals change their minds? Learning Outcomes 1. Explain the basics of the Big Bang theory and the primary evidence that supports this theory. 2. Using evidence from texts, explain why views of the Universe have changed over time and the roles that scientists have played in shaping our understanding of the origin of the Universe. 3. Understand how to use claim testing to evaluate a claim or resource. Key Concepts How have our views of the Universe developed and changed over time? After they ve examined that topic, students will learn about the basic building blocks of everything around us by understanding what appeared in the first moments after the Big Bang. They ll then learn how the early Universe evolved as it expanded and cooled. They ll hear the story of the first half million years of the Universe s existence and study some of the evidence that has convinced astronomers that this story is correct. This unit discusses topics normally studied within the disciplines of cosmology and nuclear physics. Students also will learn about the process of claim testing, which will help them evaluate claims and resources throughout the course as well as in other aspects of their lives. The Big Bang The appearance of the Universe in the Big Bang is the first threshold of increasing complexity. Before this moment, nothing existed; after it, something new existed: the Universe! The Big Bang provided the raw materials for everything around us today. Following the Big Bang, there was space, which rapidly expanded. There were also time, matter, and energy. Energy took different forms and matter appeared in the form of electrons and quarks, which soon linked together to form protons and neutrons. Nothing had turned into something, and that something contained everything needed to build an interesting Universe. Claim Testing Big History doesn t just tell stories about the past; it also explores the evidence on which these stories are based and asks you to make your own judgment as to whether the stories should be trusted. The four main strategies we use for deciding if a story should be trusted, or whether something is true or not, are intuition, authority, logic, and evidence. The trouble with intuition (gut feeling), is that it s subjective. Although holding a strong belief that something is or isn t true might lead to promising avenues of research, by itself it proves nothing. Authority means simply that you trust someone to tell the truth. We can t test everything that s said and often we decide to believe someone because we think they know what they re talking about. Relying on authority is often necessary, but wherever possible, we should test the stories told to us. We can do that by using the last two strategies to answer these questions: Are the assertions or stories logical? Is there some clear, objective, testable evidence to support them? BIG HISTORY PROJECT / UNIT 2 GUIDE 2

3 Misconceptions and Teaching Challenges Vocabulary In Unit 2, the complexity of the vocabulary and concepts that students encounter are high. These concepts are often hard to grasp without the context of the expansion of the Universe. To help your students understand the concepts, consider doing three rather than two vocabulary activities in this unit. Devoting extra time to learning and conceptualizing terms will help students grasp some of the ideas in this unit more easily. Understanding the Unknown In Big History, students often struggle with the idea that we actually don t have answers to some of the questions they may have or that are raised by the course itself. This becomes apparent in this unit since we have no idea what happened before the Big Bang. It can be helpful to tell students that not knowing the answer to everything is one of the fun things about the study of history. We don t know everything about our past, but science and other disciplines can help us get closer to knowing. One day we might know what came before the Big Bang. Teaching Science Teachers often mention that they don t have the disciplinary knowledge to teach all the science that they are presented with in the first half of the Big History course. It s not just the science! It would be nearly impossible for anyone to know all of the content presented in Big History, not to mention to understand it from all of the different disciplinary perspectives. Remember that in Big History it s helpful to take on the belief that instead of being the traditional teacher, you are the lead learner in the classroom. You can find more information about this idea in the Teacher as Lead Learner Guide. Vocabulary astronomy The branch of science that deals with the Universe and the various objects, like stars, planets, and galaxies, that we find within it. Cosmology and astrophysics are closely related to astronomy, and the words are sometimes used interchangeably. Cosmology focuses on the Universe s largest scales in space and time, and astrophysics focuses on the properties and interactions of astronomical objects. atom A small unit of matter composed of protons, electrons, and usually neutrons. Atoms are basic building blocks of the matter we see in the Universe and on Earth. The number of protons in the nucleus of an atom determines which chemical element it is. authority A respectable or credible source; an expert. Big Bang A theory, first articulated in the 1920s, proposing that the Universe started out extremely hot and dense and gradually cooled off as it expanded. Cepheid A star that fluctuates in brightness and provides astronomers with a reference they can use to measure great distances in the Universe. It was the identification of Cepheids in nearby galaxies that first proved that the Universe consists of more than one galaxy. claim An assertion that something is true. BIG HISTORY PROJECT / UNIT 2 GUIDE 3

4 claim testing The use of strategies to decide whether a story or concept should or should not be trusted. The four strategies for claim testing that we use in Big History are intuition, authority, logic, and evidence. collective learning The ability to share, preserve, and build upon ideas over time. Cosmic Microwave Background (CMB) or Cosmic Background Radiation (CBR) Low-energy radiation pervading the entire Universe, released about 380,000 years after the Big Bang. At this point, the Universe had cooled sufficiently for atoms to form and allow radiation and matter to separate. cosmology The study of the Universe on its largest scales, including its origin and structure. Doppler effect The apparent stretching out or contraction of waves because of the relative movement of two bodies. The Doppler effect explains why an ambulance siren seems higher when the ambulance is traveling toward you than when it is moving away. It also helps astronomers identify whether objects such as stars or galaxies are moving toward us or away from us. electromagnetism One of the four fundamental forces or interactions, along with gravity, the weak nuclear force, and the strong nuclear force. Among other things, electromagnetism is responsible for the interaction between electrically charged particles, including holding electrons and protons together to form atoms. Electromagnetism is also responsible for essentially all molecular interactions. electron A negatively charged subatomic particle that orbits the nucleus of an atom. energy The capacity to do work, associated with matter and radiation. Includes kinetic energy, potential energy, and chemical energy, among others. evidence Concrete, verifiable information that either supports or disproves a claim. gravity The fundamental force of attraction between any two objects that have mass. helium The second simplest of all chemical elements, helium has two protons and (almost always) two neutrons. Helium was produced soon after the Big Bang. hydrogen The simplest of all chemical elements, hydrogen has one proton. Hydrogen was the first element produced after the Big Bang and is the most common element in the Universe. inflation The idea that space and time (space-time) underwent an expansion at a rate much faster than the speed of light during the first seconds after the Big Bang. intuition A gut feeling that is not necessarily based on logic or evidence. light-year A measure of distance in space; the distance that light travels in a vacuum in one year. It is equal to roughly 9.5 trillion kilometers, or 5.9 trillion miles. logic The application of systematic reasoning to arrive at a conclusion. matter The physical material of the Universe, including subatomic particles, atoms, and the substances that are built out of them. neutron An electrically neutral subatomic particle present in the nuclei of most atoms. Unlike protons, the number of neutrons in a given element can vary, giving rise to different isotopes of an element. nucleus (atomic) The extremely dense and positively-charged region at the center of an atom that consists of protons and neutrons. BIG HISTORY PROJECT / UNIT 2 GUIDE 4

5 parallax The change in the apparent position of an object caused by movement of the observer. proton A subatomic particle with a positive electric charge. The number of protons in an atom (the atomic number) determines which element it is: For example, carbon atoms always have 6 protons, while iron atoms always have 26 protons. redshift The phenomenon in which light waves from distant galaxies are stretched out, which for visible light means a shift toward the red side of the spectrum. Redshift provides scientists with strong evidence that the Universe is expanding, since the expansion of space explains the stretching of the light waves. scientific method The process of gathering evidence to test and refine scientific theories. space-time The unification of space and time into a single four-dimensional continuum or fabric. Space makes up three of the dimensions, while time makes up the fourth, and cannot be fully separated from space. Albert Einstein s General Theory of Relativity holds that all objects with mass interact with space-time by bending it much like a person standing on a trampoline bends the trampoline. telescope An instrument used for viewing distant objects, including planets, stars, and galaxies. thermodynamics (first law of) One form of the law of conservation of energy, which states that energy may change forms but cannot be created or destroyed. Lesson and Content Overview Lesson name Lesson description Content Activity 2.0 How Did Our Understanding of the Universe Change? Does the Sun revolve around the Earth? Wait that doesn t sound right. Astronomers have used the tools of their time to understand the Universe, each generation building on the theories of the one before them. Watch: How Did Our View of the Universe Change? Read: Changing Views Opening: DQ Notebook Vocab Activity: Memorization Activity: Views of the Universe Debate Closing: Compare/Contrast Essay 2.1 The Big Bang The Big Bang is where big history begins. Everything that s ever existed including you traces back to this unimaginably profound event. Watch: A Big History of Everything: A Brief Big History H2 Watch: Threshold 1: The Big Bang Watch: Questions About the Big Bang Watch: Electromagnetism: A Brief Big History H2 Opening: Big Bang Snap Judgment Vocab Activity: Comprehension/Application Activity: This Threshold Today Closing: Big Bang Infographic 2.2 Claim Testing How do you decide what to believe? If you read it on the Internet, does it have to be true? How about something your doctor tells you? Claim testing helps us assess the trustworthiness of information. Read: Approaches to Knowledge Watch: How Do We Decide What to Believe? Read: The Claim Testers: Episode 1 First Contact Opening: Claim Testing Snap Judgment Activity: DQ Notebook Activity: Claim Testers and Discussion Closing: Investigation 2 BIG HISTORY PROJECT / UNIT 2 GUIDE 5

6 Lesson name Lesson description Content Activity Investigation: How and why do individuals change their minds? This investigation, required as a baseline writing assessment, is focused on how and when scientists change their minds. Geocentric view Heliocentric view Scientific writings by Galileo and Copernicus Investigation Writing Claim Testing Worksheet Additional content Additional content items, including image galleries, can be used to augment lessons or customize your own unit. How Our Understanding of the Universe Changed (gallery) What Emerged from the Big Bang (video) The Structure of Scientific Revolutions (article) Henrietta Leavitt (article) Tycho Brahe (article) Science, Theology & the Copernical Revolution (article) The Vatican Observatory (article) Learning tips Random facts Related galleries, images, websites, and videos Web links Assessments Unit 2 includes lesson and glossary quizzes. Also included is a required Investigation writing assessment, the first of three such assessments in the course. Lesson Quizzes Glossary Challenge Investigation Writing Actions The Unit Log is required for every unit. Unit Log BIG HISTORY PROJECT / UNIT 2 GUIDE 6

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