The Life Cycle of a Star A PROJECT BY ALEXANDRA FULLER
PART I: THE BIG BANG
Chapter 1: The Universe Starts
The Universe started with what scientists theorized is called "The Big Bang". The Big Bang was a large explosion in empty space that caused hydrogen and helium atoms to spread throughout the universe, and the hydrogen and helium began to combine after a while, forming new elements.
WHERE DO ELEMENTS COME FROM, AND WHAT ARE THEY? An element is a substance that consists of one type of atom. There
are currently 118 elements on the periodic table, which shows the different elements and the different
parts of elements. When the universe first started, there were only two elements; hydrogen and helium. These elements were formed after the Big Bang.
Part ii and iii
Part iv What 3 pieces of evidence do we have for how the universe formed? HYDROGEN + HELIUM
There is a particular amount of hydrogen and helium in the universe showing that it all came at once at one point, during the Big Bang.
HUBBLE' S LAW The universe is still expanding, and we can see it through Red Shift.
COSMIC BACKGROUND RADIATION There is a type of radiation known as cosmic background radiation, and it is everywhere in the universe. It is the energy left bhind after the Big Bang.
CHAPTER 2 PART I WHEN AND HOW DID STARS FORM? Stars first formed when the universe was about 200 million years old. Stars are formed by intense heat and pressure. Gravitational pull forces gas and dust to begin being forced together. The gas and dust being forced together by the pressure begins to heat up, and eventually forms the core of a star. The heat of fusion within the core forces energy outward, and the outward pressure keeps the star from collapsing in on itself due to the pressure pushing in.
PART II AND III WHAT IS NUCLEAR FUSION, AND HOW DOES IT FUEL STARS? HOW DOES IT WORK, WHAT DOES IT REQUIRE TO WORK, AND WHAT IS MADE BY IT?
Nuclear fusion is hydrogen (one proton) atoms fusing with other hydrogen atoms (also one proton) to create helium (two protons) atoms. Nuclear fusion requires intense heat and pressure in order to occur. Nuclear fusion works by releasing energy in the form of gamma radiation(a high frequency form of energy that is invisible to the human eye, and can be damaging to living organisms), and the energy travels outwards, which keeps the outside pressure of the star's gravitational force from pushing the star inward and causing it to collapse. The energy keeps the star alive. Nuclear fusion can occur with any
Chapter 3 Part i How do we gain elements larger than iron? They are formed in extremely large stars, and then released in supernovas, and spread throughout the universe. They require high amounts of heat and pressure.
Part ii How do stars change over the course of their life cycle?
The star will fuse elements within the core, keeping the star alive. The
elements will continue fusing together and generating energy until it reaches iron(Fe, 26 protons). When the star begins running out of energy, the core begins collapsing in on itself, and it
becomes hotter. Larger stars will last a shorter amount of time than smaller stars, while smaller stars will last longer than larger stars.
Part iii What decides or influences the life cycle of a star?
The life cycle of a star depends on the size of the core. If the star's core is smaller(compared to other stars), then it will have a longer lifespan, and when it dies, it will turn into a white dwarf star, which is very small for a star. The white dwarf will then eventually cool down, and turn to nothing. Stars with larger cores will most likely experience a nova, where only the outer layer explodes, or supernova, where the star will completely implode(crush in on itself and then explode). And if the supernova is big enough, it will turn into a black hole. They are the densest object in the universe, and their pull of gravity is so great that anything that enters it will never be seen again, not even light.
Chapter 4 Part i How do we determine the composition of stars and other objects in space? Star composition is discovered through the spectrum of visible light. Using a tool called a spectroscope, we can see the different light emitted by burning atoms. Each different atom gives off a different light or spectrum. Stars give off waves that can be shown as visible light through a spectroscope. and with that, you can figure out what elements are burning within a star.
MR. ADAMS' GOOGLE CLASSROOM https://classroom.google.com/c/MjA5MzEzNzE5MDZa
NASA Source 1: NASA - Spectral Analysis. imagine.gsfc.nasa.gov/features/yba/M31_velocity/spectrum/spectra_info.html. Source 2: When did the first stars form in the universe? - StarChild - NASA. starchild.gsfc.nasa.gov/docs/StarChild/questions/question55.html.
IMAGES FOUND ON GOOGLE OTHER INFO KNOWN FROM PRIOR KNOWLEDGE