1st Quarter Lesson about Stars PDF

GOOD MORNING!  PRAYER “Dear Lord and Father of all, Thank you for today. Thank you for ways in which you provide for us all. For Your protection and love we thank you. Help us to focus our hearts and minds now on what we are about to learn. Inspire us by Your Holy Spirit as...

GOOD MORNING!  PRAYER “Dear Lord and Father of all, Thank you for today. Thank you for ways in which you provide for us all. For Your protection and love we thank you. Help us to focus our hearts and minds now on what we are about to learn. Inspire us by Your Holy Spirit as we listen and write. Guide us by your eternal light as we discover more about the world around us. Amen.” CHECKING OF ATTENDANCE MYSTERY Box Game Keep / Give The Box?  HOW TO PLAY: Make 2 teams Pick a letter and answer the question Then you must choose: KEEP THE BOX or GIVE THE BOX to the other team  BE CAREFUL! The points in the box can be GOOD or BAD LIFE CYCLE OF A STAR  LEARNING OBJECTIVES explain how describe the explain how stars are different the mass in a formed and stages of a star affects their life cycle star’s life the star’s life span span  STARS Stars have a life-cycle. The Sun is a main sequence star which means it is in the middle of its life. Stars begin as a cloud of gas and dust, brought together by gravity. This cloud is called a nebula.  GRAVITY Gravity causes the dust cloud to become more hot and more dense. It has now become a protostar. Eventually, the temperature and pressure become high enough that hydrogen nuclei undergo fusion and become helium nuclei. The fusion reactions release large amounts of energy to keep the core of the star hot.  PROTOSTAR The protostar then becomes a main sequence star. In main sequence stars, the outward pressure caused by the fusion reaction is balanced with the gravitational force caused by the mass of the star. Stars usually remain in the main sequence for several billion years. A nebula condenses and takes on a shape it is called P rotostar.  If the star is the size of the Sun or less, it becomes unstable and expands, forming a red giant. The star then ejects its outer layers and becomes a white dwarf, which is the small, hot core of the star. Finally the white dwarf cools into a black dwarf. WHAT ARE THE DIFFERENT STAGES IN STAR'S LIFE CYCLE?  STELLAR NEBULA Stars form inside nebulas because nebulas contain lots of hydrogen, the gas stars are mostly made of. Within nebulas, gravity pulls clumps of hydrogen together. Because the gravity of any object, including a ball of hydrogen, grows as it gets bigger, those clumps start attracting more and more gas. Over long periods of time, they draw so much gas to themselves that they become round and condense into a protostar.  PROTOSTAR A protostar looks like a star but its core is not yet hot enough for fusion to take place. The cloud begins to glow brightly. At this stage, it contracts a little and becomes stable and is called a main sequence star. MAIN SEQUENCE STAR A star will remain in this stage, shining for millions or billions of years to come. In main sequence stars, the outward pressure caused by the fusion reaction is balanced with the gravitational force caused by the mass of the star. As the main sequence star glows, hydrogen in the core is converted into helium by nuclear reactions. PLANETARY NEBULA As a smaller star begins to cool down and lose its glow, it will eventually go through the planetary nebula stage.  WHITE DWARF White dwarfs are the dense, hot remains of stars that have already perished. A white dwarf is very hot when it forms, but because it has no source of energy, it will gradually cool as it radiates its energy away. This means that its radiation, which initially has a high color temperature, will lessen and redden with time.  BLACK DWARF A black dwarf is a kind of star. A black dwarf is made when a white dwarf star becomes too cold. When it is cold enough, it can no longer make large amounts of heat and light The star will get darker and become black. Scientists are not certain if black dwarfs can exist because it takes longer than the age of the universe (1 3.8 billion years) for a white dwarf to become one. LARGE STARS RED SUPERGIANT Red supergiants are much larger than red giants, and so appear much brighter. Red supergiants can occasionally contract because different elements in the core fuse at different rates. When they contract, they become hotter and therefore bluer, and they are then known as blue supergiants. WHAT DETERMINES IF A STAR BECOMES A BLACK HOLE OR NEUTRON STAR? Only one thing - the mass of the star. If the mass of the supernova remnant is below 2.1 6 times the mass of our Sun, it will collapse into a neutron star. If, however, the mass is more than this, then it will collapse into a black hole.  BLACK HOLE A black hole is an area of such immense gravity that nothing -- not even light -- can escape from it. Black holes themselves are invisible—they emit virtually no light and so cannot be seen directly. Black holes can grow more massive over time as they “eat” gas, stars, planets and even other black holes! LET’S TRY  Read and analyze the following questions carefully. Write the letter of the correct answer. 1. What is the primary factor that determines whether a star will become a white dwarf, neutron star, or black hole? A. The star’s temperature B. The star’s mass C. The star’s color D. The star’s age 2. Cooler stars appear to be what color? A.Red B. Yellow C.Blue D. Green 3. A protostar develops in a nebula as ________ causes the gas and dust to pull together. A.Gravity B. Temperature C. Mass D. Size  4. What stage follows a red giant in the life cycle of a medium-mass star like the Sun? A.Black Hole B. White Dwarf C. Supernova D. Neutron Star 5. Which type of star is the hottest in the main sequence stage? A.Red dwarf B. Blue giant C.Yellow dwarf D. White dwarf  TAKE AWAYS/ LEARNINGS Direction: Choose any from the word below and use it in a sentence to sum up today’s lesson. Protostar Star Gravity THANK YOU! I hope you learn something new today!