The main topic of this semester was informative writing and we wrote a informative paper. My paper was about the life cycle of stars, and i think the topic really helped me improve writing this kind of papers.
what was the biggest success?
I think the procedure of having research notecards is very helpful, and so it was easy to write the actual paper. therefore i think that my biggest success was easily writing the paper, looking at the research notecards that i made.
what was the biggest difficulty?
My biggest difficulty was doing research. The information from the internet was very mixed up, and the information itself was very hard to understand and learn. I eventually learnt them but i felt like i took extra science classes! But after doing all the research, it was easy to write the actual paper.
what would you have done difficultly?
If I were to write another research paper, I would choose a easier subject to learn, yet which has a lot of information on the internet. Also, i will try to look for more reliable sources to successfully cite them.
My research paper:
In the sky, there are more than 100 billion stars, but none of them are the same. Some shine brighter, some are larger and hotter. They might be different because of their surroundings, for example, temperature differences or number of asteroids etc. But stars, like living things, also has a life cycle which changes their form through time.There are two different life cycles of stars, each with 5 stages. They both share the first stage, and develops their own cycles depending on their mass.
The destiny of the two stars lie on their birth from the clouds of dust , which is called a nebula. The first stage of a star is called a protostar. “A star begins its life as a cloud of gas, which is mostly hydrogen and helium. The particles experience a very weak attraction towards each other due to gravity. As the gas cloud becomes denser, the effect of gravity is to increase the pressure and temperature. As more gas is drawn in by the increasing gravity, the mass of the cloud increases and therefore so does its gravity.The increasing gravity compresses the gas further so that it becomes hotter and denser. It eventually becomes a protostar(NASA).” The protostar’s mass depends on how much resource is around the star because the more resource it collects and gathers, the higher the mass of the star becomes. There are two main types of stars, low mass stars and high mass stars(Khan).
The low mass stars live for a long time compared to the high mass stars. After being a protostar, the next step of the low mass star is a main sequence star: “the protostar changes into a main sequence star, which is the second major step of a star. The core fuses hydrogen and helium together, and keeps on burning(Space).” It spends 90% of it’s lifetime as a main sequence star until the core is hot enough to fuse helium into carbon, which is a heavier element. The energy produced by this process makes the star grow many times bigger than it’s normal size. This is the third step of a low mass star, called the red giant(@NolaTRedd). When the star gets too hot and large, the outer layer of the star blows off while the core shrinks to a white dwarf. The outer layer creates a large cloud of dust around the core. This is called is a planetary nebula, which is a minor conversion step form the red giant to white dwarf. The star stays as a planetary nebula for thousands of years(Ask). The white dwarf is typically made of carbon and oxygen(Khan). The white dwarf is still bright, but it doesn’t fuse elements anymore, causing it to cool down, becoming a black dwarf which doesn’t give light out. The universe’s existence is too short to prove the existence of the black dwarf. The black dwarf is the last stage of a star, and expels matter that forms a nebula, waiting to become a new star in the future(NASA).
High mass stars have a very short lifespan, living one to ten million years. High mass star’s second stage is also a main sequence star, but heavier and larger than the low mass main sequence star. It lives 90% of it’s life as a main sequence star then it becomes a huge star called a supergiant when it starts to produce heavier elements like iron. The star lives as a supergiant for 10% of it’s lifetime(@skyandtelescope). But because the star is too unstable due to its large mass and size, the outer shell explodes into a huge cloud of dust. “A supernova is an explosion of a massive supergiant star. It may shine with the brightness of 10 billion suns! The total energy output may be 1044 joules, as much as the total output of the sun during its 10 billion year lifetime.(NASA)” After this, the star’s core collapses into it’s own gravity because of its unstable state, gradually becoming compact until it’s mass is so high despite it’s size. It becomes a black hole. Not many stars become a black hole because they need to be very large to become one. The gravity is so strong that light cannot escape from it(Dunbar). But black hole is not the only choice, when they have a slightly lower mass to become a black hole, but still has a very large mass, they become a neutron star, which is very dim because it does not fuse any elements anymore.“When a star becomes a supernova, part of its original magnetic field is ejected in the gas that is ejected by the explosion. But some of the field, trapped as it is by its connection with charged plasma, collapses into the core of the star which is imploding to become the neutron star(Pulsar).” high mass star’s life cycle normally ends in the stage of a supernova and become nebula, but when they become a neutron star or a black hole, they last so long that there are only theories of how they die.
The life cycle of stars are very long. Low mass stars and high mass stars start as a protostar and becomes a main sequence. Then the low mass stars become a red giant, then a planetary nebula, white dwarf and a black dwarf in order. The high mass star become a supergiant, supernova, then either a black hole or a neutron star. But almost none of the 100 billion stars actually finished their life cycle, and there is no proof that the theories about them becoming a nebula again after death are true.