2. A Presentation on Stars
Created by Nicholas tang

4. What are stars?
Stars are big luminous balls of gas in outer space (you can see them in the sky at night) made of mostly hydrogen and helium. They shine by burning the hydrogen into helium then releasing the energy that radiates into outer space. They can burn the hydrogen to helium without the need for oxygen. The nearest star to earth is the Sun
Stars are held together by their own gravity. That’s how they turn from a nebula into a protostar.
Stars shine for most of their lives due to thermonuclear fusion of hydrogen into helium in its core.

5. What kinds of stars are there?
Stars start off small and grow bigger as they age. When stars are born, they start off as small dwarf stars, up to 20 times bigger than our sun and up to 20,000 times brighter. Our sun is a young dwarf star.
The next type of stars are Red Giants. A red giant or supergiant star is a star whose diameter is about 100 times bigger than it was originally and had become cooler.
A supergiant is the largest known type of star; some are almost as large as our entire solar system. Betelgeuse and Rigel are super giants. When super giants die, they turn into black holes

6. What type of star is our sun and how does it compare to the other stars in the same category?
Our star is a type G2V dwarf star and it is pretty small compared to other dwarf stars. Other dwarf stars can be up to 20,000 times bigger than our sun -

7. How are stars categorized?
Stars are classified by the elements that they absorb and their temperature. There are seven main types of stars, from highest to lowest temperature, O, B, A, F, G, K, and M
O and B stars are uncommon but very bright; M stars are common but dim
Our sun is in the middle of the scale, it is a G2V type star, a yellow dwarf and a main sequence star

8. Life cycle of a star
Stars are formed in clouds of gas(hydrogen) and dust, known as nebulae. Nuclear reactions at the center of stars provides enough energy to make them shiny brightly for many years.
The exact lifetime of a star depends on its size. Very large stars burn their fuel much faster than smaller stars and may only last a few hundred thousand years. Smaller stars, however, will last for several billion years because their burn their fuel much more slowly.

9. Life cycle of a star (cont.)
Over time, stars will expand, cool and change colour to become red giant stars. The path they will follow beyond depends on the mass of the star.
Small stars, like the Sun, will undergo a relatively peaceful and beautiful death that sees them pass through a planetary nebula phase to become a white dwarf.
Massive stars, on the other hand, will experience a most energetic and violent end, which will see their remains scattered about the cosmos in an enormous explosion, called a supernova. Once the dust clears, the only thing remaining will be a rapidly spinning neutron star, or possibly even a black hole

10. 20 Question test
Label the main classification of stars, from highest to lowest
1- O
2- B
3- A
4- F
5- G
6- K
7- M
What are Stars?
What are they made of?
What do they burn?
What kinds of Stars are there?
What are the biggest stars?
What are the smallest stars?
What are the brightest stars?
What are the Dullest Stars
How are stars born?
How do stars die?
Which stars live longer?
What happens when supergiant stars die?
Stars are not solid so how do they not fall apart in space?
Do stars get warmer or cooler as they grow older?
Label the life cycle of an average star
1- Nebula
2- Average Star / Main Sequence
3- Red Giant
4- Planetary Nebula
5- White Dwarf

12. Thank you for completing this PowerPoint!