Read the Following Selection
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A Star Is Born
We need light to see. Light can be natural (from nature) or artificial (made by people). The most important source of natural light is our Sun. Our Sun makes its own light just like all stars in the sky. But where do stars come from?
A Star Nursery
Stars are born in a star nursery called a nebula. Stars are made from gases and dust. In the nebula, the gases and dust come together to form a core, or centre. The core gets bigger and bigger, and the baby star gets hotter and hotter. When it is hot enough, the star begins to burn a gas called hydrogen. It is the burning of hydrogen that produces light, heat, and energy.
Stars Get Older
These baby stars grow, just like you do. Some stars are smaller than others. Our Sun is an average-sized star, called a yellow dwarf star. These stars give off light that is white to light yellow. This light becomes brighter as the stars get older.
Smaller stars last longer than bigger stars. Yellow dwarf stars can last for 10 billion years. Then they start to get bigger. The temperature gets cooler and the light they give off looks red. They become red giant stars.
Our Sun is about halfway through its life, so it will not become a red giant for billions of years yet.
The End of a Star
Near the end of its life, a red giant star will collapse and become much, much smaller. It will also get much cooler and the light it gives off will not be very bright. It is now a white dwarf star. In time, white dwarf stars become invisible because they give off so little light.
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1. What are stars made from?CorrectIncorrect
2. What happens to a baby star as its core gets bigger?CorrectIncorrect
3. Which star is the smallest?CorrectIncorrect
4. What is the difference between natural light and artificial light? What are some examples of natural light? What are some examples of artificial light?
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5. How does our Sun produce light?CorrectIncorrect