Stars and Brightness — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
Stars are made of solid rock like Earth.
Corrected: Stars are made of hot, glowing gases like hydrogen and helium.
Stars are giant balls of plasma, mostly hydrogen and helium, fused together to make light and heat.
2. Fix the sentence:
All stars are the same size and brightness as our Sun.
Corrected: Stars come in many different sizes and brightnesses.
Some stars are smaller and dimmer than the Sun, while others are far larger and much brighter than it.
3. Fix the sentence:
Stars only shine at night, then they go to sleep during the day.
Corrected: Stars shine all the time, but daylight from the Sun hides them.
Stars constantly produce light. Sunlight scatters across our blue sky and hides their faint glow.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. A star is a huge ball of hot, glowing gas in space.
Stars produce their own light and heat through nuclear reactions deep within their hot cores.
2. When Earth turns away from the Sun, we experience night.
As Earth rotates, the side facing away from the Sun is dark, allowing distant starlight to be seen.
3. The Sun is the closest star to our planet Earth.
At 93 million miles away, the Sun is far closer than the next star, Proxima Centauri.
4. Stars twinkle because Earth's atmosphere bends their light.
Moving air pockets in our atmosphere bend starlight, making distant stars appear to twinkle to our eyes.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Why can we see many stars at night but not during the day?
Sample answer: At night, our side of Earth faces away from the Sun, so the sky is dark and faint starlight becomes visible.
Sunlight scatters in air and overpowers stars during the day, but darkness lets faint starlight reach us.
2. How is the Sun the same as the stars we see at night?
Sample answer: The Sun is a star, just like the ones we see at night. It only looks bigger because it is much closer to Earth.
All stars are hot balls of glowing gas. The Sun seems special only because we live so close to it.