Stars and Galaxies

What are stars made of, and what is a galaxy?

An exploration of the composition of stars and the structure of galaxies, designed for 10-year-olds.

Check your understanding

1. What are the two main gases that stars are made of?
- A. Oxygen and Carbon
- B. Hydrogen and Helium
- C. Nitrogen and Oxygen
- D. Helium and Carbon
2. What is the name of our home galaxy?
- A. The Milky Way
- B. The Spiral Way
- C. The Big Pinwheel
- D. The Solar Galaxy
3. What process inside a star creates its light and heat?
- A. Cooling down
- B. Spinning fast
- C. Nuclear fusion
- D. Atmospheric pressure
4. Which color star is the hottest?
- A. Red
- B. Yellow
- C. Blue
- D. White

1. Why do stars appear to 'twinkle' when we look at them from Earth?
- A. Because they are changing colors
- B. Because they are spinning very fast
- C. Because the Earth's atmosphere bends their light
- D. Because they are constantly exploding
2. If you saw a galaxy shaped like a smooth, stretched-out egg, what type would it be?
- A. Spiral
- B. Elliptical
- C. Irregular
- D. Pinwheel
3. Why don't stars usually hit each other when two galaxies collide?
- A. Because galaxies are made of invisible gas
- B. Because stars have strong magnetic shields
- C. Because gravity keeps them at a distance
- D. Because the space between stars is very large
4. Which statement best describes the relationship between stars and galaxies?
- A. Stars are bigger than galaxies
- B. Galaxies are cities made of billions of stars
- C. Stars live outside of galaxies
- D. Galaxies are made of only one single star

Watch the lesson, take the quiz, and ask a safe AI tutor anything about it.