Galaxies: Islands of Stars

What You'll Learn

Galaxies are enormous collections of stars, gas, and dust held together by gravity. Our Milky Way galaxy contains hundreds of billions of stars and is a spiral galaxy.

Key Words

planet
asteroid

Materials Needed

ruler
compass
black paper

Safety First

Tie back long hair before starting the experiment.
Protect your work surface with newspaper or plastic.

Steps

Step 1 — Read

Read the introduction and identify the main idea of this lesson.

Step 2 — Do

Build a scale model of the inner solar system using different-sized balls. Research the relative sizes and distances of the planets.

Step 3 — Observe

Observe what happens and describe it in detail.

Step 4 — Record

Record your observations in your science journal with measurements and descriptions.

Check Your Understanding

Question 1

1 of 3

What is a galaxy?