Galaxies and the Milky Way

In this lesson, Miss Friedman introduces the concept of galaxies to grade 7 students. The lesson begins with a recap of gravity and moves on to define galaxies, highlighting the four types: spiral, irregular, elliptical, and lenticular. The focus is on spiral galaxies, particularly the Milky Way, which is our galaxy. The lesson covers the historical discovery of galaxies and provides a detailed look at the Milky Way's structure. Students are encouraged to observe the Milky Way from Earth and are left with a fun fact about the vast number of galaxies in the universe.

What was the main topic discussed in the previous lesson?

• The structure of the Milky Way

• The force of attraction known as gravity

• The types of galaxies

• The history of astronomy

How is a galaxy defined?

• A group of planets orbiting a star

• A collection of stars, planets, gas, and dust

• A cluster of black holes

• A single star with its planets

Which of the following is NOT a type of galaxy?

• Spiral

• Irregular

• Circular

• Elliptical

What is the most common type of galaxy?

• Lenticular

• Elliptical

• Irregular

• Spiral

What is the name of our galaxy?

• Andromeda

• Whirlpool

• Triangulum

• Milky Way

What were spiral galaxies originally called?

• Spiral clusters

• Spiral nebulae

• Star clouds

• Gas clouds

Where is the sun located in the Milky Way?

• In the nucleus

• In one of the spiral arms

• Outside the galaxy

• At the center

What is the nucleus of the Milky Way?

• A type of star

• A cluster of planets

• The center of the galaxy

• The outermost layer

How can we identify the Milky Way from Earth?

• By finding a large planet

• By seeing a rainbow

• By observing a cluster of clouds and stars

• By looking for a single bright star

Approximately how many galaxies are believed to exist in the universe?

• 200 billion

• 1 trillion

• 500 thousand

• 100 million