Interstellar medium

High school (ages 12+)
Space & Astronomy

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/interstellar-medium

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. How heavy is Interstellar medium?About 70% hydrogen, 28% helium, and 1.5% heavier elements by mass
2. What is the density range?Varies from ~100 ions/m³ (hot ionized medium) to >10^12 molecules/m³ (molecular clouds)
3. What does the interstellar medium look like?It isn’t empty; it contains clouds of gas and dust that glow or absorb light. Some parts are hot and ionized, while others are cold and dense. The different temperatures and densities give it a layered, dynamic appearance.
4. Why is the interstellar medium important for stars?Stars form inside the densest parts of the interstellar medium called molecular clouds. After stars die, they return heavier elements to the medium, helping new stars grow and keeping the galaxy evolving.

Plasma: A state of matter consisting of ionized gas, where electrons are stripped from atoms, common in the ISM.
Galactic Chemical Evolution: The process by which the abundance of chemical elements in a galaxy changes over time due to stellar nucleosynthesis and gas exchange.
Heliosphere: The vast bubble of charged particles created by the Sun that surrounds our solar system, marking the boundary before the ISM.