The Life Cycle of Stars

Lab Brief #3

🎯 Your mission

Master the concept. Use it tomorrow.

⚡ The twist

The light you see now started its trip a long time ago.

What you'll learn

Stars form when gravity collapses a nebula until fusion ignites. A star like the Sun spends billions of years on the main sequence, swells into a red giant, then sheds its layers to leave a white dwarf. Much heavier stars end as supernovae, leaving neutron stars or black holes.

Key words

main sequence
The long stable phase in which a star fuses hydrogen into helium in its core.
supernova
The explosive death of a massive star, scattering heavy elements into space.

Make a hypothesis first

Guess: how big does that look from here vs. from there?

Say your guess out loud — then find out if you were right.

Step 1 of 4 · Read

Think about what you just learned: say what "main sequence" and "supernova" mean in your own words before you start.

Step 2 of 4 · Do

Draw two parallel flowcharts, one for a Sun-mass star and one for a star twenty times heavier, labelling every stage and the force balance that ends it. Mark where the elements in your own body were made.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 2

A star spends most of its life:

How sure are you?😐 maybe

Question 2 of 2

Elements heavier than iron are formed mainly in:

How sure are you?😐 maybe

Mind = blown

🌌 If you could drive a car straight up at highway speed, you'd reach space in under an hour.

Nice work!

You got 0 of 2 right.

Next: Redshift and the Expanding Universe All lessons

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✨ More to explore

🌍 Where you see this in real life: Every sunrise and every shadow is this idea in action.

🏆 Stretch challenge (try it this week): Look at the moon tonight. Notice its shape. Look again in 3 days.

👨‍👩‍👧 For the dinner table: “If you could visit any planet, which would you pick and why?”

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