The Universe and Its Stars
Aligned to HS-ESS1 — Next Generation Science Standards.
What this lesson teaches
The universe began with the Big Bang and has expanded ever since. Stars form, fuse elements, and die, recycling matter into new stars and planets.
Worked examples
Example 1
Our sun fuses hydrogen into helium, releasing energy; when massive stars die, they scatter heavier elements that form planets like Earth.
Example 2
Nearly every atom in you heavier than helium was made inside a star. The calcium in your bones was forged in one that exploded.
Example 3
A star's mass decides its whole life. The most massive burn out in a few million years; small red dwarfs will still be shining in a trillion.
Practice questions
- What evidence supports the Big Bang?
- How do stars produce energy?
- Where did the heavy elements in Earth come from?
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
El universo y sus estrellas
El universo comenzó con el Big Bang y se ha expandido desde entonces. Las estrellas se forman, fusionan elementos y mueren, reciclando materia en nuevas estrellas y planetas.
Ejemplo 1: Nuestro sol fusiona hidrógeno en helio y libera energía; cuando las estrellas masivas mueren, dispersan elementos más pesados que forman planetas como la Tierra.
Ejemplo 2: Casi todos los átomos en ti más pesados que el helio se hicieron dentro de una estrella. El calcio de tus huesos se forjó en una que explotó.
Ejemplo 3: La masa de una estrella decide toda su vida. Las más masivas se consumen en unos millones de años; las enanas rojas pequeñas seguirán brillando dentro de un billón.
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