How Stars Make Elements
Aligned to HS-ESS1-3 — Next Generation Science Standards.
What this lesson teaches
Stars are element factories. Fusion in their cores builds heavier elements from lighter ones, up to iron. Elements heavier than iron form in the extreme heat of exploding stars, so every atom of gold or silver on Earth was once inside a dying star.
Worked example
A massive star fuses hydrogen to helium, then helium to carbon and oxygen, layer by layer, until its core is iron. When it can no longer fuse iron for energy, the star collapses and explodes as a supernova, forging and scattering elements like copper and uranium.
Practice questions
- Observe: The calcium in your bones and the iron in your blood are on the periodic table. What does their presence on Earth imply about where they were made?
- Model: Draw a large star as onion-like shells and label which elements fuse in each layer inward toward the iron core.
- Explain: Elements heavier than iron are rare compared to lighter ones. Use what you know about supernovas to explain why.
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
Cómo las estrellas crean elementos
Las estrellas son fábricas de elementos. La fusión en sus núcleos construye elementos más pesados a partir de más ligeros, hasta el hierro. Los elementos más pesados que el hierro se forman en el calor extremo de estrellas que explotan, así que cada átomo de oro o plata en la Tierra estuvo dentro de una estrella moribunda.
Ejemplo: Una estrella masiva fusiona hidrógeno en helio, luego helio en carbono y oxígeno, capa por capa, hasta que su núcleo es hierro. Cuando ya no puede fusionar hierro para obtener energía, la estrella colapsa y explota como supernova, forjando y dispersando elementos como el cobre y el uranio.
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