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Printable 9th grade fill-in-the-blank worksheet on nuclear fusion, energy, hydrogen, and helium in the sun.
Worksheet

Nuclear Fusion

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This printable science worksheet gives 9th graders seven fill-in-the-blank questions about nuclear fusion in the sun. Students learn how gravity and pressure cause hydrogen atoms to collide and turn into helium, releasing the energy that sustains life on Earth. Designed to accompany NASA Space Place's video "Where Does the Sun's Energy Come From?"

Subject:
Science
Topic:
Astronomy
Grade Level:
9th Grade
Updated August 2026

Word Bank

  • energy
  • Hydrogen
  • heat
  • Helium
  • nuclear
  • fusion
  • collide
  • gravity
  • pressure

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Print this worksheet for classwork, homework, or independent practice. Click 'View Worksheet' to edit questions, adjust formatting, or add your own content before downloading.

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