Objectives

Lesson outcomes

  • Describe how spectral lines from distant galaxies are shifted to longer wavelengths and identify this as redshift.
  • Use the redshift relation to calculate recessional speed for a distant source.
  • Explain how redshift evidence supports the idea of an expanding universe.
  • Use Hubble's law to relate recessional speed to distance and connect that pattern to the Big Bang model.
Syllabus

CIE 9702 syllabus points

4 linked

Lesson Notes

Student guidance and lesson notes

Overview

Use redshift evidence and Hubble’s law to describe the expanding universe. Use this page for class notes, worked examples, and linked resources.

What You Need to Know

  • Use redshift evidence and Hubble’s law to describe the expanding universe.
  • Identify the key definitions, models, equations, or diagrams for this lesson.
  • Use at least one worked example, observation, or practical link to make the idea concrete.

How to Work Through It

  1. Start with the prior knowledge, context, or recall questions for this lesson.
  2. Work through the main explanation, method, diagram, or calculation for this lesson.
  3. Complete the guided practice, discussion, calculations, or practical application.
  4. Review your learning with an exit prompt, short question, or summary task.

Check Your Understanding

  • Can you answer a checkpoint question aligned to the main objective(s)?
  • Can you give a short verbal, written, or numerical response that shows secure understanding?

Common Mistakes

  • Watch out for the likely misconception, error, or weak step in this lesson.
  • Use the comparison, model answer, or explanation that corrects it.

Next Steps

  • Complete the homework, retrieval task, or resource revisit linked to this lesson.
  • Note what you need to carry forward into the next lesson.
Lesson Resources

Materials for this lesson

Use these videos, slide decks, documents, or links to work through the lesson.

Worksheet

Orbiting binary stars - Practice Questions + Solutions

Orbiting binary stars - Practice Questions + Solutions

Open resource