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Science lesson plan · 11th grade (Year 12 in England) · 45 minutes

The expanding universe and the Big Bang

Space

CCSS NGSS.HS-ESS1-2England: KS4 Physics: Space physics (separate science)

Objective and success criteria

Students will: The expanding universe and the Big Bang.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: The life cycle of stars; The electromagnetic spectrum

Leads to: the next skill in this area.

Materials: Torch and ball for a Sun-Earth-Moon model, Space images, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 5 min

  • Quick retrieval from earlier learning (The life cycle of stars; The electromagnetic spectrum). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. In the life cycle of a star much more massive than the Sun, what comes straight after "supernova"? (neutron star or black hole / red supergiant / main sequence star / nebula) → neutron star or black holePrompt: Very massive stars end their lives far more violently than the Sun.
  2. In the life cycle of a star like the Sun, what comes straight after "nebula (cloud of dust and gas)"? (main sequence star / white dwarf / protostar / red giant) → protostarPrompt: The Sun is in its main sequence stage now.
  3. In the life cycle of a star like the Sun, what comes straight after "protostar"? (nebula (cloud of dust and gas) / red giant / white dwarf / main sequence star) → main sequence starPrompt: The Sun is in its main sequence stage now.

Hook · 5 min

  • Ask why we see the Moon change shape over a month.
  • Share the objective: The expanding universe and the Big Bang. Read the success criteria together.

I do: model it · 10 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: About how old is the universe?
  • Step 1: Measurements of the CMB and expansion give an age of about 13.8 billion years.
  • Step 2: So the answer is: about 13.8 billion years
  • Answer: about 13.8 billion years
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 10 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. What is red-shift? (light becoming bluer / the Sun setting / galaxies turning red because they are hot / light from distant galaxies is stretched to longer wavelengths) → light from distant galaxies is stretched to longer wavelengthsPrompt: Red light has a longer wavelength than blue.
  2. The Big Bang: which statement is true? (The Earth is the centre of the universe. / The Big Bang was an explosion at one point in an existing empty space. / Red-shift means galaxies are moving towards us. / The cosmic microwave background is evidence for the Big Bang.) → The cosmic microwave background is evidence for the Big Bang.Prompt: Which way are distant galaxies moving?

You do: independent practice · 10 min

  • Students work on the student sheet. Circulate and check the first two answers of every student early.
  • Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

Exit ticket · 5 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. A spectral line normally at 656 nm is observed at 669.12 nm in light from a galaxy. By how many nanometres has it been red-shifted? → 13.12 nmPrompt: Find the difference between the observed and normal wavelengths.
  2. What is red-shift? (light from distant galaxies is stretched to longer wavelengths / light becoming bluer / galaxies turning red because they are hot / the Sun setting) → light from distant galaxies is stretched to longer wavelengthsPrompt: Red light has a longer wavelength than blue.

Watch out for

  • Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
  • Remembering facts without the reason: ask "why?" and "what is the evidence?"

Support and stretch

Support

  • Review first: The life cycle of stars.
  • Use concrete materials: torch and ball for a sun-earth-moon model.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-11.

Free lesson plan from eurekami.com/lesson-plan-builder

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The expanding universe and the Big Bang

Name

Date

Score/ 8

  1. Question 1

    The Big Bang: which statement is true?

    • A. The Earth is the centre of the universe.
    • B. The Big Bang was an explosion at one point in an existing empty space.
    • C. Red-shift is evidence that the universe is expanding.
    • D. Red-shift means galaxies are moving towards us.

  2. Question 2

    More distant galaxies show greater red-shift. What does this suggest?

    • A. Galaxies are standing still
    • B. The universe is shrinking
    • C. Light slows down over time
    • D. The universe is expanding

  3. Question 3

    A spectral line normally at 656 nm is observed at 688.8 nm in light from a galaxy. By how many nanometres has it been red-shifted?

    Answernm

  4. Question 4

    What is the cosmic microwave background radiation (CMB)?

    • A. heat from the Sun
    • B. light from the Moon
    • C. leftover radiation from the early universe, seen in every direction
    • D. signals from mobile phones

  5. Question 5

    A spectral line normally at 656 nm is observed at 669.12 nm in light from a galaxy. By how many nanometres has it been red-shifted?

    Answernm

  6. Question 6

    A spectral line normally at 500 nm is observed at 505 nm in light from a galaxy. By how many nanometres has it been red-shifted?

    Answernm

  7. Question 7

    What is red-shift?

    • A. galaxies turning red because they are hot
    • B. light from distant galaxies is stretched to longer wavelengths
    • C. the Sun setting
    • D. light becoming bluer

  8. Question 8

    A spectral line normally at 500 nm is observed at 550 nm in light from a galaxy. By how many nanometres has it been red-shifted?

    Answernm

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Answer key: The expanding universe and the Big Bang

  1. 1. C. Red-shift is evidence that the universe is expanding.

  2. 2. D. The universe is expanding

  3. 3. 32.8 nm

  4. 4. C. leftover radiation from the early universe, seen in every direction

  5. 5. 13.12 nm

  6. 6. 5 nm

  7. 7. B. light from distant galaxies is stretched to longer wavelengths

  8. 8. 50 nm