Science lesson plan · 8th grade (Year 9 in England) · 30 minutes
Earth's 4.6-billion-year history on a timeline
Earth and rocks
CCSS NGSS.MS-ESS1-4England: KS3 Chemistry: Earth and atmosphereEngland: KS3 Biology: Evolution
Objective and success criteria
Students will: Earth's 4.6-billion-year history on a timeline.
- 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: Use rock layers to put events in order
Leads to: How Earth's atmosphere changed over time; Date rocks and fossils with radioactive decay
Materials: Rock samples, Hand lenses, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Use rock layers to put events in order). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Undisturbed rock layers, listed from the bottom up: B, E, C, A. Which layer is the youngest? (C / B / E / A) → APrompt: Sediment settles on top of what is already there.
- A crack filled with igneous rock (a dyke) cuts through layers A, B and C. What can you say about its age? (It is older than all three layers / It is younger than all three layers / Its age cannot be compared / It is the same age as layer B) → It is younger than all three layersPrompt: A layer must exist before something can cut through it.
- Undisturbed rock layers, listed from the bottom up: A, C, E. Which layer is the oldest? (E / C / A) → APrompt: Sediment settles on top of what is already there.
Hook · 3 min
- Pass round different rocks and ask how each one might have formed.
- Share the objective: Earth's 4.6-billion-year history on a timeline. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Imagine Earth's 4.6-billion-year history squeezed into one 24-hour day. How many minutes before midnight the first flowering plants appeared (130 million years ago)? Give 1 decimal place.
- Step 1: 130 ÷ 4600 = 0.02826
- Step 2: 0.02826 × 1440 = 40.7
- Step 3: So the answer is: 40.7 min
- Answer: 40.7 min
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Imagine Earth's 4.6-billion-year history squeezed into one 24-hour day. How many minutes before midnight the first dinosaurs appeared (230 million years ago)? Give 1 decimal place. → 72 minPrompt: Find what fraction of Earth's history this is.
- Which came next after this: Earth forms (about 4.6 billion years ago)? (first simple life in the oceans (about 3.8 billion years ago) / Cambrian explosion of animal life (about 540 million years ago) / first dinosaurs (about 230 million years ago) / oxygen starts building up in the air (about 2.4 billion years ago)) → first simple life in the oceans (about 3.8 billion years ago)Prompt: Use the approximate dates to compare.
You do: independent practice · 7 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 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Which came next after this: first dinosaurs (about 230 million years ago)? (Cambrian explosion of animal life (about 540 million years ago) / Earth forms (about 4.6 billion years ago) / first simple life in the oceans (about 3.8 billion years ago) / non-bird dinosaurs die out (66 million years ago)) → non-bird dinosaurs die out (66 million years ago)Prompt: Use the approximate dates to compare.
- Imagine Earth's 4.6-billion-year history squeezed into one 24-hour day. How many minutes before midnight the first land plants appeared (470 million years ago)? Give 1 decimal place. → 147.1 minPrompt: Find what fraction of Earth's history this is.
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: Use rock layers to put events in order.
- Use concrete materials: rock samples.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: How Earth's atmosphere changed over time; Date rocks and fossils with radioactive decay.
- 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-8.
Free lesson plan from eurekami.com/lesson-plan-builder