👩 Teacher’s Guide

🎯 Objective

Students will be able to:

• Understand the basic ideas of half-life
• Use correct science vocabulary
• Explain real-world uses and safety issues

📝 Teaching Notes

• Key idea to emphasize: Time for half the radioactive nuclei to decay.
• Common misconception: All radiation is man-made (many sources are natural).
• Suggested teaching approach:
  • Use simple diagrams and analogies
  • Connect to medicine, energy, and everyday life
  • Keep explanations age-appropriate and clear

💬 Discussion Starter

Ask students:

• Why do atoms have different isotopes?
• How can radiation be both useful and dangerous?

🧒 Student Worksheet

Concept and Helping Material

Time for half the radioactive nuclei to decay.

Vocabulary and Definitions

• — Time for half the radioactive nuclei to decay.
• — One half.
• — One quarter.
• — 30 years.
• — No.

Hands-On Experiment or Activities

Activity 1: Coin half-life model
What You Need: 30 coins
What You Do: Toss coins, remove heads each round, record remaining.
Think and Talk: What changed? What stayed the same?

Activity 2: Radiation shielding demo (safe simulation)
What You Need: flashlight, paper, cardboard, thick book
What You Do: Shine light through materials to model penetration differences.
Think and Talk: What changed? What stayed the same?

Practice Questions (QA)

1. What is half-life?
2. After one half-life, what fraction remains?
3. After two half-lives, what fraction remains?
4. If half-life is 10 years, how long for 3 half-lives?
5. Does half-life depend on amount of substance?
6. What is one important idea about half-life?
7. What is one important idea about half-life?
8. What is one important idea about half-life?
9. What is one important idea about half-life?
10. What is one important idea about half-life?

Reflection

• Why is learning about half-life important?
• What is one way to reduce radiation risk?